Rita Mathews | SASTRA University (original) (raw)
Papers by Rita Mathews
Journal of Biophysics and Structural Biology, Sep 30, 2011
Ribonucleotide reductase (RR) is a ubiquitous cytosolic enzyme required for DNA synthesis and rep... more Ribonucleotide reductase (RR) is a ubiquitous cytosolic enzyme required for DNA synthesis and repair in all living cells. Therefore, the crucial role of this enzyme in cell division makes it a potential target for designing drugs that inhibit cell growth for cancer therapy. An increased interest in RR as a target for cancer therapy has been documented since the discovery that human RR is regulated by p53 enzyme and that a mutation in p53 leads to several forms of cancer. Cell proliferation stops if normal RR is inhibited. A new strategy to kill the cancer cells would be using specific inhibitors that inhibit the action of RR enzyme. The inhibitor must be a radical scavenger which destroys the tyrosyl radical or an iron metal scavenger (which affects iron center). In this view, modeling studies on human RR-R2 were done to understand its interaction with radical scavengers, flavin (FLA) and phenosafranine (PHE) through docking since they have good reductive property. Radical scavengers are active against RR enzymes at anaerobic condition and their radical scavenging mechanism has been proposed. In aerobic condition RR enzyme will reproduce the radicals and then the radical scavengers fail to act as drug. So, the metal scavengers may be better than the radical scavengers to curtail the action of RR enzyme.
Bruker SMART APEX CCD areadetector diffractometer Absorption correction: refined from F (XABS; Pa... more Bruker SMART APEX CCD areadetector diffractometer Absorption correction: refined from F (XABS; Parkin et al. 1995) Tmin = 0.703, Tmax = 0.999
Molecular Crystals and Liquid Crystals, 2010
... E-mail: sampath@ konkuk.ac.kr or MN Ponnuswamy, Department of Crystallography and Biophysics,... more ... E-mail: sampath@ konkuk.ac.kr or MN Ponnuswamy, Department of Crystallography and Biophysics, Univer-sity of Madras, Guindy Campus, Chennai, India. ... Chem., 22, 1367. [7] Nagarajan, K., Talwalker, PK, Kulkarni, CL, Venkateswaralu, A., Prabhu, SS, & Nayak, GV (1984). ...
Journal of Chemical Crystallography, 2010
Thiosemicarbazones (TSCs) are very versatile tridentate ligands having the ability to bind transi... more Thiosemicarbazones (TSCs) are very versatile tridentate ligands having the ability to bind transition metal ions by bonding through sulfur and hydrazinic terminal nitrogen atoms. TSC also inhibits the enzyme ribonucliotide diphosphate reductase (RDR) which is involved in the synthesis of DNA precursors in the mammalian cells. One of the important heterocyclic thiosemicarbazones, the title compound (MBCPT) has been synthesized based on the Mannich reaction and it was characterized by X-ray diffraction methods. The crystallographic data of MBCPT are: C 19 H 20 Cl 2 N 4 S; M.W = 407.35, Monoclinic, space group, P2 1 /n, with cell parameters a = 12.053(8) Å , b = 11.431(10) Å , c = 14.695(7) Å , b = 95.82(4)8; V = 2014(2) Å 3 , Z = 4, D cal = 1.343 Mg/m 3 , k (Cu K a) = 1.54184 Å. The ring piperine adopts chair conformation. The phenyl rings are oriented equatorially at 2 and 6th positions of the piperidine ring. Molecular packing can be viewed as a dimer held together by two N-H_S intermolecular hydrogen bonds. Molecules are tightly bound in the unit cell by C-H_N, N-H_S and N-H_N types inter and intra molecular hydrogen bonds.
