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Paula Tamagnini - One of the best experts on this subject based on the ideXlab platform.
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Cyanobacterial Hydrogenases: diversity, regulation and applications
FEMS microbiology reviews, 2007Co-Authors: Paula Tamagnini, Elsa Leitão, Daniela Ferreira, Filipe Pinto, Paulo J. Oliveira, David James Harris, Thorsten Heidorn, Peter LindbladAbstract:Cyanobacteria may possess two distinct nickel-iron (NiFe)-Hydrogenases: an uptake enzyme found in N(2)-fixing strains, and a bidirectional one present in both non-N(2)-fixing and N(2)-fixing strains. The uptake Hydrogenase (encoded by hupSL) catalyzes the consumption of the H(2) produced during N(2) fixation, while the bidirectional enzyme (hoxEFUYH) probably plays a role in fermentation and/or acts as an electron valve during photosynthesis. hupSL constitute a transcriptional unit, and are essentially transcribed under N(2)-fixing conditions. The bidirectional Hydrogenase consists of a Hydrogenase and a diaphorase part, and the corresponding five hox genes are not always clustered or cotranscribed. The biosynthesis/maturation of NiFe-Hydrogenases is highly complex, requiring several core proteins. In cyanobacteria, the genes that are thought to affect Hydrogenases pleiotropically (hyp), as well as the genes presumably encoding the Hydrogenase-specific endopeptidases (hupW and hoxW) have been identified and characterized. Furthermore, NtcA and LexA have been implicated in the transcriptional regulation of the uptake and the bidirectional enzyme respectively. Recently, the phylogenetic origin of cyanobacterial and algal Hydrogenases was analyzed, and it was proposed that the current distribution in cyanobacteria reflects a differential loss of genes according to their ecological needs or constraints. In addition, the possibilities and challenges of cyanobacterial-based H(2) production are addressed.
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genes involved in the maturation of Hydrogenase s in the nonheterocystous cyanobacterium lyngbya majuscula ccap 1446 4
International Journal of Hydrogen Energy, 2006Co-Authors: Elsa Leitão, Pedro Moradasferreira, Daniela Ferreira, Filipe Pinto, Sara Pereira, Joana Bondoso, Paula TamagniniAbstract:Abstract Lyngbya majuscula CCAP 1446/4 is a N 2 -fixing filamentous nonheterocystous cyanobacterium that possesses two NiFe Hydrogenases: an uptake and a bidirectional Hydrogenase. The biosynthesis/maturation of NiFe Hydrogenases is a highly complex process requiring several proteins. This work presents the characterization of the hyp cluster in L. majuscula . The hyp genes are located ca. 8 kb upstream from the uptake Hydrogenase structural genes, and seem to be transcribed as a single operon, including three other ORFs interspersed throughout the cluster. In addition, the transcriptional start point was identified 21 bp upstream of hypF , and regulatory sequences were recognized within the promoter region. Several ORFs could also be discerned between the hup and the hyp genes. Moreover, hupW , the gene encoding the putative uptake Hydrogenase C-terminal endopeptidase was found 1102 bp downstream of hupL . The Hydrogenases maturation process and its regulation are discussed for cyanobacteria possessing both or just one Hydrogenase.
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Genes involved in the maturation of Hydrogenase(s) in the nonheterocystous cyanobacterium Lyngbya majuscula CCAP 1446/4
International Journal of Hydrogen Energy, 2006Co-Authors: Elsa Leitão, Pedro Moradas-ferreira, Daniela Ferreira, Filipe Pinto, Sara Pereira, Joana Bondoso, Paula TamagniniAbstract:Abstract Lyngbya majuscula CCAP 1446/4 is a N 2 -fixing filamentous nonheterocystous cyanobacterium that possesses two NiFe Hydrogenases: an uptake and a bidirectional Hydrogenase. The biosynthesis/maturation of NiFe Hydrogenases is a highly complex process requiring several proteins. This work presents the characterization of the hyp cluster in L. majuscula . The hyp genes are located ca. 8 kb upstream from the uptake Hydrogenase structural genes, and seem to be transcribed as a single operon, including three other ORFs interspersed throughout the cluster. In addition, the transcriptional start point was identified 21 bp upstream of hypF , and regulatory sequences were recognized within the promoter region. Several ORFs could also be discerned between the hup and the hyp genes. Moreover, hupW , the gene encoding the putative uptake Hydrogenase C-terminal endopeptidase was found 1102 bp downstream of hupL . The Hydrogenases maturation process and its regulation are discussed for cyanobacteria possessing both or just one Hydrogenase.
