Anders Liljas - Academia.edu (original) (raw)

Papers by Anders Liljas

Acta crystallographica. Section D, Structural biology, 2021

The early part of the 20th century was a highly exciting scientific period in many respects, one ... more The early part of the 20th century was a highly exciting scientific period in many respects, one of these being that it gave birth to a new science, structural biology. This field has continued to have a great impact on biology in general since methods were developed to see the atomic arrangements of the molecules of life, nucleic acids, proteins, lipids and carbohydrates. A recent book describes these developments from the valuable and closeup perspective of Sir John Meurig Thomas. It is an excellent book for all interested in the history of science. The book deals with how it all began with the discovery in 1912 by Max von Laue, in Munich, that crystals diffracted X-rays. This provided not only the understanding that X-rays were electromagnetic radiation of short wavelength but also that crystals were well organized objects. This led father and son William Henry and William Lawrence Bragg, in Leeds and Cambridge, to realise that such experiments could lead to the structure of crystals. In the same year the son, William Laurence Bragg (WLB), had already determined the structure of some alkali halides and other simple compounds. It was obvious that the method could be further developed to determine the structures of more complex structures. The field took a great leap when John Desmond Bernal and Dorothy Crowfoot (later Hodgkin) took the first diffraction pictures of a protein crystal (pepsin). Max Perutz then began studies in Cambridge with the aim to determine the structure of haemoglobin. A strong supporter of this development was WLB, who by now was Professor of the Cavendish Laboratory. Since it seemed strange to perform biological work in a physics laboratory, he made a shed in the parking lot available to Perutz and his growing number of co-workers. The work in the shed, or the 'hut', was transferred to the newly created Medical Research Council Laboratory for Molecular Biology (LMB) at the end of the 1960s. Parallel to the work on developing methods to determine the structures of proteins and nucleic acids, Perutz, WLB, Francis Crick and John Kendrew (the latter two being Perutz's graduate students), tried to generate models of the structure of proteins. Early work was also done by Maurice L. Huggins. Crystal structures of amino acids and basic information from the X-ray diffraction patterns of proteins provided constraints. The Cambridge workers were beaten to discovering the correct structures by Pauling, Corey and Branson at Caltech, who had not only realised that the peptide group is planar but also that the helical structure did not need to have an integer number of residues in each turn. They proposed both the-helix and-structures. In addition to Francis Crick's contributions to the protein work, he and Jim Watson focused on the structure of DNA, the genetic material of all organisms. However, the book only gives limited insight into this exciting field as the focus of the book is on proteins. Thus, the breakthrough on the structures of myoglobin in 1959 and haemoglobin in 1965 by Kendrew, Perutz and their co-workers are well covered. Here the observations of-helices could be enjoyed in multiple examples. Parts of the physiological insights from the structural results are also discussed. The next step in the arena of proteins was the first structure of an enzyme, lysozyme, in 1965. This was owing to David Phillips and his co-workers working at the Davy-Faraday Research Laboratory at the Royal Institution in London directed by WLB. Here, not only was the first-structure observed but also the binding of substrates led to discussions of the catalytic mechanism. Yet another laboratory in the UK is highlighted. This is Dorothy Crowfoot Hodgkin's laboratory at Oxford University. She had earlier determined structures of smaller

