Louis Sherman - Academia.edu (original) (raw)
Papers by Louis Sherman
This article cites 48 articles, 20 of which can be accessed free
Proteome analyses of diazotrophic cyanobacteria Cyanothece ATCC 51142 and 1 PCC 7822 under cultur... more Proteome analyses of diazotrophic cyanobacteria Cyanothece ATCC 51142 and 1 PCC 7822 under culture conditions of enhanced H2-production 2 Uma K. Aryal, Stephen J. Callister, Sujata Mishra, Xiaohui Zhang, Janani I. 3 Shutthanandan, Thomas E. Angel, Anil K. Shukla, Matthew E. Monroe, Ronald J. 4 Moore David W. Koppenaal, Richard D. Smith, Louis Sherman 5 6 Pacific Northwest National Laboratory, Richland, WA 99352, USA; Department of 7 Biological Sciences, Purdue University, West Lafayette, IN, USA 8
Molecular BioSystems, 2011
Journal of Bacteriology, 2008
We analyzed the metabolic rhythms and differential gene expression in the unicellular, diazotroph... more We analyzed the metabolic rhythms and differential gene expression in the unicellular, diazotrophic cyanobacterium Cyanothece sp. strain ATCC 51142 under N2-fixing conditions after a shift from normal 12-h light-12-h dark cycles to continuous light. We found that the mRNA levels of ∼10% of the genes in the genome demonstrated circadian behavior during growth in free-running (continuous light) conditions. The genes for N2 fixation displayed a strong circadian behavior, whereas photosynthesis and respiration genes were not as tightly regulated. One of our main objectives was to determine the strategies used by these cells to perform N2 fixation under normal day-night conditions, as well as under the greater stress caused by continuous light. We determined that N2 fixation cycled in continuous light but with a lower N2 fixation activity. Glycogen degradation, respiration, and photosynthesis were also lower; nonetheless, O2 evolution was about 50% of the normal peak. We also demonstrate...
Applied and Environmental Microbiology, 2010
We report on the hydrogen production properties of the unicellular, diazotrophic cyanobacterium C... more We report on the hydrogen production properties of the unicellular, diazotrophic cyanobacterium Cyanothece sp. strain ATCC 51142. This organism has a versatile metabolism and can grow in the presence or absence of combined nitrogen and can grow photosynthetically or mixotrophically and heterotrophically in the presence of glycerol. The strain produces a bidirectional hydrogenase (encoded by the hox genes), an uptake hydrogenase ( hupLS ), and nitrogenase ( nifHDK ). We demonstrated hydrogen production by both the hydrogenase and the nitrogenase under appropriate metabolic conditions. The highest rates of hydrogen production were produced under nitrogen-fixing conditions when cells were grown and incubated under continuous light conditions, in either the presence or absence of glycerol. Under such nitrogen-fixing conditions, we have achieved rates of 300 μmol H 2 /mg chloramphenicol (Chl)/hr during the first 24 h of incubation. The levels of H 2 measured were dependent upon the incub...
ABSTRACT Cultures of the cyanobacterial genus Cyanothece have been shown to produce high levels o... more ABSTRACT Cultures of the cyanobacterial genus Cyanothece have been shown to produce high levels of biohydrogen. These strains are diazotrophic and undergo pronounced diurnal cycles when grown under N(2)-fixing conditions in light-dark cycles. We seek to better understand the way in which proteins respond to these diurnal changes and we performed quantitative proteome analysis of Cyanothece ATCC 51142 and PCC 7822 grown under 8 different nutritional conditions. Nitrogenase expression was limited to N(2)-fixing conditions, and in the absence of glycerol, nitrogenase gene expression was linked to the dark period. However, glycerol induced expression of nitrogenase during part of the light period, together with cytochrome c oxidase (Cox), glycogen phosphorylase (Glp), and glycolytic and pentose-phosphate pathway (PPP) enzymes. This indicated that nitrogenase expression in the light was facilitated via higher respiration and glycogen breakdown. Key enzymes of the Calvin cycle were inhibited in Cyanothece ATCC 51142 in the presence of glycerol under H(2) producing conditions, suggesting a competition between these sources of carbon. However, in Cyanothece PCC 7822, the Calvin cycle still played a role in cofactor recycling during H(2) production. Our data comprise the first comprehensive profiling of proteome changes in Cyanothece PCC 7822, and allows an in-depth comparative analysis of major physiological and biochemical processes that influence H(2)-production in both strains. Our results revealed many previously uncharacterized proteins that may play a role in nitrogenase activity and in other metabolic pathways and may provide suitable targets for genetic manipulation that would lead to improvement of large scale H(2) production.
