Programmed DNA Rearrangement of A Hydrogenase Gene During Anabaena Heterocyst Development

Carrasco, Claudio D.; Garcia, Joleen S.; Golden, James W.

doi:10.1007/978-0-585-35132-2_27

Cited by 5 publications

(3 citation statements)

References 21 publications

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“…This explains the importance of hup ) mutants, which have been studied in more detail. It could be shown that due to the deletion of a part of the hupSL genes or the xisC gene the mutants produced (and evolved) molecular hydrogen when grown in air (Carrasco et al 1998;Happe et al 2000;Lindberg et al 2002;Lindblad et al 2002). However, with the construction of a hup ) /hox ) double mutant in Anabaena sp.…”

Section: Discussionmentioning

confidence: 96%

Cyanobacterial H2 production ? a comparative analysis

Schütz

Happe

Troshina

et al. 2004

Planta

178

108

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Several unicellular and filamentous, nitrogen-fixing and non-nitrogen-fixing cyanobacterial strains have been investigated on the molecular and the physiological level in order to find the most efficient organisms for photobiological hydrogen production. These strains were screened for the presence or absence of hup and hox genes, and it was shown that they have different sets of genes involved in H(2) evolution. The uptake hydrogenase was identified in all N(2)-fixing cyanobacteria, and some of these strains also contained the bidirectional hydrogenase, whereas the non-nitrogen fixing strains only possessed the bidirectional enzyme. In N(2)-fixing strains, hydrogen was mainly produced by the nitrogenase as a by-product during the reduction of atmospheric nitrogen to ammonia. Therefore, hydrogen production was investigated both under non-nitrogen-fixing conditions and under nitrogen limitation. It was shown that the hydrogen uptake activity is linked to the nitrogenase activity, whereas the hydrogen evolution activity of the bidirectional hydrogenase is not dependent or even related to diazotrophic growth conditions. With regard to large-scale hydrogen evolution by N(2)-fixing cyanobacteria, hydrogen uptake-deficient mutants have to be used because of their inability to re-oxidize the hydrogen produced by the nitrogenase. On the other hand, fermentative H(2) production by the bidirectional hydrogenase should also be taken into account in further investigations of biological hydrogen production.

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Section: Discussionmentioning

confidence: 96%

Cyanobacterial H2 production ? a comparative analysis

Schütz

Happe

Troshina

et al. 2004

Planta

178

108

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“…3). The hupL element contains, in one of its borders, the gene that encodes the recombinase necessary for the excision -xisC (Carrasco et al, 1995(Carrasco et al, , 1998(Carrasco et al, , 2005. Site-directed mutagenesis revealed that the XisC protein has a functional similarity to the phage integrase family of recombinases.…”

Section: Hupl Rearrangement In Heterocystous Strainsmentioning

confidence: 99%

Cyanobacterial hydrogenases: diversity, regulation and applications

et al. 2007

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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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“…Uptake hydrogenases, which have been found in all nitrogen-fixing cyanobacteria, function to catalyze the consumption of the molecular hydrogen produced as a by-product of nitrogen fixation (39). The predicted XisC amino acid sequence shows strong similarity to cyanobacterial XisA recombinases as well as weak similarity to the phage integrase family of phage site-specific recombinases (6,34). The phage integrase family contains a large number of genes found widely distributed in many different microorganisms (34).…”

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confidence: 99%

Heterocyst-Specific Excision of the Anabaena sp. Strain PCC 7120 hupL Element Requires xisC

et al. 2005

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In nitrogen-limiting conditions, approximately 10% of the vegetative cells in filaments of the cyanobacterium Anabaena (Nostoc) sp. strain PCC 7120 differentiate into nitrogen-fixing heterocysts. During the late stages of heterocyst differentiation, three DNA elements, each embedded within an open reading frame, are programmed to excise from the chromosome by site-specific recombination. The DNA elements are named after the genes that they interrupt: nifD, fdxN, and hupL. The nifD and fdxN elements each contain a gene, xisA or xisF, respectively, that encodes the site-specific recombinase required for programmed excision of the element. Here, we show that the xisC gene (alr0677), which is present at one end of the 9,435-bp hupL element, is required for excision of the hupL element. A strain in which the xisC gene was inactivated showed no detectable excision of the hupL element. hupL encodes the large subunit of uptake hydrogenase. The xisC mutant forms heterocysts and grows diazotrophically, but unlike the wild type, it evolved hydrogen gas under nitrogen-fixing conditions. Overexpression of xisC from a plasmid in a wild-type background caused a low level of hupL rearrangement even in nitrogen-replete conditions. Expression of xisC in Escherichia coli was sufficient to produce rearrangement of an artificial substrate plasmid bearing the hupL element recombination sites. Sequence analysis indicated that XisC is a divergent member of the phage integrase family of recombinases. Site-directed mutagenesis of xisC showed that the XisC recombinase has functional similarity to the phage integrase family.

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Programmed DNA Rearrangement of A Hydrogenase Gene During Anabaena Heterocyst Development

Cited by 5 publications

References 21 publications

Cyanobacterial H2 production ? a comparative analysis

Cyanobacterial H2 production ? a comparative analysis

Cyanobacterial hydrogenases: diversity, regulation and applications

Heterocyst-Specific Excision of the Anabaena sp. Strain PCC 7120 hupL Element Requires xisC

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