IUCrJ, 2020

Carbonic anhydrase (CA) is a very well known enzyme that was discovered more than 80 years ago (M... more Carbonic anhydrase (CA) is a very well known enzyme that was discovered more than 80 years ago (Meldrum & Roughton, 1933). It is responsible for catalyzing the conversion of carbon dioxide to bicarbonate in all cells and the opposite conversion in the lungs. Several forms of the enzyme have been identified as well as numerous isoenzymes of the human form (Lomelino et al., 2018). The different forms are found in different species and isoenzymes are located in various human cell types. An exciting discovery is that isoenzymes IX and XII are associated with cancer cells and are probably important for cancer growth (Pastorekova et al., 2007, 2008). All carbonic anhydrases are metal enzymes, with zinc as the prime metal. In the first structure of carbonic anhydrase (CAII), a zinc ion was seen bound to three histidine residues at the core of the active site (Liljas et al., 1972). In studies of nitride reductase it was observed that the metal, in this case copper, was bound at two sites, type 1 and type 2. The type 2 copper is bound with the same configuration as in CA, by three histidines (Strange et al., 1995). Based on the similarity in substrate structure, Aamand et al. (2009) investigated whether CA could reduce nitrite. They found this to be the case but an explanation could not be envisioned. Andring et al. (2018) also made a thorough study but could not repeat the results of Aamand et al. (2009). Among the extensive crystallographic investigations of CA some have involved changing the metal. Hå kansson et al. (1994) observed that when the zinc ion was exchanged for copper, one additional copper site could be observed. This was in the floppy N-terminal region containing two His residues. In addition, they observed a presumed diatomic molecule bound to the copper at the classical active site. Similarly, Ferraroni et al. (2018) observed two copper atoms bound as well as the diatomic molecule at the active site. Neither of these studies made any connection to nitrite reductase. In the current issue of IUCrJ, Andring et al. (2020) have been able to unravel the mystery. Carbonic anhydrase (CAII) binds zinc as well as copper physiologically. The zinc-bound enzyme catalyzes the reversible conversion between carbon dioxide and bicarbonate. The same enzyme with two bound copper ions functions as a nitrite reductase. The classical active site for copper is site 2 where the reduction takes place. The diatomic 'molecule' seen in several studies is here interpreted as NO 2 À that has somehow been generated. At the other site (1) at the N-terminus copper binds in a manner that imitates binding to a porphyrin ring. The role of this site is to reduce the copper in the active site. The flexible His64 between the two sites, as well as a number of bound water molecules, are probably engaged in electron transport between the two sites (Fig. 1). This discovery, which has eluded the field for so long, is both remarkable and unusual. The long-standing assumption of a relatively simple role for the enzyme carbonic anhydrase has missed its second role as a more complex nitrite reductase. This discovery should lead to further experiments and research to better elucidate the role of this enzyme and decipher how these new insights could be applied in medical treatments.

IUCrJ, 2018

Carbonic anhydrase is among the most thoroughly investigated enzymes. It catalyzes the conversion... more Carbonic anhydrase is among the most thoroughly investigated enzymes. It catalyzes the conversion between carbon dioxide and bicarbonate CO 2 þ H 2 O Ð H þ þ HCO À 3 scientific commentaries IUCrJ (2018). 5, 4-5 Anders Liljas Carbonic anhydrase under pressure 5 Figure 1 A likely catalytic mechanism for human carbonic anhydrase II. In the first step (a) the zinc water (W Zn) releases a proton to His64 via W1 and W2. When carbon dioxide binds (b) it releases the two deep-water molecules. W1 disappears and is replaced by W I. His64 adopts the outward orientation to release the abstracted proton to bulk solvent. Then the W Zn makes a nucleophilic attack on the carbon of the carbon dioxide to form bicarbonate (c). Three water molecules rapidly replace the bicarbonate and His64 returns to its inward orientation (a). Several additional water molecules are identified and participate in the dynamic water structure of the active site.

Acta crystallographica. Section D, Structural biology, 2018

Structural Chemistry, 2016

Human activities have been marred for ages by conflicts of interest. This is no less true in the ... more Human activities have been marred for ages by conflicts of interest. This is no less true in the field of science. In the early years of the Nobel Prizes, little attention was focused on this aspect, but awareness steadily grew. In particular, this concerned Swedes nominated for Nobel Prizes, who were most likely themselves members of the Royal Swedish Academy of Sciences, but whose fellows at the Academy should treat them equally with respect to foreign nominees. In addition, conflicts of interest can arise when committee members have close contacts with nominated scientists, regardless of nationality.

