title: Helicobacter hepaticus catalase shares surface-predicted epitopes with mammalian catalases.
abstract: Helicobacter hepaticus colonizes the murine intestine and has been associated with hepatic inflammation and neoplasia in susceptible mouse strains. In this study, the catalase of an enterohepatic Helicobacter was characterized for the first time. H. hepaticus catalase is a highly conserved enzyme that may be important for bacterial survival in the mammalian intestine. Recombinant H. hepaticus catalase was expressed in Escherichia coli in order to verify its enzymic activity in vitro. H. hepaticus catalase comprises 478 amino acids with a highly conserved haem-ligand domain. Three conserved motifs (R-F-Y-D, RERIPER and VVHAKG) in the haem-ligand domain and three surface-predicted motifs were identified in H. hepaticus catalase and are shared among bacterial and mammalian catalases. H. hepaticus catalase is present in the cytoplasmic and periplasmic compartments. Mice infected with H. hepaticus demonstrated immune responses to murine and H. hepaticus catalase, suggesting that Helicobacter catalase contains conserved structural motifs and may contribute to autoimmune responses. Antibodies to H. hepaticus catalase recognized murine hepatocyte catalase in hepatic tissue from infected mice. Antibodies from sera of H. hepaticus-infected mice reacted with peptides comprising two conserved surface-predicted motifs in H. hepaticus catalase. Catalases are highly conserved enzymes in bacteria and mammals that may contribute to autoimmune responses in animals infected with catalase-producing pathogens.
authors: Department of Pathology, Texas Children's Hospital, Houston, TX 77030, USA.|Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 01225, USA.
authors: Essam J
authors: EJ
authors: Alyamani
authors: MWG Biotech AG, Ebersberg, Germany.
authors: Petra
authors: P
authors: Brandt
authors: Department of Pathology, Texas Children's Hospital, Houston, TX 77030, USA.
authors: Jeremy A
authors: JA
authors: Pena
authors: Department of Pathology, Texas Children's Hospital, Houston, TX 77030, USA.
authors: Angela M
authors: AM
authors: Major
authors: Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors: James G
authors: JG
authors: Fox
authors: Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany.
authors: Sebastian
authors: S
authors: Suerbaum
authors: Department of Pathology, Texas Children's Hospital, Houston, TX 77030, USA.|Departments of Pathology, Molecular Virology & Microbiology, and Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
authors: James
authors: J
authors: Versalovic
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D015551:Autoimmunity; D002374:Catalase / Q000032:analysis / Q000737:chemistry / Q000276:immunology*; D017124:Conserved Sequence; D003429:Cross Reactions; D003593:Cytoplasm / Q000737:chemistry; D016481:Helicobacter Infections / Q000276:immunology*; D044923:Helicobacter hepaticus / Q000201:enzymology*; D022781:Hepatocytes / Q000201:enzymology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019897:Periplasm / Q000737:chemistry; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins
chemical_list: D000907:Antibodies, Bacterial; D011994:Recombinant Proteins; D002374:Catalase