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Diversity of Cyanobacterial Hydrogenases, a Molecular Approach
Current microbiology, 2000Co-Authors: Paula Tamagnini, José-luís Costa, Lígia Almeida, Maria-josé Oliveira, Roberto Salema, Peter LindbladAbstract:In an effort to elucidate the diversity of cyanobacterial Hydrogenases, we used a molecular approach. Filamentous strains from a broad range of sources were screened for the presence of hup (uptake Hydrogenase), xisC (rearrangement within hupL), and hox (bidirectional Hydrogenase) genes. As expected, an uptake Hydrogenase seems to be present in all N2-fixing cyanobacteria. On the other hand, no evidence was found for the presence of a conventional bidirectional enzyme in several strains. Similarly, the presence of xisC is not a characteristic shared by all the heterocyst-forming cyanobacteria. Although tempting, it is not possible to establish a correlation between the presence/absence of the bidirectional Hydrogenase and the occurrence of xisC. The natural molecular variation of Hydrogenases in cyanobacteria is certainly a field to explore, both to understand the physiological functions of the respective enzymes and to identify a genetic background to be used when constructing a strain for photobiological H2 production in a bioreactor.
Elsa Leitão - One of the best experts on this subject based on the ideXlab platform.
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Cyanobacterial Hydrogenases: diversity, regulation and applications
FEMS microbiology reviews, 2007Co-Authors: Paula Tamagnini, Elsa Leitão, Daniela Ferreira, Filipe Pinto, Paulo J. Oliveira, David James Harris, Thorsten Heidorn, Peter LindbladAbstract:Cyanobacteria may possess two distinct nickel-iron (NiFe)-Hydrogenases: an uptake enzyme found in N(2)-fixing strains, and a bidirectional one present in both non-N(2)-fixing and N(2)-fixing strains. The uptake Hydrogenase (encoded by hupSL) catalyzes the consumption of the H(2) produced during N(2) fixation, while the bidirectional enzyme (hoxEFUYH) probably plays a role in fermentation and/or acts as an electron valve during photosynthesis. hupSL constitute a transcriptional unit, and are essentially transcribed under N(2)-fixing conditions. The bidirectional Hydrogenase consists of a Hydrogenase and a diaphorase part, and the corresponding five hox genes are not always clustered or cotranscribed. The biosynthesis/maturation of NiFe-Hydrogenases is highly complex, requiring several core proteins. In cyanobacteria, the genes that are thought to affect Hydrogenases pleiotropically (hyp), as well as the genes presumably encoding the Hydrogenase-specific endopeptidases (hupW and hoxW) have been identified and characterized. Furthermore, NtcA and LexA have been implicated in the transcriptional regulation of the uptake and the bidirectional enzyme respectively. Recently, the phylogenetic origin of cyanobacterial and algal Hydrogenases was analyzed, and it was proposed that the current distribution in cyanobacteria reflects a differential loss of genes according to their ecological needs or constraints. In addition, the possibilities and challenges of cyanobacterial-based H(2) production are addressed.
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genes involved in the maturation of Hydrogenase s in the nonheterocystous cyanobacterium lyngbya majuscula ccap 1446 4
International Journal of Hydrogen Energy, 2006Co-Authors: Elsa Leitão, Pedro Moradasferreira, Daniela Ferreira, Filipe Pinto, Sara Pereira, Joana Bondoso, Paula TamagniniAbstract:Abstract Lyngbya majuscula CCAP 1446/4 is a N 2 -fixing filamentous nonheterocystous cyanobacterium that possesses two NiFe Hydrogenases: an uptake and a bidirectional Hydrogenase. The biosynthesis/maturation of NiFe Hydrogenases is a highly complex process requiring several proteins. This work presents the characterization of the hyp cluster in L. majuscula . The hyp genes are located ca. 8 kb upstream from the uptake Hydrogenase structural genes, and seem to be transcribed as a single operon, including three other ORFs interspersed throughout the cluster. In addition, the transcriptional start point was identified 21 bp upstream of hypF , and regulatory sequences were recognized within the promoter region. Several ORFs could also be discerned between the hup and the hyp genes. Moreover, hupW , the gene encoding the putative uptake Hydrogenase C-terminal endopeptidase was found 1102 bp downstream of hupL . The Hydrogenases maturation process and its regulation are discussed for cyanobacteria possessing both or just one Hydrogenase.