Acta Physica Polonica A, 2002

P r oceedi ng s o f t h e Sy m p o siu m o n Syn chr otr on Cr y st all ogr ap hy, Kr y n ica, Po... more P r oceedi ng s o f t h e Sy m p o siu m o n Syn chr otr on Cr y st all ogr ap hy, Kr y n ica, Po l an d 200 1 D esi gn of a 5-Station Ma cro m olecu lar C r y stallogra p hy B eam lin e at M A X-L ab C.B. M ammen a , T. U r sby b , Y. Cere n ius b ;c , M. T hun nis sen c , J. A l s-N iel sen a , S. La rs en d and A. Li l ja s b a Ni els Bo h r I nsti t ute, â rste d L abo rato r y, Uni versi ty of Cop enhagen Uni versi tetspa rken 5, 2100 Co penha gen, Denm ark b M A X-l ab, Lund Uni versi ty , P.O. Bo x 118, 221 00 Lund, Sweden c Mo l ecul ar Bi ophysi cs, Center for Chem i stry and Chem ical Eng i neeri ng Lund Uni versi ty , P.O. Bo x 124, 221 00 Lund, Sweden d Centre for Crysta l l ogra phi c Studi es, D epartm ent of Chem i stry Uni versi ty of Cop enhagen Uni versi tetspa rken 5, 2100 Co penha gen, Denm ark A beam l ine for ma cromolec ular cr y stallo gra phy is un der construction at the Swedish synchrotron light source MA X-lab at Lund U niversity in a collab ora tiv e e˜ort b etw een Denmar k and Sw eden. Of the 7 mrad hori zontal w iggler fan emitted from the new superconducti ng multip ole wiggler , the central 2 mrad will be used and split in three parts. T he central 1 mrad w ill be used for a tunable station optimised for multi-wavelength anomalous di˜racti on exp eriments and on each side of the central fan there w ill b e tw o Ùxed wavelength stations using di˜erent energies of the same part of the beam. T hese in total Ùve stations can be used simultaneousl y and indep end ently for collecti ng di˜ractio n data.

Crystallography Reviews, 2014

Early on, crystallography was a domain of mineralogy and mathematics and dealt mostly with symmet... more Early on, crystallography was a domain of mineralogy and mathematics and dealt mostly with symmetry properties and imaginary crystal lattices. This changed when Wilhelm Conrad Röntgen discovered X-rays in 1895, and in 1912 Max von Laue and his associates discovered X-ray irradiated salt crystals would produce diffraction patterns that could reveal the internal atomic periodicity of the crystals. In the same year the father-and-son team, Henry and Lawrence Bragg successfully solved the first crystal structure of sodium chloride and the era of modern crystallography began. Protein crystallography (PX) started some 20 years later with the pioneering work of British crystallographers. In the past 50-60 years, the achievements of modern crystallography and particularly those in protein crystallography have been due to breakthroughs in theoretical and technical advancements such as phasing and direct methods; to more powerful X-ray sources such as synchrotron radiation (SR); to more sensitive and efficient X-ray detectors; to ever faster computers and to improvements in software. The exponential development of protein crystallography has been accelerated by the invention and applications of recombinant DNA technology that can yield nearly any protein of interest in large amounts and with relative ease. Novel methods, informatics platforms, and technologies for automation and high-throughput have allowed the development of large-scale, high efficiency macromolecular crystallography efforts in the field of structural genomics (SG). Very recently, the X-ray free-electron laser (XFEL) sources and its applications in protein crystallography have shown great potential for revolutionizing the whole field again in the near future.

Proceedings of the National Academy of Sciences, 1973

The binding of coenzyme and substrate are considered in relation to the known primary and tertiar... more The binding of coenzyme and substrate are considered in relation to the known primary and tertiary structure of lactate dehydrogenase (EC 1.1.1.27). The adenine binds in a hydrophobic crevice, and the two coenzyme phosphates are oriented by interactions with the protein. The positively charged guanidinium group of arginine 101 then folds over the negatively charged phosphates, collapsing the loop region over the active center and positioning the unreactive B side of the nicotinamide in a hydrophobic protein environment. Collapse of the loop also introduces various charged groups into the vicinity of the substrate binding site. The substrate is situated between histidine 195 and the C4 position on the nicotinamide ring, and is partially oriented by interactions between its carboxyl group and arginine 171. The spatial arrangements of these groups may provide the specificity for the L-isomer of lactate.

Proceedings of the National Academy of Sciences, 1973

About 80% of the aminoacid sequence of dogfish (Squalus acanthius) M4 lactate dehydrogenase (EC 1... more About 80% of the aminoacid sequence of dogfish (Squalus acanthius) M4 lactate dehydrogenase (EC 1.1.1.27) has been elucidated. Several sequence homologies with peptides from pig H4 and pig M4 lactate dehydrogenase are identified. Histidine 195 is homologous to the essential histidine residue in pig H4 lactate dehydrogenase. Similarities in the sequence around the "essential" cysteine residue of lactate dehydrogenase, glyceraldehyde-3phosphate dehydrogenase, and yeast and liver alcohol dehydrogenases are delineated.

