Structure of unique proton-translocating enzymes from methanosarcina mazei GÖ1

• Applicant: Professor Dr. Uwe Deppenmeier
• Subject Area: Biochemistry
• Term: from 1999 to 2006
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5172342

It was shown that F420H₂-dependent 2-hydroxyphenazine reduction as catalyzed by the F420H₂-DH is coupled to proton translocation across the cytoplasmic membrane. In the sulfate reducing archaeon Archaeoglobus fulgidus a similar enzyme was identified and the corresponding genes were sequenced. These unique F420H₂-dependent proton pumps and the energy conserving NADH dehydrogenase from bacteria and eukarya are similar with respect to the complex composition, prosthetic groups and the chemical reactivity of electron donors and acceptors. By comparison of the deduced amino acid sequences it became evident that the membrane-intrinsic and the membrane-associated modules of NADH-DH have their counterparts in the F420H₂-DH. The electron input module seems to be different and is adjusted to the special electron donor. The research proposed in this application comprises the investigation of the operon structure of the F420H₂-DH, the complementation of nuo-mutants of E. coli and the overexpression of the F420H₂-oxidizing enzyme. Furthermore, the composition of the FeS-clusters and FAD will be elucidated. These experiments should contribute to a general understanding of the mechanism of H+-translocating dehydrogenases and the modular evolution with respect to the origin of the modules.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1070: Struktur funktioneller Module von energiewandelnden Systemen in Prokaryoten