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Genes involved in the maturation of Hydrogenase(s) in the nonheterocystous cyanobacterium Lyngbya majuscula CCAP 1446/4
International Journal of Hydrogen Energy, 2006Co-Authors: Elsa Leitão, Pedro Moradas-ferreira, Daniela Ferreira, Filipe Pinto, Sara Pereira, Joana Bondoso, Paula TamagniniAbstract:Abstract Lyngbya majuscula CCAP 1446/4 is a N 2 -fixing filamentous nonheterocystous cyanobacterium that possesses two NiFe Hydrogenases: an uptake and a bidirectional Hydrogenase. The biosynthesis/maturation of NiFe Hydrogenases is a highly complex process requiring several proteins. This work presents the characterization of the hyp cluster in L. majuscula . The hyp genes are located ca. 8 kb upstream from the uptake Hydrogenase structural genes, and seem to be transcribed as a single operon, including three other ORFs interspersed throughout the cluster. In addition, the transcriptional start point was identified 21 bp upstream of hypF , and regulatory sequences were recognized within the promoter region. Several ORFs could also be discerned between the hup and the hyp genes. Moreover, hupW , the gene encoding the putative uptake Hydrogenase C-terminal endopeptidase was found 1102 bp downstream of hupL . The Hydrogenases maturation process and its regulation are discussed for cyanobacteria possessing both or just one Hydrogenase.
Peter Lindblad - One of the best experts on this subject based on the ideXlab platform.
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Transcript analysis of the extended hyp -operon in the cyanobacteria Nostoc sp. strain PCC 7120 and Nostoc punctiforme ATCC 29133
BMC research notes, 2011Co-Authors: Marie Holmqvist, Karin Stensjö, Pia Lindberg, Åsa Agervald, Peter LindbladAbstract:Background Cyanobacteria harbor two [NiFe]-type Hydrogenases consisting of a large and a small subunit, the Hup- and Hox-Hydrogenase, respectively. Insertion of ligands and correct folding of nickel-iron Hydrogenases require assistance of accessory maturation proteins (encoded by the hyp-genes). The intergenic region between the structural genes encoding the uptake Hydrogenase (hupSL) and the accessory maturation proteins (hyp genes) in the cyanobacteria Nostoc PCC 7120 and N. punctiforme were analysed using molecular methods.
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Diversity and transcription of proteases involved in the maturation of Hydrogenases in Nostoc punctiforme ATCC 29133 and Nostoc sp. strain PCC 7120
BMC Microbiology, 2009Co-Authors: Ellenor Devine, Marie Holmqvist, Karin Stensjö, Peter LindbladAbstract:Background The last step in the maturation process of the large subunit of [NiFe]-Hydrogenases is a proteolytic cleavage of the C-terminal by a Hydrogenase specific protease. Contrary to other accessory proteins these Hydrogenase proteases are believed to be specific whereby one type of Hydrogenases specific protease only cleaves one type of Hydrogenase. In cyanobacteria this is achieved by the gene product of either hupW or hoxW, specific for the uptake or the bidirectional Hydrogenase respectively. The filamentous cyanobacteria Nostoc punctiforme ATCC 29133 and Nostoc sp strain PCC 7120 may contain a single uptake Hydrogenase or both an uptake and a bidirectional Hydrogenase respectively.
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Cyanobacterial Hydrogenases: diversity, regulation and applications
FEMS microbiology reviews, 2007Co-Authors: Paula Tamagnini, Elsa Leitão, Daniela Ferreira, Filipe Pinto, Paulo J. Oliveira, David James Harris, Thorsten Heidorn, Peter LindbladAbstract:Cyanobacteria may possess two distinct nickel-iron (NiFe)-Hydrogenases: an uptake enzyme found in N(2)-fixing strains, and a bidirectional one present in both non-N(2)-fixing and N(2)-fixing strains. The uptake Hydrogenase (encoded by hupSL) catalyzes the consumption of the H(2) produced during N(2) fixation, while the bidirectional enzyme (hoxEFUYH) probably plays a role in fermentation and/or acts as an electron valve during photosynthesis. hupSL constitute a transcriptional unit, and are essentially transcribed under N(2)-fixing conditions. The bidirectional Hydrogenase consists of a Hydrogenase and a diaphorase part, and the corresponding five hox genes are not always clustered or cotranscribed. The biosynthesis/maturation of NiFe-Hydrogenases is highly complex, requiring several core proteins. In cyanobacteria, the genes that are thought to affect Hydrogenases pleiotropically (hyp), as well as the genes presumably encoding the Hydrogenase-specific endopeptidases (hupW and hoxW) have been identified and characterized. Furthermore, NtcA and LexA have been implicated in the transcriptional regulation of the uptake and the bidirectional enzyme respectively. Recently, the phylogenetic origin of cyanobacterial and algal Hydrogenases was analyzed, and it was proposed that the current distribution in cyanobacteria reflects a differential loss of genes according to their ecological needs or constraints. In addition, the possibilities and challenges of cyanobacterial-based H(2) production are addressed.