Journal of Chemical Crystallography, 2010
Thiosemicarbazones (TSCs) are very versatile tridentate ligands having the ability to bind transi... more Thiosemicarbazones (TSCs) are very versatile tridentate ligands having the ability to bind transition metal ions by bonding through sulfur and hydrazinic terminal nitrogen atoms. TSC also inhibits ribonucleotide diphosphate reductase (RDR), the enzyme involved in the synthesis of DNA precursors in the mammalian cells. One of the important phenyl thiosemicarbazones, the title compound (p-CBT) has been synthesized and it was characterized by X-ray diffraction methods. The crystallographic data of p-CBT are: C 8 H 8 ClN 3 S; M.W. = 213.68, Triclinic, space group, Pī, with cell parameters a = 7.934(2) Å , b = 11.242(3) Å , c = 11.615(2) Å , a = 74.775(3), b = 75.389(2), c = 83.448(2); V = 966.0(4) Å 3 , Z = 4, Dcal = 1.469 Mg/m 3 , k (Cu K a) = 1.54184 Å. Molecular packing can be viewed as a dimer held together by two N-H…S type intermolecular hydrogen bonds. In addition, C-H…Cl and N-H…N types of inter and intra molecular hydrogen bonds also help the molecules in crystal packing.
Journal of Chemical Crystallography, 2010
Pyridocarbazole possesses many biological activities such as antimicrobial and antitumor properti... more Pyridocarbazole possesses many biological activities such as antimicrobial and antitumor properties. It also serves as a selective inhibitor for cyclic GMP phosphodiesterase (cGMP-PDE) enzyme. Since it is very similar to ellipticine and olivacine, its derivatives are endowed with DNA intercalating properties. One of the pyridocarbazoles, MCDDC, has been synthesized and its stereochemistry has been proven by X-ray crystallographic study. The crystal belongs to the monoclinic space group, P2 1 /a, with cell parameters a = 11.771(3) Å , b = 14.557(3) Å , c = 11.869(1) Å and b = 101.80(2)°. According to the X-ray structure, the entire MCDDC molecule adopts a planar conformation except for the dichlorophenyl ring, which is almost orthogonal to the pyridine ring. Molecules are tightly bound by the N-HÁÁÁN type hydrogen bonds and weak C-HÁÁÁp interactions also help in packing stabilization.
Journal of Chemical Crystallography, 2011
Two crystal structures of acridinediones namely, TMHAD and MPHAD were studied by X-ray crystallog... more Two crystal structures of acridinediones namely, TMHAD and MPHAD were studied by X-ray crystallographic method in view of their occurrence in numerous commercial products including pharmaceuticals, fragrances and dyes. Crystal data of TMHAD are: C 17 H 23 NO 2 , orthorhombic, Fdd2, with cell parameters a = 40.417(6) Å ,
Acta Crystallographica Section E Structure Reports Online, 2012
![Research paper thumbnail of (Z)-2-[(4-Methylphenyl)sulfonyl]-1,2-diphenyletheneselenol](https://attachments.academia-assets.com/95227211/thumbnails/1.jpg)
](Acta Crystallographica Section E Structure Reports Online, 2012
![Research paper thumbnail of 1′-Methyl-4′-phenyl-2′′-sulfanylidenedispiro[indoline-3,2′-pyrrolidine-3′,5′′-1,3-thiazolidine]-2,4′′-dione](https://attachments.academia-assets.com/95227208/thumbnails/1.jpg)
](Acta Crystallographica Section E Structure Reports Online, 2012
The title compound, C 20 H 17 N 3 O 2 S 2 , crystallizes with two molecules in the asymmetric uni... more The title compound, C 20 H 17 N 3 O 2 S 2 , crystallizes with two molecules in the asymmetric unit. The pyrrolodine rings have envelope conformations in both molecules, the N atoms deviating by 0.574 (3) and 0.612 (2) Å from the mean planes through the other ring atoms. The 1 0-methyl and 4 0-phenyl groups on the pyrrolidine rings are substituted in equatorial positions. In the crystal, molecules are linked into a threedimensional network by N-HÁ Á ÁO, N-HÁ Á ÁN and C-HÁ Á ÁO and N-HÁ Á Á hydrogen bonds.
