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

FEBS Lett. 2002 Apr 10;516(1-3):172-8. doi: 10.1016/s0014-5793(02)02555-3.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Escherichia coli / enzymology*
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Formate Dehydrogenases / genetics
  • Formate Dehydrogenases / metabolism*
  • Genes, Bacterial
  • Hydrogen / metabolism
  • Hydrogen-Ion Concentration
  • Hydrogenase / genetics
  • Hydrogenase / metabolism*
  • Multienzyme Complexes / genetics
  • Multienzyme Complexes / metabolism*
  • Mutation
  • Proton-Translocating ATPases / genetics
  • Proton-Translocating ATPases / metabolism*
  • Protoplasts / metabolism

Substances

  • Multienzyme Complexes
  • Hydrogen
  • Hydrogenase
  • Formate Dehydrogenases
  • formate hydrogenlyase
  • Proton-Translocating ATPases