title: Helicobacter pylori expresses an autolytic enzyme: gene identification, cloning, and theoretical protein structure.
abstract: Helicobacter pylori is an important pathogen of the gastric system. The clinical outcome of infection is thought to be correlated with some genetic features of the bacterium. However, due to the extreme genetic variability of this organism, it is hard to draw definitive conclusions concerning its virulence factors. Here we describe a novel H. pylori gene which expresses an autolytic enzyme that is also capable of degrading the cell walls of both gram-positive and gram-negative bacteria. We designated this gene lys. We found this gene and observed its expression in a number of unrelated clinical strains, a fact that suggests that it is well conserved in the species. A comparison of the nucleotide sequences of lys and the hypothetical gene HP0339 from H. pylori strain ATCC 26695 revealed almost total identity, except for the presence of an insertion consisting of 24 nucleotides in the lys sequence. The coding sequences of lys and HP0339 show a high degree of homology with the coding sequence of bacteriophage T4 lysozyme. Because of this similarity, it was possible to model the three-dimensional structures of both the lys and HP0339 products.
authors.affiliation: Dipartimento di Biochimica, Biofisica e Chimica delle Macromolecole, Università degli Studi di Trieste, Italy.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Marsich
authors.forename: Pierfrancesco
authors.initials: P
authors.lastname: Zuccato
authors.forename: Sonia
authors.initials: S
authors.lastname: Rizzi
authors.forename: Amedeo
authors.initials: A
authors.lastname: Vetere
authors.forename: Enrico
authors.initials: E
authors.lastname: Tonin
authors.forename: Sergio
authors.initials: S
authors.lastname: Paoletti
mesh_terms: D000595:Amino Acid Sequence; D001419:Bacteria / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001433:Bacteriolysis; D017122:Bacteriophage T4 / Q000201:enzymology; D002473:Cell Wall / Q000378:metabolism; D003001:Cloning, Molecular; D016481:Helicobacter Infections / Q000382:microbiology; D016480:Helicobacter pylori / Q000201:enzymology* / Q000235:genetics*; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009113:Muramidase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D009113:Muramidase