title: Structure and function of Rv0130, a conserved hypothetical protein from Mycobacterium tuberculosis.
abstract: A large fraction of the Mycobacterium tuberculosis genome codes for proteins of unknown function. We here report the structure of one of these proteins, Rv0130, solved to a resolution of 1.8 å. The Rv0130 monomer features a single hotdog fold composed of a highly curved beta-sheet on top of a long and a short alpha-helix. Two monomers in turn pack to form a double-hotdog-folded homodimer, similar to a large group of enzymes that use thiol esters as substrates. Rv0130 was found to contain a highly conserved R-specific hydratase motif buried deeply between the two monomers. Our biochemical studies show that the protein is able to hydrate a short trans-2-enoyl-coenzyme A moiety with a k(cat) of 1.1 x 10(2) sec(-1). The importance of the side chains of D40 and H45 for hydratase activity is demonstrated by site-directed mutagenesis. In contrast to many hotdog-folded proteins, a proline residue distorts the central helix of Rv0130. This distortion allows the creation of a long, curved tunnel, similar to the substrate-binding channels of long-chain eukaryotic hydratase 2 enzymes.
authors.affiliation: Department of Cell and Molecular Biology, Uppsala University, Biomedical Center, SE-751 24 Uppsala, Sweden.
authors.forename: Patrik
authors.initials: P
authors.lastname: Johansson
authors.forename: Alina
authors.initials: A
authors.lastname: Castell
authors.forename: T Alwyn
authors.initials: TA
authors.lastname: Jones
authors.forename: Kristina
authors.initials: K
authors.lastname: Bäckbro
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D006836:Hydro-Lyases / Q000737:chemistry; D007700:Kinetics; D015394:Molecular Structure; D016297:Mutagenesis, Site-Directed; D009169:Mycobacterium tuberculosis / Q000201:enzymology*; D011487:Protein Conformation
chemical_list: D001426:Bacterial Proteins; D006836:Hydro-Lyases