2e2e | pdb_00002e2e
TPR domain of NrfG mediates the complex formation between heme lyase and formate-dependent nitrite reductase in Escherichia Coli O157:H7
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Overview
Escherichia coli synthesize C-type cytochromes only during anaerobic, growth in media supplemented with nitrate and nitrite. The reduction of, nitrate to ammonium in the periplasm of Escherichia coli involves two, separate periplasmic enzymes, nitrate reductase and nitrite reductase. The, nitrite reductase involved, NrfA, contains cytochrome C and is synthesized, coordinately with a membrane-associated cytochrome C, NrfB, during growth, in the presence of nitrite or in limiting nitrate concentrations. The, genes NrfE, NrfF, and NrfG are required for the formate-dependent nitrite, reduction pathway, which involves at least two C-type cytochrome proteins, NrfA and NrfB. The NrfE, NrfF, and NrfG genes (heme lyase complex) are, involved in the maturation of a special C-type cytochrome, apocytochrome C, (apoNrfA), to cytochrome C (NrfA) by transferring a heme to the unusual, heme binding motif of the Cys-Trp-Ser-Cys-Lys sequence in apoNrfA protein., Thus, in order to further investigate the roles of NrfG in the formation, of heme lyase complex (NrfEFG) and in the interaction between heme lyase, complex and formate-dependent nitrite reductase (NrfA), we determined the, crystal structure of NrfG at 2.05 A. The structure of NrfG showed that the, contact between heme lyase complex (NrfEFG) and NrfA is accomplished via a, TPR domain in NrfG which serves as a binding site for the C-terminal motif, of NrfA. The portion of NrfA that binds to TPR domain of NrfG has a unique, secondary motif, a helix followed by about a six-residue C-terminal loop, (the so called "hook conformation"). This study allows us to better, understand the mechanism of special C-type cytochrome assembly during the, maturation of formate-dependent nitrite reductase, and also adds a new TPR, binding conformation to the list of TPR-mediated protein-protein, interactions. Proteins 2007. (c) 2007 Wiley-Liss, Inc.
About this Structure
2E2E is a Single protein structure of sequence from Escherichia coli with BME and IMD as ligands. Full crystallographic information is available from OCA.
Reference
TPR domain of NrfG mediates complex formation between heme lyase and formate-dependent nitrite reductase in Escherichia coli O157:H7., Han D, Kim K, Oh J, Park J, Kim Y, Proteins. 2007 Sep 5;. PMID:17803240
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