title: Structure of α-carbonic anhydrase from the human pathogen Helicobacter pylori.
abstract: The crystal structure of α-carbonic anhydrase, an enzyme present in the periplasm of Helicobacter pylori, a bacterium that affects humans and that is responsible for several gastric pathologies, is described. Two enzyme monomers are present in the asymmetric unit of the monoclinic space group P21, forming a dimer in the crystal. Despite the similarity of the enzyme structure to those of orthologues from other species, the H. pylori protein has adopted peculiar features in order to allow the bacterium to survive in the difficult environment of the human stomach. In particular, the crystal structure shows how the bacterium has corrected for the mutation of an essential amino acid important for catalysis using a negative ion from the medium and how it localizes close to the inner membrane in the periplasm. Since carbonic anhydrase is essential for the bacterial colonization of the host, it is a potential target for antibiotic drugs. The definition of the shape of the active-site entrance and cavity constitutes a basis for the design of specific inhibitors.
authors.affiliation: Department of Biomedical Sciences, University of Padua, Via Ugo Bassi 58/B, 35131 Padua, Italy.
authors.forename: Maria Elena
authors.initials: ME
authors.lastname: Compostella
authors.affiliation: Department of Biomedical Sciences, University of Padua, Via Ugo Bassi 58/B, 35131 Padua, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Berto
authors.affiliation: Department of Biomedical Sciences, University of Padua, Via Ugo Bassi 58/B, 35131 Padua, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Vallese
authors.affiliation: Department of Biomedical Sciences, University of Padua, Via Ugo Bassi 58/B, 35131 Padua, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Zanotti
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D002256:Carbonic Anhydrases / Q000737:chemistry* / Q000235:genetics; D003001:Cloning, Molecular; D003460:Crystallization; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D016480:Helicobacter pylori / Q000737:chemistry* / Q000201:enzymology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019897:Periplasm / Q000737:chemistry; D011485:Protein Binding; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry* / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000737:chemistry* / Q000235:genetics; D016415:Sequence Alignment; D040681:Structural Homology, Protein
chemical_list: D001426:Bacterial Proteins; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; D002256:Carbonic Anhydrases
keywords: Helicobacter pylori; carbonic anhydrase; metalloproteins; periplasmic protein