Applied and Environmental Microbiology, 2012
ABSTRACTCultures of the cyanobacterial genusCyanothecehave been shown to produce high levels of b... more ABSTRACTCultures of the cyanobacterial genusCyanothecehave been shown to produce high levels of biohydrogen. These strains are diazotrophic and undergo pronounced diurnal cycles when grown under N2-fixing conditions in light-dark cycles. We seek to better understand the way in which proteins respond to these diurnal changes, and we performed quantitative proteome analysis ofCyanothecesp. strains ATCC 51142 and PCC 7822 grown under 8 different nutritional conditions. Nitrogenase expression was limited to N2-fixing conditions, and in the absence of glycerol, nitrogenase gene expression was linked to the dark period. However, glycerol induced expression of nitrogenase during part of the light period, together with cytochromecoxidase (Cox), glycogen phosphorylase (Glp), and glycolytic and pentose phosphate pathway (PPP) enzymes. This indicated that nitrogenase expression in the light was facilitated via higher levels of respiration and glycogen breakdown. Key enzymes of the Calvin cycle...
Journal of Bacteriology, 1997
Cyanothece sp. strain ATCC 51142 is a unicellular, diazotrophic cyanobacterium which demonstrated... more Cyanothece sp. strain ATCC 51142 is a unicellular, diazotrophic cyanobacterium which demonstrated extensive metabolic periodicities of photosynthesis, respiration, and nitrogen fixation when grown under N2-fixing conditions. N2 fixation and respiration peaked at 24-h intervals early in the dark or subjective-dark period, whereas photosynthesis was approximately 12 h out of phase and peaked toward the end of the light or subjective-light phase. Gene regulation studies demonstrated that nitrogenase is carefully controlled at the transcriptional and posttranslational levels. Indeed, Cyanothece sp. strain ATCC 51142 has developed an expensive mode of regulation, such that nitrogenase was synthesized and degraded each day. These patterns were seen when cells were grown under either light-dark or continuous-light conditions. Nitrogenase mRNA was synthesized from the nifHDK operon during the first 4 h of the dark period under light-dark conditions or during the first 6 h of the subjective-...
Cultures of the cyanobacterial genus Cyanothece have been shown to produce high levels of biohydr... more Cultures of the cyanobacterial genus Cyanothece have been shown to produce high levels of biohydrogen. These strains are diazotrophic and undergo pronounced diurnal cycles when grown under N 2-fixing conditions in light-dark cycles. We seek to better understand the way in which proteins respond to these diurnal changes, and we performed quantitative proteome analysis of Cyanothece sp. strains ATCC 51142 and PCC 7822 grown under 8 different nutritional conditions. Nitrogenase expression was limited to N 2-fixing conditions, and in the absence of glycerol, nitrogenase gene expression was linked to the dark period. However, glycerol induced expression of nitrogenase during part of the light period, together with cytochrome c oxidase (Cox), glycogen phosphorylase (Glp), and glycolytic and pentose phosphate pathway (PPP) enzymes. This indicated that nitrogenase expression in the light was facilitated via higher levels of respiration and glycogen breakdown. Key enzymes of the Calvin cycle were inhibited in Cyanothece ATCC 51142 in the presence of glycerol under H 2-producing conditions, suggesting a competition between these sources of carbon. However, in Cyanothece PCC 7822, the Calvin cycle still played a role in cofactor recycling during H 2 production. Our data comprise the first comprehensive profiling of proteome changes in Cyanothece PCC 7822 and allow an in-depth comparative analysis of major physiological and biochemical processes that influence H 2 production in both strains. Our results revealed many previously uncharacterized proteins that may play a role in nitrogenase activity and in other metabolic pathways and may provide suitable targets for genetic manipulation that would lead to improvement of large-scale H 2 production.