Journal of Applied Crystallography, 1978

Neutron small-angle scattering with the contrast-variation method has established that for 50S an... more Neutron small-angle scattering with the contrast-variation method has established that for 50S and 70S ribosomal particles the RNA-protein distribution is such that the RNA component is located predominantly towards the interior and the protein towards the exterior of the particle. In contrast, the 30S subunit is much more homogeneous in its RNA-protein distribution. The shape of the 50S subunit has been determined at low resolution.

Journal of Applied Crystallography, 2003

The European Crystallographic Association (ECA) invites nominations for the fourth European Cryst... more The European Crystallographic Association (ECA) invites nominations for the fourth European Crystallography Prize to recognize a signi®cant achievement or discovery in crystallography in the past 5±10 years. Nominees should be af®liated or identi®ed with the European crystallographic community, as broadly de®ned in the charter of the ECA (see the ECA-news site, www.ecanews.org) The prize, including a monetary award and certi®cate of recognition, will be awarded at the opening ceremony of the 22nd European Crystallography Meeting

FEBS Letters, 1994

It has recently been shown that aliphatic sulphonamides are good inhibitors of carbonic anhydrase... more It has recently been shown that aliphatic sulphonamides are good inhibitors of carbonic anhydrase (CA) provided that the pK of the sulphonamide is low. We have determined the structure of the complex between CAII and CF3SO2NH2 by X-ray crystallographic methods. The nitrogen of the sulphonamide is bound to the zinc ion of the enzyme in the usual manner. The other parts of the inhibitor show a different mode of binding from aromatic sulphonamides since the trifluoromethyl group is bound at the hydrophobic part of the active site instead of pointing out from the active site. It should be possible to design new inhibitors specific for the different isoenzymes, starting from the present structure.

FEBS Letters, 1993

The three-dimensional structure of human carbonic anhydrase II complexed with azide and with brom... more The three-dimensional structure of human carbonic anhydrase II complexed with azide and with bromide was investigated crystallographically. Both of these non-protonated inhibitors replace the zinc and the 'deep' water, two catalytically important water molecules in the active site of the molecule. Both the azide and the bromide ions bind in a distorted tetrahedral manner 0.4 and 1.1 A from the zinc water position, respectively, but are in close contact (2.0 and 2.6 A, respectively) with the zinc ion.

Acta crystallographica. Section D, Structural biology, 2021

The early part of the 20th century was a highly exciting scientific period in many respects, one ... more The early part of the 20th century was a highly exciting scientific period in many respects, one of these being that it gave birth to a new science, structural biology. This field has continued to have a great impact on biology in general since methods were developed to see the atomic arrangements of the molecules of life, nucleic acids, proteins, lipids and carbohydrates. A recent book describes these developments from the valuable and closeup perspective of Sir John Meurig Thomas. It is an excellent book for all interested in the history of science. The book deals with how it all began with the discovery in 1912 by Max von Laue, in Munich, that crystals diffracted X-rays. This provided not only the understanding that X-rays were electromagnetic radiation of short wavelength but also that crystals were well organized objects. This led father and son William Henry and William Lawrence Bragg, in Leeds and Cambridge, to realise that such experiments could lead to the structure of crystals. In the same year the son, William Laurence Bragg (WLB), had already determined the structure of some alkali halides and other simple compounds. It was obvious that the method could be further developed to determine the structures of more complex structures. The field took a great leap when John Desmond Bernal and Dorothy Crowfoot (later Hodgkin) took the first diffraction pictures of a protein crystal (pepsin). Max Perutz then began studies in Cambridge with the aim to determine the structure of haemoglobin. A strong supporter of this development was WLB, who by now was Professor of the Cavendish Laboratory. Since it seemed strange to perform biological work in a physics laboratory, he made a shed in the parking lot available to Perutz and his growing number of co-workers. The work in the shed, or the 'hut', was transferred to the newly created Medical Research Council Laboratory for Molecular Biology (LMB) at the end of the 1960s. Parallel to the work on developing methods to determine the structures of proteins and nucleic acids, Perutz, WLB, Francis Crick and John Kendrew (the latter two being Perutz's graduate students), tried to generate models of the structure of proteins. Early work was also done by Maurice L. Huggins. Crystal structures of amino acids and basic information from the X-ray diffraction patterns of proteins provided constraints. The Cambridge workers were beaten to discovering the correct structures by Pauling, Corey and Branson at Caltech, who had not only realised that the peptide group is planar but also that the helical structure did not need to have an integer number of residues in each turn. They proposed both the-helix and-structures. In addition to Francis Crick's contributions to the protein work, he and Jim Watson focused on the structure of DNA, the genetic material of all organisms. However, the book only gives limited insight into this exciting field as the focus of the book is on proteins. Thus, the breakthrough on the structures of myoglobin in 1959 and haemoglobin in 1965 by Kendrew, Perutz and their co-workers are well covered. Here the observations of-helices could be enjoyed in multiple examples. Parts of the physiological insights from the structural results are also discussed. The next step in the arena of proteins was the first structure of an enzyme, lysozyme, in 1965. This was owing to David Phillips and his co-workers working at the Davy-Faraday Research Laboratory at the Royal Institution in London directed by WLB. Here, not only was the first-structure observed but also the binding of substrates led to discussions of the catalytic mechanism. Yet another laboratory in the UK is highlighted. This is Dorothy Crowfoot Hodgkin's laboratory at Oxford University. She had earlier determined structures of smaller

