1xoc
From Proteopedia
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The structure of the oligopeptide-binding protein, AppA, from Bacillus subtilis in complex with a nonapeptide.
Overview
Besides their role as a source of amino acids for Bacillus subtilis, exogenous peptides play important roles in the signalling pathways leading, to the development of competence and sporulation. B.subtilis has three, peptide transport systems all belonging to the ATP-binding cassette, family, a dipeptide permease (Dpp) and two oligopeptide permeases (Opp and, App) with overlapping specificity. These comprise a membrane-spanning, channel through which the peptide passes, a pair of ATPases which couple, ATP hydrolysis to peptide translocation and a lipid-modified, membrane-anchored extracellular "binding-protein" that serves as the, receptor for the system. Here, we present the crystal structure of a, soluble form of the peptide-binding protein AppA, which has been solved to, 1.6 A spacing by anomalous scattering and molecular replacement methods., The structure reveals a protein made of two distinct lobes with a topology, similar to those of DppA from Escherichia coli and OppA from Salmonella, typhimurium. Examination of the interlobe region reveals an enlarged, pocket, containing electron density defining a nonapeptide ligand. The, main-chain of the peptide is well defined and makes a series of polar, contacts with the protein including salt-bridges at both its termini. The, side-chain density is ambiguous in places, consistent with the, interpretation that a population of peptides is bound, whose average, electron density resembles the amino acid sequence N-VDSKNTSSW-C.
About this Structure
1XOC is a Single protein structure of sequence from Bacillus subtilis with ZN as ligand. Full crystallographic information is available from OCA.
Reference
The structure of the oligopeptide-binding protein, AppA, from Bacillus subtilis in complex with a nonapeptide., Levdikov VM, Blagova EV, Brannigan JA, Wright L, Vagin AA, Wilkinson AJ, J Mol Biol. 2005 Jan 28;345(4):879-92. PMID:15588833
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