BMC genomics, Jan 29, 2014
Cyanothece sp. PCC 7822 is an excellent cyanobacterial model organism with great potential to be ... more Cyanothece sp. PCC 7822 is an excellent cyanobacterial model organism with great potential to be applied as a biocatalyst for the production of high value compounds. Like other unicellular diazotrophic cyanobacterial species, it has a tightly regulated metabolism synchronized to the light-dark cycle. Utilizing transcriptomic and proteomic methods, we quantified the relationships between transcription and translation underlying central and secondary metabolism in response to nitrogen free, 12 hour light and 12 hour dark conditions. By combining mass-spectrometry based proteomics and RNA-sequencing transcriptomics, we quantitatively measured a total of 6766 mRNAs and 1322 proteins at four time points across a 24 hour light-dark cycle. Photosynthesis, nitrogen fixation, and carbon storage relevant genes were expressed during the preceding light or dark period, concurrent with measured nitrogenase activity in the late light period. We describe many instances of disparity in peak mRNA an...
Molecular Microbiology, 2014
Journal of Bacteriology, 2015
ABSTRACTCarbohydrate storage is an important element of metabolism in cyanobacteria and in the ch... more ABSTRACTCarbohydrate storage is an important element of metabolism in cyanobacteria and in the chloroplasts of plants. Understanding how to manipulate the metabolism and storage of carbohydrate is also an important factor toward harnessing cyanobacteria for energy production. While most cyanobacteria produce glycogen, some have been found to accumulate polysaccharides in the form of water-insoluble α-glucan similar to amylopectin. Notably, this alternative form, termed “semi-amylopectin,” forms in cyanobacterial species harboring three branching-enzyme (BE) homologs, designated BE1, BE2, and BE3. In this study, mutagenesis of the branching genes found inSynechocystissp. strain PCC 6803 was performed in order to characterize their possible impact on polysaccharide storage granule morphology. N-terminal truncations were made to the native BE gene ofSynechocystissp. PCC 6803. In addition, one of the two native debranching enzyme genes was replaced with a heterologous debranching enzyme...
Virology, May 31, 1976
The importance of photosynthesis in the growth of cyanophage AS-1M in the unicellular blue-green ... more The importance of photosynthesis in the growth of cyanophage AS-1M in the unicellular blue-green alga Synechococcus cedrorum was determined. CO 2 fixation and O 2 evolution continued at high levels throughout the latent period, but decreased rapidly immediately ...
The Journal of Immunology, Jul 1, 1979
Evidence is presented that trinitrophenyl-coupled tumor membranes are able to induce cytolytic T ... more Evidence is presented that trinitrophenyl-coupled tumor membranes are able to induce cytolytic T lymphocytes (CTL) when co-cultured with syngeneic spleen cells. These haptenated membranes stimulate spleen cells from naive and immune mice. The specificity of these CTL is determined by the H-2 antigens of the membranes used for stimulation.