IUCrJ, 2020

Carbonic anhydrase (CA) is a very well known enzyme that was discovered more than 80 years ago (M... more Carbonic anhydrase (CA) is a very well known enzyme that was discovered more than 80 years ago (Meldrum & Roughton, 1933). It is responsible for catalyzing the conversion of carbon dioxide to bicarbonate in all cells and the opposite conversion in the lungs. Several forms of the enzyme have been identified as well as numerous isoenzymes of the human form (Lomelino et al., 2018). The different forms are found in different species and isoenzymes are located in various human cell types. An exciting discovery is that isoenzymes IX and XII are associated with cancer cells and are probably important for cancer growth (Pastorekova et al., 2007, 2008). All carbonic anhydrases are metal enzymes, with zinc as the prime metal. In the first structure of carbonic anhydrase (CAII), a zinc ion was seen bound to three histidine residues at the core of the active site (Liljas et al., 1972). In studies of nitride reductase it was observed that the metal, in this case copper, was bound at two sites, type 1 and type 2. The type 2 copper is bound with the same configuration as in CA, by three histidines (Strange et al., 1995). Based on the similarity in substrate structure, Aamand et al. (2009) investigated whether CA could reduce nitrite. They found this to be the case but an explanation could not be envisioned. Andring et al. (2018) also made a thorough study but could not repeat the results of Aamand et al. (2009). Among the extensive crystallographic investigations of CA some have involved changing the metal. Hå kansson et al. (1994) observed that when the zinc ion was exchanged for copper, one additional copper site could be observed. This was in the floppy N-terminal region containing two His residues. In addition, they observed a presumed diatomic molecule bound to the copper at the classical active site. Similarly, Ferraroni et al. (2018) observed two copper atoms bound as well as the diatomic molecule at the active site. Neither of these studies made any connection to nitrite reductase. In the current issue of IUCrJ, Andring et al. (2020) have been able to unravel the mystery. Carbonic anhydrase (CAII) binds zinc as well as copper physiologically. The zinc-bound enzyme catalyzes the reversible conversion between carbon dioxide and bicarbonate. The same enzyme with two bound copper ions functions as a nitrite reductase. The classical active site for copper is site 2 where the reduction takes place. The diatomic 'molecule' seen in several studies is here interpreted as NO 2 À that has somehow been generated. At the other site (1) at the N-terminus copper binds in a manner that imitates binding to a porphyrin ring. The role of this site is to reduce the copper in the active site. The flexible His64 between the two sites, as well as a number of bound water molecules, are probably engaged in electron transport between the two sites (Fig. 1). This discovery, which has eluded the field for so long, is both remarkable and unusual. The long-standing assumption of a relatively simple role for the enzyme carbonic anhydrase has missed its second role as a more complex nitrite reductase. This discovery should lead to further experiments and research to better elucidate the role of this enzyme and decipher how these new insights could be applied in medical treatments.

