title: The crystal structure of Rv0813c from Mycobacterium tuberculosis reveals a new family of fatty acid-binding protein-like proteins in bacteria.
abstract: The gene Rv0813c from Mycobacterium tuberculosis, which codes for a hypothetical protein of unknown function, is conserved within the order Actinomycetales but absent elsewhere. The crystal structure of Rv0813c reveals a new family of proteins that resemble the fatty acid-binding proteins (FABPs) found in eukaryotes. Rv0813c adopts the 10-stranded beta-barrel fold typical of FABPs but lacks the double-helix insert that covers the entry to the binding site in the eukaryotic proteins. The barrel encloses a deep cavity, at the bottom of which a small cyclic ligand was found to bind to the hydroxyl group of Tyr192. This residue is part of a conserved Arg-X-Tyr motif much like the triad that binds the carboxylate group of fatty acids in FABPs. Most of the residues forming the internal surface of the cavity are conserved in homologous protein sequences found in CG-rich prokaryotes, strongly suggesting that Rv0813c is a member of a new family of bacterial FABP-like proteins that may have roles in the recognition, transport, and/or storage of small molecules in the bacterial cytosol.
authors.affiliation: Unité de Biochimie Structurale, CNRS URA 2185, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris, France.
authors.forename: William
authors.initials: W
authors.lastname: Shepard
authors.forename: Ahmed
authors.initials: A
authors.lastname: Haouz
authors.forename: Martin
authors.initials: M
authors.lastname: Graña
authors.forename: Alejandro
authors.initials: A
authors.lastname: Buschiazzo
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Betton
authors.forename: Stewart T
authors.initials: ST
authors.lastname: Cole
authors.forename: Pedro M
authors.initials: PM
authors.lastname: Alzari
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D001483:Base Sequence; D001665:Binding Sites; D003461:Crystallography; D019281:Dimerization; D050556:Fatty Acid-Binding Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D050556:Fatty Acid-Binding Proteins