![Research paper thumbnail of 4-({(E)-[2-(But-3-en-1-yl)-1-(prop-2-en-1-yl)-4-sulfanyl-1H-imidazol-5-yl]methylidene}amino)-3-phenyl-1H-1,2,4-triazole-5(4H)-thione](https://attachments.academia-assets.com/95227206/thumbnails/1.jpg)
](Acta Crystallographica Section E Structure Reports Online, 2011
Acta Crystallographica Section E Structure Reports Online, 2011
Acta Crystallographica Section E Structure Reports Online, 2011
Ethyl 3-methyl-2,6-diphenylpiperidine-1-carboxylate Sampath Natarajan and Rita Mathews S1. Commen... more Ethyl 3-methyl-2,6-diphenylpiperidine-1-carboxylate Sampath Natarajan and Rita Mathews S1. Comment Piperidines and its N-substituted derivatives show significant pharmacological properties (Parthiban et al., 2009; Aridoss et al., 2007). Substitution by electron withdrawing groups (CHO, COCH 2 CH 3 , COPh, NO, etc.) at N-th position of piperidine ring causes major changes in the ring conformation (Ravindran et al., 1991; Krishna Kumar & Krishna Pillay, 1996). In the title compound (Fig. 1), the ethylacetate group substituting the piperidine ring shows extended conformation and the hetero π electron delocalization through the atoms N1, C20, O1 and O2 causes twisted boat conformation for the piperidine core, with puckering amplitude, Q T = 0.718 (1) Å and phase angle = 89.5 (2)° (Nardelli, 1995; Cremer & Pople, 1975). The phenyl rings at C2 and C6 atoms are oriented in the axial and equatorial positions, respectively, and the dihedral angle between them is 49.8 (1)°. Similarly, the methyl group at C5 is also oriented in equatorial position. All these substitutions are confirmed by the respective torsion angles. In addition, the substitution of ethylacetate group on N1 atom showed extended conformation with respect to the piperidine ring, which is also confirmed by the torsion angles. supporting information sup-6
![Research paper thumbnail of 3-Nitroso-2,4,6,8-tetraphenyl-3,7-diazabicyclo[3.3.1]nonan-9-one](https://attachments.academia-assets.com/95227200/thumbnails/1.jpg)
](Acta Crystallographica Section E Structure Reports Online, 2011
Journal of Molecular Graphics and Modelling, 2020
Myelin Oligodendrocyte glycoprotein (MOG) is found to play an important role in providing structu... more Myelin Oligodendrocyte glycoprotein (MOG) is found to play an important role in providing structural integrity to myelin sheath at the same time it acts as an auto-antigen which might lead to Multiple Sclerosis (MS). What causes this specific property of being an auto-antigen is still not known. Here we present molecular dynamics simulation studies of unfolding and folding of the protein MOG in both the absence and presence of N-glycan in order to understand the role of glycosylation in the stability and flexibility of the protein. The main results from these studies show that the glycosylation increases the stability of the protein MOG and inhibits the complete unfolding of MOG in the SMD. From the folding studies using TMD, it was observed that the glycan helps the protein to attain the near-native folded conformation. However, it was also observed from the direct TMD studies that the pathway of protein folding was enhanced by the trace-back of intermediate states in the presence of glycan.
Journal of Biophysics and Structural Biology, Sep 30, 2011
Ribonucleotide reductase (RR) is a ubiquitous cytosolic enzyme required for DNA synthesis and rep... more Ribonucleotide reductase (RR) is a ubiquitous cytosolic enzyme required for DNA synthesis and repair in all living cells. Therefore, the crucial role of this enzyme in cell division makes it a potential target for designing drugs that inhibit cell growth for cancer therapy. An increased interest in RR as a target for cancer therapy has been documented since the discovery that human RR is regulated by p53 enzyme and that a mutation in p53 leads to several forms of cancer. Cell proliferation stops if normal RR is inhibited. A new strategy to kill the cancer cells would be using specific inhibitors that inhibit the action of RR enzyme. The inhibitor must be a radical scavenger which destroys the tyrosyl radical or an iron metal scavenger (which affects iron center). In this view, modeling studies on human RR-R2 were done to understand its interaction with radical scavengers, flavin (FLA) and phenosafranine (PHE) through docking since they have good reductive property. Radical scavengers are active against RR enzymes at anaerobic condition and their radical scavenging mechanism has been proposed. In aerobic condition RR enzyme will reproduce the radicals and then the radical scavengers fail to act as drug. So, the metal scavengers may be better than the radical scavengers to curtail the action of RR enzyme.
