[FeFe]-Hydrogenase Abundance and Diversity along a Vertical Redox Gradient in Great Salt Lake, USA

International Journal of Molecular Sciences

Eric S. Boyd³  Trinity L. Hamilton⁴  Kevin D. Swanson⁴  Alta E. Howells⁴  Bonnie K. Baxter²  Jonathan E. Meuser¹  Matthew C. Posewitz¹  John W. Peters⁴ 

[1] Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401, USA; E-Mails:;Department of Biology and the Great Salt Lake Institute, Westminster College, Salt Lake City, UT 84105, USA; E-Mail:;Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA; E-Mail:;Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA; E-Mails:

关键词: [FeFe]-hydrogenase;    electron bifurcation;    hydrogen;    photosynthesis;    fermentation;    oxygen tolerance;    hydropathy;    hypersaline;   

DOI  :  10.3390/ijms151221947

来源: mdpi

【 摘 要 】

The use of [FeFe]-hydrogenase enzymes for the biotechnological production of H₂ or other reduced products has been limited by their sensitivity to oxygen (O₂). Here, we apply a PCR-directed approach to determine the distribution, abundance, and diversity of hydA gene fragments along co-varying salinity and O₂ gradients in a vertical water column of Great Salt Lake (GSL), UT. The distribution of hydA was constrained to water column transects that had high salt and relatively low O₂ concentrations. Recovered HydA deduced amino acid sequences were enriched in hydrophilic amino acids relative to HydA from less saline environments. In addition, they harbored interesting variations in the amino acid environment of the complex H-cluster metalloenzyme active site and putative gas transfer channels that may be important for both H₂ transfer and O₂ susceptibility. A phylogenetic framework was created to infer the accessory cluster composition and quaternary structure of recovered HydA protein sequences based on phylogenetic relationships and the gene contexts of known complete HydA sequences. Numerous recovered HydA are predicted to harbor multiple N- and C-terminal accessory iron-sulfur cluster binding domains and are likely to exist as multisubunit complexes. This study indicates an important role for [FeFe]-hydrogenases in the functioning of the GSL ecosystem and provides new target genes and variants for use in identifying O₂ tolerant enzymes for biotechnological applications.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.