title: Structural and functional characterization of the Mycobacterium tuberculosis uridine monophosphate kinase: insights into the allosteric regulation.
abstract: Nucleoside Monophosphate Kinases (NMPKs) family are key enzymes in nucleotide metabolism. Bacterial UMPKs depart from the main superfamily of NMPKs. Having no eukaryotic counterparts they represent attractive therapeutic targets. They are regulated by GTP and UTP, while showing different mechanisms in Gram(+), Gram(-) and archaeal bacteria. In this work, we have characterized the mycobacterial UMPK (UMPKmt) combining enzymatic and structural investigations with site-directed mutagenesis. UMPKmt exhibits cooperativity toward ATP and an allosteric regulation by GTP and UTP. The crystal structure of the complex of UMPKmt with GTP solved at 2.5 Å, was merely identical to the modelled apo-form, in agreement with SAXS experiments. Only a small stretch of residues was affected upon nucleotide binding, pointing out the role of macromolecular dynamics rather than major structural changes in the allosteric regulation of bacterial UMPKs. We further probe allosteric regulation by site-directed mutagenesis. In particular, a key residue involved in the allosteric regulation of this enzyme was identified.
authors.affiliation: Atelier de Bio- et Chimie Informatique Structurale, CNRS, UMR5048, Centre de Biochimie Structurale, 29 rue de Navacelles, F-34090 Montpellier, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Labesse
authors.forename: Khaled
authors.initials: K
authors.lastname: Benkali
authors.forename: Isabelle
authors.initials: I
authors.lastname: Salard-Arnaud
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Gilles
authors.forename: Hélène
authors.initials: H
authors.lastname: Munier-Lehmann
mesh_terms: D000494:Allosteric Regulation; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009169:Mycobacterium tuberculosis / Q000201:enzymology*; D009703:Nucleoside-Phosphate Kinase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; C023276:uridine monophosphate kinase; D009703:Nucleoside-Phosphate Kinase