Bruker SMART APEX CCD areadetector diffractometer Absorption correction: refined from F (XABS; Pa... more Bruker SMART APEX CCD areadetector diffractometer Absorption correction: refined from F (XABS; Parkin et al. 1995) Tmin = 0.703, Tmax = 0.999
Molecular Crystals and Liquid Crystals, 2010
... E-mail: sampath@ konkuk.ac.kr or MN Ponnuswamy, Department of Crystallography and Biophysics,... more ... E-mail: sampath@ konkuk.ac.kr or MN Ponnuswamy, Department of Crystallography and Biophysics, Univer-sity of Madras, Guindy Campus, Chennai, India. ... Chem., 22, 1367. [7] Nagarajan, K., Talwalker, PK, Kulkarni, CL, Venkateswaralu, A., Prabhu, SS, & Nayak, GV (1984). ...
Journal of Chemical Crystallography, 2010
Thiosemicarbazones (TSCs) are very versatile tridentate ligands having the ability to bind transi... more Thiosemicarbazones (TSCs) are very versatile tridentate ligands having the ability to bind transition metal ions by bonding through sulfur and hydrazinic terminal nitrogen atoms. TSC also inhibits the enzyme ribonucliotide diphosphate reductase (RDR) which is involved in the synthesis of DNA precursors in the mammalian cells. One of the important heterocyclic thiosemicarbazones, the title compound (MBCPT) has been synthesized based on the Mannich reaction and it was characterized by X-ray diffraction methods. The crystallographic data of MBCPT are: C 19 H 20 Cl 2 N 4 S; M.W = 407.35, Monoclinic, space group, P2 1 /n, with cell parameters a = 12.053(8) Å , b = 11.431(10) Å , c = 14.695(7) Å , b = 95.82(4)8; V = 2014(2) Å 3 , Z = 4, D cal = 1.343 Mg/m 3 , k (Cu K a) = 1.54184 Å. The ring piperine adopts chair conformation. The phenyl rings are oriented equatorially at 2 and 6th positions of the piperidine ring. Molecular packing can be viewed as a dimer held together by two N-H_S intermolecular hydrogen bonds. Molecules are tightly bound in the unit cell by C-H_N, N-H_S and N-H_N types inter and intra molecular hydrogen bonds.
Journal of Chemical Crystallography, 2010
Thiosemicarbazones (TSCs) are very versatile tridentate ligands having the ability to bind transi... more Thiosemicarbazones (TSCs) are very versatile tridentate ligands having the ability to bind transition metal ions by bonding through sulfur and hydrazinic terminal nitrogen atoms. TSC also inhibits ribonucleotide diphosphate reductase (RDR), the enzyme involved in the synthesis of DNA precursors in the mammalian cells. One of the important phenyl thiosemicarbazones, the title compound (p-CBT) has been synthesized and it was characterized by X-ray diffraction methods. The crystallographic data of p-CBT are: C 8 H 8 ClN 3 S; M.W. = 213.68, Triclinic, space group, Pī, with cell parameters a = 7.934(2) Å , b = 11.242(3) Å , c = 11.615(2) Å , a = 74.775(3), b = 75.389(2), c = 83.448(2); V = 966.0(4) Å 3 , Z = 4, Dcal = 1.469 Mg/m 3 , k (Cu K a) = 1.54184 Å. Molecular packing can be viewed as a dimer held together by two N-H…S type intermolecular hydrogen bonds. In addition, C-H…Cl and N-H…N types of inter and intra molecular hydrogen bonds also help the molecules in crystal packing.
Journal of Chemical Crystallography, 2010
Pyridocarbazole possesses many biological activities such as antimicrobial and antitumor properti... more Pyridocarbazole possesses many biological activities such as antimicrobial and antitumor properties. It also serves as a selective inhibitor for cyclic GMP phosphodiesterase (cGMP-PDE) enzyme. Since it is very similar to ellipticine and olivacine, its derivatives are endowed with DNA intercalating properties. One of the pyridocarbazoles, MCDDC, has been synthesized and its stereochemistry has been proven by X-ray crystallographic study. The crystal belongs to the monoclinic space group, P2 1 /a, with cell parameters a = 11.771(3) Å , b = 14.557(3) Å , c = 11.869(1) Å and b = 101.80(2)°. According to the X-ray structure, the entire MCDDC molecule adopts a planar conformation except for the dichlorophenyl ring, which is almost orthogonal to the pyridine ring. Molecules are tightly bound by the N-HÁÁÁN type hydrogen bonds and weak C-HÁÁÁp interactions also help in packing stabilization.