Journal of Bacteriology, Feb 1, 1998
Biochemistry Usa, 1991
The photosystem I1 (PSII) reaction center complex coordinates a cluster of M n atoms that are inv... more The photosystem I1 (PSII) reaction center complex coordinates a cluster of M n atoms that are involved in the accumulation of oxidizing equivalents generated by light-induced charge separations within the intrinsic portion of the PSII complex. A 33-kDa extrinsic protein, termed the Mn-stabilizing protein (MSP), has been implicated in the stabilization of two of the four Mn atoms of the cluster, yet the precise role of this protein in 0, evolution remains to be elucidated. Here we describe the construction of a mutant of the cyanobacterium Synechocystis sp. PCC6803 in which the entire gene encoding MSP has been deleted. Northern and immunoblot analyses indicate that other PSII proteins are expressed and accumulated, despite the absence of MSP. Fluorescence emission spectra at 77 K indicate PSII assembles in the mutant, but that the binding of M S P is required for the normal fluorescence characteristics of the PSII complex, and suggest a specific interaction between MSP and CP47. Fluorescence induction measurements indicate a reduced rate of forward electron transport to the primary electron donor, P680, in the mutant. It is concluded
Biochemistry, Feb 1, 1991
The photosystem I1 (PSII) reaction center complex coordinates a cluster of M n atoms that are inv... more The photosystem I1 (PSII) reaction center complex coordinates a cluster of M n atoms that are involved in the accumulation of oxidizing equivalents generated by light-induced charge separations within the intrinsic portion of the PSII complex. A 33-kDa extrinsic protein, termed the Mn-stabilizing protein (MSP), has been implicated in the stabilization of two of the four Mn atoms of the cluster, yet the precise role of this protein in 0, evolution remains to be elucidated. Here we describe the construction of a mutant of the cyanobacterium Synechocystis sp. PCC6803 in which the entire gene encoding MSP has been deleted. Northern and immunoblot analyses indicate that other PSII proteins are expressed and accumulated, despite the absence of MSP. Fluorescence emission spectra at 77 K indicate PSII assembles in the mutant, but that the binding of M S P is required for the normal fluorescence characteristics of the PSII complex, and suggest a specific interaction between MSP and CP47. Fluorescence induction measurements indicate a reduced rate of forward electron transport to the primary electron donor, P680, in the mutant. It is concluded
This article cites 48 articles, 20 of which can be accessed free
Proteome analyses of diazotrophic cyanobacteria Cyanothece ATCC 51142 and 1 PCC 7822 under cultur... more Proteome analyses of diazotrophic cyanobacteria Cyanothece ATCC 51142 and 1 PCC 7822 under culture conditions of enhanced H2-production 2 Uma K. Aryal, Stephen J. Callister, Sujata Mishra, Xiaohui Zhang, Janani I. 3 Shutthanandan, Thomas E. Angel, Anil K. Shukla, Matthew E. Monroe, Ronald J. 4 Moore David W. Koppenaal, Richard D. Smith, Louis Sherman 5 6 Pacific Northwest National Laboratory, Richland, WA 99352, USA; Department of 7 Biological Sciences, Purdue University, West Lafayette, IN, USA 8
Molecular BioSystems, 2011
Journal of Bacteriology, 2008
We analyzed the metabolic rhythms and differential gene expression in the unicellular, diazotroph... more We analyzed the metabolic rhythms and differential gene expression in the unicellular, diazotrophic cyanobacterium Cyanothece sp. strain ATCC 51142 under N2-fixing conditions after a shift from normal 12-h light-12-h dark cycles to continuous light. We found that the mRNA levels of ∼10% of the genes in the genome demonstrated circadian behavior during growth in free-running (continuous light) conditions. The genes for N2 fixation displayed a strong circadian behavior, whereas photosynthesis and respiration genes were not as tightly regulated. One of our main objectives was to determine the strategies used by these cells to perform N2 fixation under normal day-night conditions, as well as under the greater stress caused by continuous light. We determined that N2 fixation cycled in continuous light but with a lower N2 fixation activity. Glycogen degradation, respiration, and photosynthesis were also lower; nonetheless, O2 evolution was about 50% of the normal peak. We also demonstrate...
