Expression and mutagenesis of the NqrC subunit of the NQR respiratory Na(+) pump from Vibrio cholerae with covalently attached FMN.

TitleExpression and mutagenesis of the NqrC subunit of the NQR respiratory Na(+) pump from Vibrio cholerae with covalently attached FMN.
Publication TypeJournal Article
Year of Publication2001
AuthorsBarquera B, Häse CC, Gennis RB
JournalFEBS letters
Volume492
Issue1-2
Pagination45-9
Date Published2001 Mar 9
ISSN0014-5793
KeywordsAmino Acid Sequence, Bacterial Proteins, Flavin Mononucleotide, Gene Expression, Histidine, Molecular Sequence Data, Mutagenesis, Site-Directed, Quinone Reductases, Threonine, Vibrio cholerae
Abstract

The Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR) is present in the membranes of a number of marine bacteria and pathogenic bacteria. Two of the six subunits of the Na(+)-NQR, NqrB and NqrC, have been previously shown to contain covalently bound flavin adenine mononucleotide (FMN). In the current work, the cloning of nqrC from Vibrio cholerae is reported. The gene has been expressed in V. cholerae and shown to contain one equivalent of covalently bound FMN. In contrast, no covalent flavin was detected when threonine-225 was replaced by leucine. The data show that the FMN attachment does not require assembly of the enzyme and are consistent with the unusual threonine attachment site.

Alternate JournalFEBS Lett.