title: Characterization of peptidoglycan hydrolase in Cag pathogenicity island of Helicobacter pylori.
abstract: The Cag Type IV secretion apparatus proteins in Helicobacter pylori can mediate the injection of effector CagA protein into eukaryotic target cells. Although this apparatus forms an important pathway for bacterium-host interaction, its assembly process in vivo is poorly understood, and the proteins which contribute to break the bacterial cell walls in Cag-PAI have not yet been identified. The cagγ gene in Cag-PAI is a unique member that contains a conserved SLT catalysis domain, which makes it an attracting question whether cagy gene has the capacity to digest the bacterial cell wall. In the current study, therefore, the cagγ gene was cloned from the H. pylori NCTC 11637 and expressed in Escherichia coli, and its lytic effect on cell walls in vitro was observed. Results indicated that Cagγ protein has a lytic activity against bacterial cell walls. An allelic-exchange mutant (Δcagγ) was further constructed to investigate the relationship between Cagγ and effector CagA translocation. These results suggested that Cagγ contributed to the assembly of Cag Type IV secretion apparatus by digesting the peptidoglycan meshwork of bacterial cell walls.
authors.affiliation: Department of Microbiology, School of Medical Science and Laboratory Medicine, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu, 212013, China.
authors.forename: Qiao
authors.initials: Q
authors.lastname: Zhong
authors.forename: Shihe
authors.initials: S
authors.lastname: Shao
authors.forename: Runhong
authors.initials: R
authors.lastname: Mu
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
authors.forename: Shiteng
authors.initials: S
authors.lastname: Huang
authors.forename: Jun
authors.initials: J
authors.lastname: Han
authors.forename: He
authors.initials: H
authors.lastname: Huang
authors.forename: Shuwei
authors.initials: S
authors.lastname: Tian
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D001433:Bacteriolysis; D015153:Blotting, Western; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D005798:Genes, Bacterial / Q000235:genetics; D044404:Genomic Islands / Q000235:genetics*; D016480:Helicobacter pylori / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity*; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000235:genetics*; D010802:Phylogeny; D021381:Protein Transport; D011994:Recombinant Proteins / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D009238:N-Acetylmuramoyl-L-alanine Amidase