Applied and Environmental Microbiology, 2010
We report on the hydrogen production properties of the unicellular, diazotrophic cyanobacterium C... more We report on the hydrogen production properties of the unicellular, diazotrophic cyanobacterium Cyanothece sp. strain ATCC 51142. This organism has a versatile metabolism and can grow in the presence or absence of combined nitrogen and can grow photosynthetically or mixotrophically and heterotrophically in the presence of glycerol. The strain produces a bidirectional hydrogenase (encoded by the hox genes), an uptake hydrogenase ( hupLS ), and nitrogenase ( nifHDK ). We demonstrated hydrogen production by both the hydrogenase and the nitrogenase under appropriate metabolic conditions. The highest rates of hydrogen production were produced under nitrogen-fixing conditions when cells were grown and incubated under continuous light conditions, in either the presence or absence of glycerol. Under such nitrogen-fixing conditions, we have achieved rates of 300 μmol H 2 /mg chloramphenicol (Chl)/hr during the first 24 h of incubation. The levels of H 2 measured were dependent upon the incub...
ABSTRACT Cultures of the cyanobacterial genus Cyanothece have been shown to produce high levels o... more ABSTRACT Cultures of the cyanobacterial genus Cyanothece have been shown to produce high levels of biohydrogen. These strains are diazotrophic and undergo pronounced diurnal cycles when grown under N(2)-fixing conditions in light-dark cycles. We seek to better understand the way in which proteins respond to these diurnal changes and we performed quantitative proteome analysis of Cyanothece ATCC 51142 and PCC 7822 grown under 8 different nutritional conditions. Nitrogenase expression was limited to N(2)-fixing conditions, and in the absence of glycerol, nitrogenase gene expression was linked to the dark period. However, glycerol induced expression of nitrogenase during part of the light period, together with cytochrome c oxidase (Cox), glycogen phosphorylase (Glp), and glycolytic and pentose-phosphate pathway (PPP) enzymes. This indicated that nitrogenase expression in the light was facilitated via higher respiration and glycogen breakdown. Key enzymes of the Calvin cycle were inhibited in Cyanothece ATCC 51142 in the presence of glycerol under H(2) producing conditions, suggesting a competition between these sources of carbon. However, in Cyanothece PCC 7822, the Calvin cycle still played a role in cofactor recycling during H(2) production. Our data comprise the first comprehensive profiling of proteome changes in Cyanothece PCC 7822, and allows an in-depth comparative analysis of major physiological and biochemical processes that influence H(2)-production in both strains. Our results revealed many previously uncharacterized proteins that may play a role in nitrogenase activity and in other metabolic pathways and may provide suitable targets for genetic manipulation that would lead to improvement of large scale H(2) production.
Applied and Environmental Microbiology, 2012
ABSTRACTCultures of the cyanobacterial genusCyanothecehave been shown to produce high levels of b... more ABSTRACTCultures of the cyanobacterial genusCyanothecehave been shown to produce high levels of biohydrogen. These strains are diazotrophic and undergo pronounced diurnal cycles when grown under N2-fixing conditions in light-dark cycles. We seek to better understand the way in which proteins respond to these diurnal changes, and we performed quantitative proteome analysis ofCyanothecesp. strains ATCC 51142 and PCC 7822 grown under 8 different nutritional conditions. Nitrogenase expression was limited to N2-fixing conditions, and in the absence of glycerol, nitrogenase gene expression was linked to the dark period. However, glycerol induced expression of nitrogenase during part of the light period, together with cytochromecoxidase (Cox), glycogen phosphorylase (Glp), and glycolytic and pentose phosphate pathway (PPP) enzymes. This indicated that nitrogenase expression in the light was facilitated via higher levels of respiration and glycogen breakdown. Key enzymes of the Calvin cycle...
