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Main Title: A membrane‐bound [NiFe]‐hydrogenase large subunit precursor whose C‐terminal extension is not essential for cofactor incorporation but guarantees optimal maturation
Author(s): Hartmann, Sven
Frielingsdorf, Stefan
Caserta, Giorgio
Lenz, Oliver
Type: Article
Abstract: [NiFe]‐hydrogenases catalyze the reversible conversion of molecular hydrogen into protons end electrons. This reaction takes place at a NiFe(CN)2(CO) cofactor located in the large subunit of the bipartite hydrogenase module. The corresponding apo‐protein carries usually a C‐terminal extension that is cleaved off by a specific endopeptidase as soon as the cofactor insertion has been accomplished by the maturation machinery. This process triggers complex formation with the small, electron‐transferring subunit of the hydrogenase module, revealing catalytically active enzyme. The role of the C‐terminal extension in cofactor insertion, however, remains elusive. We have addressed this problem by using genetic engineering to remove the entire C‐terminal extension from the apo‐form of the large subunit of the membrane‐bound [NiFe]‐hydrogenase (MBH) from Ralstonia eutropha. Unexpectedly, the MBH holoenzyme derived from this precleaved large subunit was targeted to the cytoplasmic membrane, conferred H2‐dependent growth of the host strain, and the purified protein showed exactly the same catalytic activity as native MBH. The only difference was a reduced hydrogenase content in the cytoplasmic membrane. These results suggest that in the case of the R. eutropha MBH, the C‐terminal extension is dispensable for cofactor insertion and seems to function only as a maturation facilitator.
Subject(s): chemolithotrophy
cofactor assembly
Tat transport
Issue Date: 16-Mar-2020
Date Available: 16-Dec-2020
Language Code: en
DDC Class: 541 Physikalische Chemie
Sponsor/Funder: DFG, 390540038, EXC 2008: Unifying Systems in Catalysis "UniSysCat"
TU Berlin, Open-Access-Mittel - 2020
Journal Title: MicrobiologyOpen
Publisher: Wiley
Volume: 9
Issue: 6
Publisher DOI: 10.1002/mbo3.1029
Page Start: 1197
Page End: 1206
EISSN: 2045-8827
TU Affiliation(s): Fak. 2 Mathematik und Naturwissenschaften » Inst. Chemie » FG Physikalische Chemie / Biophysikalische Chemie
Appears in Collections:Technische Universität Berlin » Publications

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