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Presence and expression of Hydrogenase specific C-terminal endopeptidases in cyanobacteria
BMC Microbiology, 2003Co-Authors: Röbbe Wünschiers, Mehtap Batur, Peter LindbladAbstract:Background Hydrogenases catalyze the simplest of all chemical reactions: the reduction of protons to molecular hydrogen or vice versa . Cyanobacteria can express an uptake, a bidirectional or both NiFe-Hydrogenases. Maturation of those depends on accessory proteins encoded by hyp -genes. The last maturation step involves the cleavage of a ca. 30 amino acid long peptide from the large subunit by a C-terminal endopeptidase. Until know, nothing is known about the maturation of cyanobacterial NiFe-Hydrogenases. The availability of three complete cyanobacterial genome sequences from strains with either only the uptake ( Nostoc punctiforme ATCC 29133/PCC 73102), only the bidirectional ( Synechocystis PCC 6803) or both NiFe-Hydrogenases ( Anabaena PCC 7120) prompted us to mine these genomes for Hydrogenase maturation related genes. In this communication we focus on the presence and the expression of the NiFe-Hydrogenases and the corresponding C-terminal endopeptidases, in the three strains mentioned above. Results We identified genes encoding putative cyanobacterial Hydrogenase specific C-terminal endopeptidases in all analyzed cyanobacterial genomes. The genes are not part of any known Hydrogenase related gene cluster. The derived amino acid sequences show only low similarity (28–41%) to the well-analyzed Hydrogenase specific C-terminal endopeptidase HybD from Escherichia coli , the crystal structure of which is known. However, computational secondary and tertiary structure modeling revealed the presence of conserved structural patterns around the highly conserved active site. Gene expression analysis shows that the endopeptidase encoding genes are expressed under both nitrogen-fixing and non-nitrogen-fixing conditions. Conclusion Anabaena PCC 7120 possesses two NiFe-Hydrogenases and two Hydrogenase specific C-terminal endopeptidases but only one set of hyp -genes. Thus, in contrast to the Hyp-proteins, the C-terminal endopeptidases are the only known Hydrogenase maturation factors that are specific. Therefore, in accordance with previous nomenclature, we propose the gene names hoxW and hupW for the bidirectional and uptake Hydrogenase processing endopeptidases, respectively. Due to their constitutive expression we expect that, at least in cyanobacteria, the endopeptidases take over multiple functions.
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Diversity of Cyanobacterial Hydrogenases, a Molecular Approach
Current microbiology, 2000Co-Authors: Paula Tamagnini, José-luís Costa, Lígia Almeida, Maria-josé Oliveira, Roberto Salema, Peter LindbladAbstract:In an effort to elucidate the diversity of cyanobacterial Hydrogenases, we used a molecular approach. Filamentous strains from a broad range of sources were screened for the presence of hup (uptake Hydrogenase), xisC (rearrangement within hupL), and hox (bidirectional Hydrogenase) genes. As expected, an uptake Hydrogenase seems to be present in all N2-fixing cyanobacteria. On the other hand, no evidence was found for the presence of a conventional bidirectional enzyme in several strains. Similarly, the presence of xisC is not a characteristic shared by all the heterocyst-forming cyanobacteria. Although tempting, it is not possible to establish a correlation between the presence/absence of the bidirectional Hydrogenase and the occurrence of xisC. The natural molecular variation of Hydrogenases in cyanobacteria is certainly a field to explore, both to understand the physiological functions of the respective enzymes and to identify a genetic background to be used when constructing a strain for photobiological H2 production in a bioreactor.
Filipe Pinto - One of the best experts on this subject based on the ideXlab platform.