Journal of Chemical Crystallography, 2011
Two crystal structures of acridinediones namely, TMHAD and MPHAD were studied by X-ray crystallog... more Two crystal structures of acridinediones namely, TMHAD and MPHAD were studied by X-ray crystallographic method in view of their occurrence in numerous commercial products including pharmaceuticals, fragrances and dyes. Crystal data of TMHAD are: C 17 H 23 NO 2 , orthorhombic, Fdd2, with cell parameters a = 40.417(6) Å ,
Acta Crystallographica Section E Structure Reports Online, 2012
Acta Crystallographica Section E Structure Reports Online, 2012
Acta Crystallographica Section E Structure Reports Online, 2012
The title compound, C 20 H 17 N 3 O 2 S 2 , crystallizes with two molecules in the asymmetric uni... more The title compound, C 20 H 17 N 3 O 2 S 2 , crystallizes with two molecules in the asymmetric unit. The pyrrolodine rings have envelope conformations in both molecules, the N atoms deviating by 0.574 (3) and 0.612 (2) Å from the mean planes through the other ring atoms. The 1 0-methyl and 4 0-phenyl groups on the pyrrolidine rings are substituted in equatorial positions. In the crystal, molecules are linked into a threedimensional network by N-HÁ Á ÁO, N-HÁ Á ÁN and C-HÁ Á ÁO and N-HÁ Á Á hydrogen bonds.
Acta Crystallographica Section E Structure Reports Online, 2011
Acta Crystallographica Section E Structure Reports Online, 2011
Acta Crystallographica Section E Structure Reports Online, 2011
Ethyl 3-methyl-2,6-diphenylpiperidine-1-carboxylate Sampath Natarajan and Rita Mathews S1. Commen... more Ethyl 3-methyl-2,6-diphenylpiperidine-1-carboxylate Sampath Natarajan and Rita Mathews S1. Comment Piperidines and its N-substituted derivatives show significant pharmacological properties (Parthiban et al., 2009; Aridoss et al., 2007). Substitution by electron withdrawing groups (CHO, COCH 2 CH 3 , COPh, NO, etc.) at N-th position of piperidine ring causes major changes in the ring conformation (Ravindran et al., 1991; Krishna Kumar & Krishna Pillay, 1996). In the title compound (Fig. 1), the ethylacetate group substituting the piperidine ring shows extended conformation and the hetero π electron delocalization through the atoms N1, C20, O1 and O2 causes twisted boat conformation for the piperidine core, with puckering amplitude, Q T = 0.718 (1) Å and phase angle = 89.5 (2)° (Nardelli, 1995; Cremer & Pople, 1975). The phenyl rings at C2 and C6 atoms are oriented in the axial and equatorial positions, respectively, and the dihedral angle between them is 49.8 (1)°. Similarly, the methyl group at C5 is also oriented in equatorial position. All these substitutions are confirmed by the respective torsion angles. In addition, the substitution of ethylacetate group on N1 atom showed extended conformation with respect to the piperidine ring, which is also confirmed by the torsion angles. supporting information sup-6
Acta Crystallographica Section E Structure Reports Online, 2011
Journal of Molecular Graphics and Modelling, 2020
Myelin Oligodendrocyte glycoprotein (MOG) is found to play an important role in providing structu... more Myelin Oligodendrocyte glycoprotein (MOG) is found to play an important role in providing structural integrity to myelin sheath at the same time it acts as an auto-antigen which might lead to Multiple Sclerosis (MS). What causes this specific property of being an auto-antigen is still not known. Here we present molecular dynamics simulation studies of unfolding and folding of the protein MOG in both the absence and presence of N-glycan in order to understand the role of glycosylation in the stability and flexibility of the protein. The main results from these studies show that the glycosylation increases the stability of the protein MOG and inhibits the complete unfolding of MOG in the SMD. From the folding studies using TMD, it was observed that the glycan helps the protein to attain the near-native folded conformation. However, it was also observed from the direct TMD studies that the pathway of protein folding was enhanced by the trace-back of intermediate states in the presence of glycan.