IUCrJ, 2018

Carbonic anhydrase is among the most thoroughly investigated enzymes. It catalyzes the conversion... more Carbonic anhydrase is among the most thoroughly investigated enzymes. It catalyzes the conversion between carbon dioxide and bicarbonate CO 2 þ H 2 O Ð H þ þ HCO À 3 scientific commentaries IUCrJ (2018). 5, 4-5 Anders Liljas Carbonic anhydrase under pressure 5 Figure 1 A likely catalytic mechanism for human carbonic anhydrase II. In the first step (a) the zinc water (W Zn) releases a proton to His64 via W1 and W2. When carbon dioxide binds (b) it releases the two deep-water molecules. W1 disappears and is replaced by W I. His64 adopts the outward orientation to release the abstracted proton to bulk solvent. Then the W Zn makes a nucleophilic attack on the carbon of the carbon dioxide to form bicarbonate (c). Three water molecules rapidly replace the bicarbonate and His64 returns to its inward orientation (a). Several additional water molecules are identified and participate in the dynamic water structure of the active site.

Acta crystallographica. Section D, Structural biology, 2018

Structural Chemistry, 2016

Human activities have been marred for ages by conflicts of interest. This is no less true in the ... more Human activities have been marred for ages by conflicts of interest. This is no less true in the field of science. In the early years of the Nobel Prizes, little attention was focused on this aspect, but awareness steadily grew. In particular, this concerned Swedes nominated for Nobel Prizes, who were most likely themselves members of the Royal Swedish Academy of Sciences, but whose fellows at the Academy should treat them equally with respect to foreign nominees. In addition, conflicts of interest can arise when committee members have close contacts with nominated scientists, regardless of nationality.

Acta Physica Polonica A, 2002

P r oceedi ng s o f t h e Sy m p o siu m o n Syn chr otr on Cr y st all ogr ap hy, Kr y n ica, Po... more P r oceedi ng s o f t h e Sy m p o siu m o n Syn chr otr on Cr y st all ogr ap hy, Kr y n ica, Po l an d 200 1 D esi gn of a 5-Station Ma cro m olecu lar C r y stallogra p hy B eam lin e at M A X-L ab C.B. M ammen a , T. U r sby b , Y. Cere n ius b ;c , M. T hun nis sen c , J. A l s-N iel sen a , S. La rs en d and A. Li l ja s b a Ni els Bo h r I nsti t ute, â rste d L abo rato r y, Uni versi ty of Cop enhagen Uni versi tetspa rken 5, 2100 Co penha gen, Denm ark b M A X-l ab, Lund Uni versi ty , P.O. Bo x 118, 221 00 Lund, Sweden c Mo l ecul ar Bi ophysi cs, Center for Chem i stry and Chem ical Eng i neeri ng Lund Uni versi ty , P.O. Bo x 124, 221 00 Lund, Sweden d Centre for Crysta l l ogra phi c Studi es, D epartm ent of Chem i stry Uni versi ty of Cop enhagen Uni versi tetspa rken 5, 2100 Co penha gen, Denm ark A beam l ine for ma cromolec ular cr y stallo gra phy is un der construction at the Swedish synchrotron light source MA X-lab at Lund U niversity in a collab ora tiv e e˜ort b etw een Denmar k and Sw eden. Of the 7 mrad hori zontal w iggler fan emitted from the new superconducti ng multip ole wiggler , the central 2 mrad will be used and split in three parts. T he central 1 mrad w ill be used for a tunable station optimised for multi-wavelength anomalous di˜racti on exp eriments and on each side of the central fan there w ill b e tw o Ùxed wavelength stations using di˜erent energies of the same part of the beam. T hese in total Ùve stations can be used simultaneousl y and indep end ently for collecti ng di˜ractio n data.

Crystallography Reviews, 2014

Early on, crystallography was a domain of mineralogy and mathematics and dealt mostly with symmet... more Early on, crystallography was a domain of mineralogy and mathematics and dealt mostly with symmetry properties and imaginary crystal lattices. This changed when Wilhelm Conrad Röntgen discovered X-rays in 1895, and in 1912 Max von Laue and his associates discovered X-ray irradiated salt crystals would produce diffraction patterns that could reveal the internal atomic periodicity of the crystals. In the same year the father-and-son team, Henry and Lawrence Bragg successfully solved the first crystal structure of sodium chloride and the era of modern crystallography began. Protein crystallography (PX) started some 20 years later with the pioneering work of British crystallographers. In the past 50-60 years, the achievements of modern crystallography and particularly those in protein crystallography have been due to breakthroughs in theoretical and technical advancements such as phasing and direct methods; to more powerful X-ray sources such as synchrotron radiation (SR); to more sensitive and efficient X-ray detectors; to ever faster computers and to improvements in software. The exponential development of protein crystallography has been accelerated by the invention and applications of recombinant DNA technology that can yield nearly any protein of interest in large amounts and with relative ease. Novel methods, informatics platforms, and technologies for automation and high-throughput have allowed the development of large-scale, high efficiency macromolecular crystallography efforts in the field of structural genomics (SG). Very recently, the X-ray free-electron laser (XFEL) sources and its applications in protein crystallography have shown great potential for revolutionizing the whole field again in the near future.