Journal of Bacteriology, 1997
Cyanothece sp. strain ATCC 51142 is a unicellular, diazotrophic cyanobacterium which demonstrated... more Cyanothece sp. strain ATCC 51142 is a unicellular, diazotrophic cyanobacterium which demonstrated extensive metabolic periodicities of photosynthesis, respiration, and nitrogen fixation when grown under N2-fixing conditions. N2 fixation and respiration peaked at 24-h intervals early in the dark or subjective-dark period, whereas photosynthesis was approximately 12 h out of phase and peaked toward the end of the light or subjective-light phase. Gene regulation studies demonstrated that nitrogenase is carefully controlled at the transcriptional and posttranslational levels. Indeed, Cyanothece sp. strain ATCC 51142 has developed an expensive mode of regulation, such that nitrogenase was synthesized and degraded each day. These patterns were seen when cells were grown under either light-dark or continuous-light conditions. Nitrogenase mRNA was synthesized from the nifHDK operon during the first 4 h of the dark period under light-dark conditions or during the first 6 h of the subjective-...
Cultures of the cyanobacterial genus Cyanothece have been shown to produce high levels of biohydr... more Cultures of the cyanobacterial genus Cyanothece have been shown to produce high levels of biohydrogen. These strains are diazotrophic and undergo pronounced diurnal cycles when grown under N 2-fixing conditions in light-dark cycles. We seek to better understand the way in which proteins respond to these diurnal changes, and we performed quantitative proteome analysis of Cyanothece sp. strains ATCC 51142 and PCC 7822 grown under 8 different nutritional conditions. Nitrogenase expression was limited to N 2-fixing conditions, and in the absence of glycerol, nitrogenase gene expression was linked to the dark period. However, glycerol induced expression of nitrogenase during part of the light period, together with cytochrome c oxidase (Cox), glycogen phosphorylase (Glp), and glycolytic and pentose phosphate pathway (PPP) enzymes. This indicated that nitrogenase expression in the light was facilitated via higher levels of respiration and glycogen breakdown. Key enzymes of the Calvin cycle were inhibited in Cyanothece ATCC 51142 in the presence of glycerol under H 2-producing conditions, suggesting a competition between these sources of carbon. However, in Cyanothece PCC 7822, the Calvin cycle still played a role in cofactor recycling during H 2 production. Our data comprise the first comprehensive profiling of proteome changes in Cyanothece PCC 7822 and allow an in-depth comparative analysis of major physiological and biochemical processes that influence H 2 production in both strains. Our results revealed many previously uncharacterized proteins that may play a role in nitrogenase activity and in other metabolic pathways and may provide suitable targets for genetic manipulation that would lead to improvement of large-scale H 2 production.
BMC genomics, Jan 29, 2014
Cyanothece sp. PCC 7822 is an excellent cyanobacterial model organism with great potential to be ... more Cyanothece sp. PCC 7822 is an excellent cyanobacterial model organism with great potential to be applied as a biocatalyst for the production of high value compounds. Like other unicellular diazotrophic cyanobacterial species, it has a tightly regulated metabolism synchronized to the light-dark cycle. Utilizing transcriptomic and proteomic methods, we quantified the relationships between transcription and translation underlying central and secondary metabolism in response to nitrogen free, 12 hour light and 12 hour dark conditions. By combining mass-spectrometry based proteomics and RNA-sequencing transcriptomics, we quantitatively measured a total of 6766 mRNAs and 1322 proteins at four time points across a 24 hour light-dark cycle. Photosynthesis, nitrogen fixation, and carbon storage relevant genes were expressed during the preceding light or dark period, concurrent with measured nitrogenase activity in the late light period. We describe many instances of disparity in peak mRNA an...