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Cyanobacterial Hydrogenases: diversity, regulation and applications
FEMS microbiology reviews, 2007Co-Authors: Paula Tamagnini, Elsa Leitão, Daniela Ferreira, Filipe Pinto, Paulo J. Oliveira, David James Harris, Thorsten Heidorn, Peter LindbladAbstract:Cyanobacteria may possess two distinct nickel-iron (NiFe)-Hydrogenases: an uptake enzyme found in N(2)-fixing strains, and a bidirectional one present in both non-N(2)-fixing and N(2)-fixing strains. The uptake Hydrogenase (encoded by hupSL) catalyzes the consumption of the H(2) produced during N(2) fixation, while the bidirectional enzyme (hoxEFUYH) probably plays a role in fermentation and/or acts as an electron valve during photosynthesis. hupSL constitute a transcriptional unit, and are essentially transcribed under N(2)-fixing conditions. The bidirectional Hydrogenase consists of a Hydrogenase and a diaphorase part, and the corresponding five hox genes are not always clustered or cotranscribed. The biosynthesis/maturation of NiFe-Hydrogenases is highly complex, requiring several core proteins. In cyanobacteria, the genes that are thought to affect Hydrogenases pleiotropically (hyp), as well as the genes presumably encoding the Hydrogenase-specific endopeptidases (hupW and hoxW) have been identified and characterized. Furthermore, NtcA and LexA have been implicated in the transcriptional regulation of the uptake and the bidirectional enzyme respectively. Recently, the phylogenetic origin of cyanobacterial and algal Hydrogenases was analyzed, and it was proposed that the current distribution in cyanobacteria reflects a differential loss of genes according to their ecological needs or constraints. In addition, the possibilities and challenges of cyanobacterial-based H(2) production are addressed.
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genes involved in the maturation of Hydrogenase s in the nonheterocystous cyanobacterium lyngbya majuscula ccap 1446 4
International Journal of Hydrogen Energy, 2006Co-Authors: Elsa Leitão, Pedro Moradasferreira, Daniela Ferreira, Filipe Pinto, Sara Pereira, Joana Bondoso, Paula TamagniniAbstract:Abstract Lyngbya majuscula CCAP 1446/4 is a N 2 -fixing filamentous nonheterocystous cyanobacterium that possesses two NiFe Hydrogenases: an uptake and a bidirectional Hydrogenase. The biosynthesis/maturation of NiFe Hydrogenases is a highly complex process requiring several proteins. This work presents the characterization of the hyp cluster in L. majuscula . The hyp genes are located ca. 8 kb upstream from the uptake Hydrogenase structural genes, and seem to be transcribed as a single operon, including three other ORFs interspersed throughout the cluster. In addition, the transcriptional start point was identified 21 bp upstream of hypF , and regulatory sequences were recognized within the promoter region. Several ORFs could also be discerned between the hup and the hyp genes. Moreover, hupW , the gene encoding the putative uptake Hydrogenase C-terminal endopeptidase was found 1102 bp downstream of hupL . The Hydrogenases maturation process and its regulation are discussed for cyanobacteria possessing both or just one Hydrogenase.
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Genes involved in the maturation of Hydrogenase(s) in the nonheterocystous cyanobacterium Lyngbya majuscula CCAP 1446/4
International Journal of Hydrogen Energy, 2006Co-Authors: Elsa Leitão, Pedro Moradas-ferreira, Daniela Ferreira, Filipe Pinto, Sara Pereira, Joana Bondoso, Paula TamagniniAbstract:Abstract Lyngbya majuscula CCAP 1446/4 is a N 2 -fixing filamentous nonheterocystous cyanobacterium that possesses two NiFe Hydrogenases: an uptake and a bidirectional Hydrogenase. The biosynthesis/maturation of NiFe Hydrogenases is a highly complex process requiring several proteins. This work presents the characterization of the hyp cluster in L. majuscula . The hyp genes are located ca. 8 kb upstream from the uptake Hydrogenase structural genes, and seem to be transcribed as a single operon, including three other ORFs interspersed throughout the cluster. In addition, the transcriptional start point was identified 21 bp upstream of hypF , and regulatory sequences were recognized within the promoter region. Several ORFs could also be discerned between the hup and the hyp genes. Moreover, hupW , the gene encoding the putative uptake Hydrogenase C-terminal endopeptidase was found 1102 bp downstream of hupL . The Hydrogenases maturation process and its regulation are discussed for cyanobacteria possessing both or just one Hydrogenase.
Daniela Ferreira - One of the best experts on this subject based on the ideXlab platform.
