Open AccessThe N‐terminal domains of the paralogous HycE and Nuo CD govern assembly of the respective formate hydrogenlyase and NADH dehydrogenase complexes
Author(s) -
Skorupa Philipp,
Lindenstrauß Ute,
Burschel Sabrina,
Blumenscheit Christian,
Friedrich Thorsten,
Pinske Constanze
Publication year - 2020
Publication title -
febs open bio
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.718
H-Index - 31
ISSN - 2211-5463
DOI - 10.1002/2211-5463.12787
Subject(s) - cofactor , formate , protein subunit , hydrogenase , escherichia coli , formate dehydrogenase , biochemistry , fusion protein , chemistry , stereochemistry , enzyme , biology , catalysis , recombinant dna , gene
Formate hydrogenlyase ( FHL ) is the main hydrogen‐producing enzyme complex in enterobacteria. It converts formate to CO 2 and H 2 via a formate dehydrogenase and a [NiFe]‐hydrogenase. FHL and complex I are evolutionarily related and share a common core architecture. However, complex I catalyses the fundamentally different electron transfer from NADH to quinone and pumps protons. The catalytic FHL subunit, HycE, resembles Nuo CD of Escherichia coli complex I; a fusion of NuoC and NuoD present in other organisms. The C‐terminal domain of HycE harbours the [NiFe]‐active site and is similar to other hydrogenases, while this domain in Nuo CD is involved in quinone binding. The N‐terminal domains of these proteins do not bind cofactors and are not involved in electron transfer. As these N‐terminal domains are separate proteins in some organisms, we removed them in E. coli and observed that both FHL and complex I activities were essentially absent. This was due to either a disturbed assembly or to complex instability. Replacing the N‐terminal domain of HycE with a 180 amino acid E. coli NuoC protein fusion did not restore activity, indicating that the domains have complex‐specific functions. A FHL complex in which the N‐ and C‐terminal domains of HycE were physically separated still retained most of its FHL activity, while the separation of Nuo CD abolished complex I activity completely. Only the FHL complex tolerates physical separation of the HycE domains. Together, the findings strongly suggest that the N‐terminal domains of these proteins are key determinants in complex assembly.