Proceedings of the National Academy of Sciences, 1973

The binding of coenzyme and substrate are considered in relation to the known primary and tertiar... more The binding of coenzyme and substrate are considered in relation to the known primary and tertiary structure of lactate dehydrogenase (EC 1.1.1.27). The adenine binds in a hydrophobic crevice, and the two coenzyme phosphates are oriented by interactions with the protein. The positively charged guanidinium group of arginine 101 then folds over the negatively charged phosphates, collapsing the loop region over the active center and positioning the unreactive B side of the nicotinamide in a hydrophobic protein environment. Collapse of the loop also introduces various charged groups into the vicinity of the substrate binding site. The substrate is situated between histidine 195 and the C4 position on the nicotinamide ring, and is partially oriented by interactions between its carboxyl group and arginine 171. The spatial arrangements of these groups may provide the specificity for the L-isomer of lactate.

Proceedings of the National Academy of Sciences, 1973

About 80% of the aminoacid sequence of dogfish (Squalus acanthius) M4 lactate dehydrogenase (EC 1... more About 80% of the aminoacid sequence of dogfish (Squalus acanthius) M4 lactate dehydrogenase (EC 1.1.1.27) has been elucidated. Several sequence homologies with peptides from pig H4 and pig M4 lactate dehydrogenase are identified. Histidine 195 is homologous to the essential histidine residue in pig H4 lactate dehydrogenase. Similarities in the sequence around the "essential" cysteine residue of lactate dehydrogenase, glyceraldehyde-3phosphate dehydrogenase, and yeast and liver alcohol dehydrogenases are delineated.

Journal of Applied Crystallography, 1978

Neutron small-angle scattering with the contrast-variation method has established that for 50S an... more Neutron small-angle scattering with the contrast-variation method has established that for 50S and 70S ribosomal particles the RNA-protein distribution is such that the RNA component is located predominantly towards the interior and the protein towards the exterior of the particle. In contrast, the 30S subunit is much more homogeneous in its RNA-protein distribution. The shape of the 50S subunit has been determined at low resolution.

Journal of Applied Crystallography, 2003

The European Crystallographic Association (ECA) invites nominations for the fourth European Cryst... more The European Crystallographic Association (ECA) invites nominations for the fourth European Crystallography Prize to recognize a signi®cant achievement or discovery in crystallography in the past 5±10 years. Nominees should be af®liated or identi®ed with the European crystallographic community, as broadly de®ned in the charter of the ECA (see the ECA-news site, www.ecanews.org) The prize, including a monetary award and certi®cate of recognition, will be awarded at the opening ceremony of the 22nd European Crystallography Meeting

FEBS Letters, 1994

It has recently been shown that aliphatic sulphonamides are good inhibitors of carbonic anhydrase... more It has recently been shown that aliphatic sulphonamides are good inhibitors of carbonic anhydrase (CA) provided that the pK of the sulphonamide is low. We have determined the structure of the complex between CAII and CF3SO2NH2 by X-ray crystallographic methods. The nitrogen of the sulphonamide is bound to the zinc ion of the enzyme in the usual manner. The other parts of the inhibitor show a different mode of binding from aromatic sulphonamides since the trifluoromethyl group is bound at the hydrophobic part of the active site instead of pointing out from the active site. It should be possible to design new inhibitors specific for the different isoenzymes, starting from the present structure.

FEBS Letters, 1993

The three-dimensional structure of human carbonic anhydrase II complexed with azide and with brom... more The three-dimensional structure of human carbonic anhydrase II complexed with azide and with bromide was investigated crystallographically. Both of these non-protonated inhibitors replace the zinc and the 'deep' water, two catalytically important water molecules in the active site of the molecule. Both the azide and the bromide ions bind in a distorted tetrahedral manner 0.4 and 1.1 A from the zinc water position, respectively, but are in close contact (2.0 and 2.6 A, respectively) with the zinc ion.