title: Hydrogenases in green algae: do they save the algae's life and solve our energy problems?
abstract: Green algae are the only known eukaryotes with both oxygenic photosynthesis and a hydrogen metabolism. Recent physiological and genetic discoveries indicate a close connection between these metabolic pathways. The anaerobically inducible hydA genes of algae encode a special type of highly active [Fe]-hydrogenase. Electrons from reducing equivalents generated during fermentation enter the photosynthetic electron transport chain via the plastoquinone pool. They are transferred to the hydrogenase by photosystem I and ferredoxin. Thus, the [Fe]-hydrogenase is an electron 'valve' that enables the algae to survive under anaerobic conditions. During sulfur deprivation, illuminated algal cultures evolve large quantities of hydrogen gas, and this promises to be an alternative future energy source.
authors.affiliation: Botanisches Institut, Abt. Molekulare Biochemie, Universität Bonn, Karlrobert-Kreiten-Strasse 13, 53115 Bonn, Germany. t.happe@uni-bonn.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Happe
authors.forename: Anja
authors.initials: A
authors.lastname: Hemschemeier
authors.forename: Martin
authors.initials: M
authors.lastname: Winkler
authors.forename: Annette
authors.initials: A
authors.lastname: Kaminski
mesh_terms: D000332:Aerobiosis; D000595:Amino Acid Sequence; D000693:Anaerobiosis; D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism; D016825:Chlamydomonas reinhardtii / Q000201:enzymology / Q000235:genetics; D000460:Chlorophyta / Q000201:enzymology* / Q000235:genetics; D005561:Formates / Q000378:metabolism; D006801:Humans; D006859:Hydrogen / Q000378:metabolism; D006864:Hydrogenase / Q000235:genetics* / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000235:genetics* / Q000378:metabolism; D008027:Light; D008969:Molecular Sequence Data; D010788:Photosynthesis / Q000502:physiology; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism; D045331:Photosystem I Protein Complex; D010944:Plants / Q000201:enzymology / Q000235:genetics; D017386:Sequence Homology, Amino Acid
chemical_list: D005561:Formates; D007506:Iron-Sulfur Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; C030544:formic acid; D002245:Carbon Dioxide; D006859:Hydrogen; C118830:iron hydrogenase; D006864:Hydrogenase