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Cyanobacterial Hydrogenases: diversity, regulation and applications
FEMS microbiology reviews, 2007Co-Authors: Paula Tamagnini, Elsa Leitão, Daniela Ferreira, Filipe Pinto, Paulo J. Oliveira, David James Harris, Thorsten Heidorn, Peter LindbladAbstract:Cyanobacteria may possess two distinct nickel-iron (NiFe)-Hydrogenases: an uptake enzyme found in N(2)-fixing strains, and a bidirectional one present in both non-N(2)-fixing and N(2)-fixing strains. The uptake Hydrogenase (encoded by hupSL) catalyzes the consumption of the H(2) produced during N(2) fixation, while the bidirectional enzyme (hoxEFUYH) probably plays a role in fermentation and/or acts as an electron valve during photosynthesis. hupSL constitute a transcriptional unit, and are essentially transcribed under N(2)-fixing conditions. The bidirectional Hydrogenase consists of a Hydrogenase and a diaphorase part, and the corresponding five hox genes are not always clustered or cotranscribed. The biosynthesis/maturation of NiFe-Hydrogenases is highly complex, requiring several core proteins. In cyanobacteria, the genes that are thought to affect Hydrogenases pleiotropically (hyp), as well as the genes presumably encoding the Hydrogenase-specific endopeptidases (hupW and hoxW) have been identified and characterized. Furthermore, NtcA and LexA have been implicated in the transcriptional regulation of the uptake and the bidirectional enzyme respectively. Recently, the phylogenetic origin of cyanobacterial and algal Hydrogenases was analyzed, and it was proposed that the current distribution in cyanobacteria reflects a differential loss of genes according to their ecological needs or constraints. In addition, the possibilities and challenges of cyanobacterial-based H(2) production are addressed.
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genes involved in the maturation of Hydrogenase s in the nonheterocystous cyanobacterium lyngbya majuscula ccap 1446 4
International Journal of Hydrogen Energy, 2006Co-Authors: Elsa Leitão, Pedro Moradasferreira, Daniela Ferreira, Filipe Pinto, Sara Pereira, Joana Bondoso, Paula TamagniniAbstract:Abstract Lyngbya majuscula CCAP 1446/4 is a N 2 -fixing filamentous nonheterocystous cyanobacterium that possesses two NiFe Hydrogenases: an uptake and a bidirectional Hydrogenase. The biosynthesis/maturation of NiFe Hydrogenases is a highly complex process requiring several proteins. This work presents the characterization of the hyp cluster in L. majuscula . The hyp genes are located ca. 8 kb upstream from the uptake Hydrogenase structural genes, and seem to be transcribed as a single operon, including three other ORFs interspersed throughout the cluster. In addition, the transcriptional start point was identified 21 bp upstream of hypF , and regulatory sequences were recognized within the promoter region. Several ORFs could also be discerned between the hup and the hyp genes. Moreover, hupW , the gene encoding the putative uptake Hydrogenase C-terminal endopeptidase was found 1102 bp downstream of hupL . The Hydrogenases maturation process and its regulation are discussed for cyanobacteria possessing both or just one Hydrogenase.
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Genes involved in the maturation of Hydrogenase(s) in the nonheterocystous cyanobacterium Lyngbya majuscula CCAP 1446/4
International Journal of Hydrogen Energy, 2006Co-Authors: Elsa Leitão, Pedro Moradas-ferreira, Daniela Ferreira, Filipe Pinto, Sara Pereira, Joana Bondoso, Paula TamagniniAbstract:Abstract Lyngbya majuscula CCAP 1446/4 is a N 2 -fixing filamentous nonheterocystous cyanobacterium that possesses two NiFe Hydrogenases: an uptake and a bidirectional Hydrogenase. The biosynthesis/maturation of NiFe Hydrogenases is a highly complex process requiring several proteins. This work presents the characterization of the hyp cluster in L. majuscula . The hyp genes are located ca. 8 kb upstream from the uptake Hydrogenase structural genes, and seem to be transcribed as a single operon, including three other ORFs interspersed throughout the cluster. In addition, the transcriptional start point was identified 21 bp upstream of hypF , and regulatory sequences were recognized within the promoter region. Several ORFs could also be discerned between the hup and the hyp genes. Moreover, hupW , the gene encoding the putative uptake Hydrogenase C-terminal endopeptidase was found 1102 bp downstream of hupL . The Hydrogenases maturation process and its regulation are discussed for cyanobacteria possessing both or just one Hydrogenase.