Molecular Microbiology, 2014
Journal of Bacteriology, 2015
ABSTRACTCarbohydrate storage is an important element of metabolism in cyanobacteria and in the ch... more ABSTRACTCarbohydrate storage is an important element of metabolism in cyanobacteria and in the chloroplasts of plants. Understanding how to manipulate the metabolism and storage of carbohydrate is also an important factor toward harnessing cyanobacteria for energy production. While most cyanobacteria produce glycogen, some have been found to accumulate polysaccharides in the form of water-insoluble α-glucan similar to amylopectin. Notably, this alternative form, termed “semi-amylopectin,” forms in cyanobacterial species harboring three branching-enzyme (BE) homologs, designated BE1, BE2, and BE3. In this study, mutagenesis of the branching genes found inSynechocystissp. strain PCC 6803 was performed in order to characterize their possible impact on polysaccharide storage granule morphology. N-terminal truncations were made to the native BE gene ofSynechocystissp. PCC 6803. In addition, one of the two native debranching enzyme genes was replaced with a heterologous debranching enzyme...
Virology, May 31, 1976
The importance of photosynthesis in the growth of cyanophage AS-1M in the unicellular blue-green ... more The importance of photosynthesis in the growth of cyanophage AS-1M in the unicellular blue-green alga Synechococcus cedrorum was determined. CO 2 fixation and O 2 evolution continued at high levels throughout the latent period, but decreased rapidly immediately ...
The Journal of Immunology, Jul 1, 1979
Evidence is presented that trinitrophenyl-coupled tumor membranes are able to induce cytolytic T ... more Evidence is presented that trinitrophenyl-coupled tumor membranes are able to induce cytolytic T lymphocytes (CTL) when co-cultured with syngeneic spleen cells. These haptenated membranes stimulate spleen cells from naive and immune mice. The specificity of these CTL is determined by the H-2 antigens of the membranes used for stimulation.
Journal of Bacteriology, Feb 1, 1998
Biochemistry Usa, 1991
The photosystem I1 (PSII) reaction center complex coordinates a cluster of M n atoms that are inv... more The photosystem I1 (PSII) reaction center complex coordinates a cluster of M n atoms that are involved in the accumulation of oxidizing equivalents generated by light-induced charge separations within the intrinsic portion of the PSII complex. A 33-kDa extrinsic protein, termed the Mn-stabilizing protein (MSP), has been implicated in the stabilization of two of the four Mn atoms of the cluster, yet the precise role of this protein in 0, evolution remains to be elucidated. Here we describe the construction of a mutant of the cyanobacterium Synechocystis sp. PCC6803 in which the entire gene encoding MSP has been deleted. Northern and immunoblot analyses indicate that other PSII proteins are expressed and accumulated, despite the absence of MSP. Fluorescence emission spectra at 77 K indicate PSII assembles in the mutant, but that the binding of M S P is required for the normal fluorescence characteristics of the PSII complex, and suggest a specific interaction between MSP and CP47. Fluorescence induction measurements indicate a reduced rate of forward electron transport to the primary electron donor, P680, in the mutant. It is concluded
Biochemistry, Feb 1, 1991
The photosystem I1 (PSII) reaction center complex coordinates a cluster of M n atoms that are inv... more The photosystem I1 (PSII) reaction center complex coordinates a cluster of M n atoms that are involved in the accumulation of oxidizing equivalents generated by light-induced charge separations within the intrinsic portion of the PSII complex. A 33-kDa extrinsic protein, termed the Mn-stabilizing protein (MSP), has been implicated in the stabilization of two of the four Mn atoms of the cluster, yet the precise role of this protein in 0, evolution remains to be elucidated. Here we describe the construction of a mutant of the cyanobacterium Synechocystis sp. PCC6803 in which the entire gene encoding MSP has been deleted. Northern and immunoblot analyses indicate that other PSII proteins are expressed and accumulated, despite the absence of MSP. Fluorescence emission spectra at 77 K indicate PSII assembles in the mutant, but that the binding of M S P is required for the normal fluorescence characteristics of the PSII complex, and suggest a specific interaction between MSP and CP47. Fluorescence induction measurements indicate a reduced rate of forward electron transport to the primary electron donor, P680, in the mutant. It is concluded