This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Sayavedra-Soto, L A Articles by Arp, D J Search for Related Content PubMed PubMed Citation Articles by Sayavedra-Soto, L A Articles by Arp, D J

research-article

In Azotobacter vinelandii hydrogenase, substitution of serine for the cysteine residues at positions 62, 65, 294, and 297 in the small (HoxK) subunit affects H2 oxidation [corrected]

Laboratory for Nitrogen Fixation, Oregon State University, Corvallis 97331-2902.

ABSTRACT

The essential role of the small (HoxK) subunit of hydrogenase of Azotobacter vinelandii in H2 oxidation was established. This was achieved by modification of the two Cys-X2-Cys amino acid motifs at the N and C termini of the HoxK subunit (Cys-62, -65, -294, and -297). The Cys codons were individually mutated to Ser codons. Modifications in these two motifs resulted in loss of hydrogenase activity. At the N terminus, the mutations of the codons for the motif Cys-62-Thr-Cys-64-Cys-65 decreased the activity of hydrogenase to levels no higher than 30% of those of the parental strain. H2 oxidation with the alternate electron acceptors methylene blue and benzyl viologen was decreased. H2 evolution and exchange activities were also affected. Cys-64 possibly substitutes for either Cys-62 or Cys-65, allowing for partial activity. Mutation of the codons for Cys-294 and Cys-297 to Ser codons resulted in no hydrogenase activity. The results are consistent with alterations of the ligands of FeS clusters in the HoxK subunit of hydrogenase [corrected].

This article has been cited by other articles:

• Coppi, M. V. (2005). The hydrogenases of Geobacter sulfurreducens: a comparative genomic perspective. Microbiology 151: 1239-1254 [Abstract] [Full Text]  
• Meek, L., Arp, D. J. (2000). The Hydrogenase Cytochrome b Heme Ligands of Azotobacter vinelandii Are Required for Full H2 Oxidation Capability. J. Bacteriol. 182: 3429-3436 [Abstract] [Full Text]  
• Massanz, C., Schmidt, S., Friedrich, B. (1998). Subforms and In Vitro Reconstitution of the NAD-Reducing Hydrogenase of Alcaligenes eutrophus. J. Bacteriol. 180: 1023-1029 [Abstract] [Full Text]