The roles of hydrogenases 3 and 4, and the F0F1‐ATPase, in H2 production by Escherichia coli at alkaline and acidic pH

FEBS Letters

Trchounian, Armen¹  Bagramyan, Karine¹  Mnatsakanyan, Nelli¹  Poladian, Anna¹  Vassilian, Anait² 

[1]Department of Biophysics of the Biological Faculty, Yerevan State University, 1 Alex Manougian Street, 375049 Yerevan, Armenia

[2]Department of Biochemistry of the Biological Faculty, Yerevan State University, 1 Alex Manougian Street, 375049 Yerevan, Armenia

关键词: Hydrogenase;    F0F1-ATPase;    H2 production;    Fermentation;    Escherichia coli;    F0F1;    the H+-translocating ATP synthase;    Fdh-H;    formate dehydrogenase H;    FHL;    formate hydrogenlyase;    Hyd-1;    Hyd-2;    Hyd-3 and Hyd-4;    hydrogenases 1;    2;    3 and 4;    respectively;    ND2;    ND4;    ND5;    denoted subunits of NADH dehydrogenase of NADH:ubiquinone oxidoreductase complex;    DCCD;    N;    N′-dicyclohexylcarbodiimide;    Δμ H +;    the transmembrane proton electrochemical gradient;   

DOI  :  10.1016/S0014-5793(02)02555-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The hyc operon of Escherichia coli encodes the H₂-evolving hydrogenase 3 (Hyd-3) complex that, in conjunction with formate dehydrogenase H (Fdh-H), constitutes a membrane-associated formate hydrogenlyase (FHL) catalyzing the disproportionation of formate to CO₂ and H₂ during fermentative growth at low pH. Recently, an operon (hyf) encoding a potential second H₂-evolving hydrogenase (Hyd-4) was identified in E. coli. In this study the roles of the hyc- and hyf-encoded systems in formate-dependent H₂ production and Fdh-H activity have been investigated. In cells grown on glucose under fermentative conditions at slightly acidic pH the production of H₂ was mostly Hyd-3- and Fdh-H-dependent, and Fdh-H activity was also mainly Hyd-3-dependent. However, at slightly alkaline pH, H₂ production was found to be largely Hyd-4, Fdh-H and F₀F₁-ATPase-dependent, and Fdh-H activity was partially dependent on Hyd-4 and F₀F₁-ATPase. These results suggest that, at slightly alkaline pH, H₂ production and Fdh-H activity are dependent on both the F₀F₁-ATPase and a novel FHL, designated FHL-2, which is composed of Hyd-4 and Fdh-H, and is driven by a proton gradient established by the F₀F₁-ATPase.

【 授权许可】

Unknown