title: Restriction fragment length polymorphism in the adhesin gene hpaA of Helicobacter pylori.
abstract: OBJECTIVE
  To assess the degree of restriction fragment length polymorphism (RFLP) in the Helicobacter pylori adhesin gene hpaA and to determine the molecular basis of RFLP in this gene.
  
  
  METHODS
  A 375-bp, polymerase chain reaction-amplified internal sequence of hpaA, obtained from 50 different H. pylori isolates, was restricted with Sau3A and HinfI, individually. Polymerase chain reaction products representing different RFLP types were sequenced.
  
  
  RESULTS
  Seven different polymorphic types were found in hpaA. Base substitutions at only four positions, two in Sau3A and two in HinfI sites, account for all of the RFLP types, including the size of the restriction fragments determined by gel electrophoresis. Most, 90%, of the base substitutions are very conservative, i.e., either do not change the encoded amino acid or substitute a homologous amino acid, and cause no detectable antigenic or functional effect on hpaA. The region of hpaA encoding the receptor-binding motif was particularly well conserved.
  
  
  CONCLUSIONS
  RFLP typing of hpaA using Sau3A and HinfI provides an additional tool for comparing the genetic relatedness of H. pylori isolates collected during epidemiological and/or treatment studies.
authors.affiliation: Department of Medicine, Baylor College of Medicine, Houston, Texas, USA.
authors.forename: D G
authors.initials: DG
authors.lastname: Evans
authors.forename: D J
authors.initials: DJ
authors.lastname: Evans
authors.forename: H C
authors.initials: HC
authors.lastname: Lampert
authors.forename: D Y
authors.initials: DY
authors.lastname: Graham
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics*; D001483:Base Sequence; D005798:Genes, Bacterial; D016481:Helicobacter Infections / Q000382:microbiology; D016480:Helicobacter pylori / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length
chemical_list: D018829:Adhesins, Bacterial