The sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough possesses four periplasmic hydrogenases to facilitate the oxidation of molecular hydrogen. These include an [Fe] hydrogenase, an [NiFeSe] hydrogenase, and two [NiFe] hydrogenases encoded by the hyd, hys, hyn1, and hyn2 genes, respectively. In order to understand their cellular functions, we have compared the growth rates of exi...

Soybean plants and Rhizobium japonicum 122 DES, a hydrogen uptake-positive strain, were cultured in media purified to remove Ni. Supplemental Ni had no significant effect on the dry matter or total N content of plants. However, the addition of Ni to both nitrate-grown and symbiotically grown plants resulted in a 7- to 10-fold increase in urease activity (urea amidohydrolase, EC 3.5.1.5) in leav...

The aerobic nitrogen-fixing hydrogen bacterium Xanthobacter autotrophicus strain GZ29 [1] can grow autotrophically with hydrogen, oxygen, carbon dioxide, and molecular nitrogen as sole sources of electrons, energy, carbon, and nitrogen. Carbon dioxide is fixed via the Calvin cycle, and for activation of hydrogen only a membrane-bound hydrogenase activity was detected which does not reduce NAD [...

Two distinct processes are involved in the formation of active hydrogenase during anaerobic adaptation of Chlamydomonas reinhardtii cells. In the first 30 minutes of anaerobiosis, nearly all of the hydrogenase activity can be attributed to activation of a constituitive polypeptide precursor, based on the insensitivity of the process to treatment with cycloheximide (15 micrograms per milliliter)...

H2 metabolism is proposed to be the most ancient and diverse mechanism of energy-conservation. The metalloenzymes mediating this metabolism, hydrogenases, are encoded by over 60 microbial phyla and are present in all major ecosystems. We developed a classification system and web tool, HydDB, for the structural and functional analysis of these enzymes. We show that hydrogenase function can be pr...

The reversible hydrogenase of the cyanobacterium Anacystis nidulans was purified 250-fold by classical methods. Activity staining on gels obtained by native PAG E allowed to identify two bands. Antibodies were raised against the electrophoretically hom ogeneous protein. The m olecu­ lar weight of the hydrogenase was determined by SD S-PAG E followed by Western blot analysis with these antibodie...

BACKGROUND The realization of hydrogenase-based technologies for renewable H(2) production is presently limited by the need for scalable and high-yielding methods to supply active hydrogenases and their required maturases. PRINCIPAL FINDINGS In this report, we describe an improved Escherichia coli-based expression system capable of producing 8-30 mg of purified, active [FeFe] hydrogenase per ...

The [NiFe] centers at the active sites of the Escherichia coli hydrogenase enzymes are assembled by a team of accessory proteins that includes the products of the hyp genes. To determine whether any other proteins are involved in this process, the sequential peptide affinity system was used. The analysis of the proteins in a complex with HypB revealed the peptidyl-prolyl cis/trans-isomerase Sly...

MATERIALS AND METHODS UPADHYAY, J. (Washington State University, Pullman) AND J. L. STOKES. Temperature-sensitive hydrogenase and hydrogenase synthesis in a psychrophilic bacterium. J. Bacteriol. 86:992998. 1963.-Hydrogenase and its synthesis were more heat-sensitive in psychrophilic strain 82 than in mesophilic Escherichia coli. The enzyme -as not formed above 20 C by the psychrophile, whereas...

Maturation of [NiFe]-hydrogenase requires the insertion of iron, cyanide and carbon monoxide, followed by nickel, to the catalytic core of the enzyme. Hydrogenase maturation factor HypB is a metal-binding GTPase that is essential for the nickel delivery to the hydrogenase. Here we report the crystal structure of Archeoglobus fulgidus HypB (AfHypB) in apo-form. We showed that AfHypB recognizes g...