title: Cloning, nucleotide sequence, and expression of a gene encoding an adhesin subunit protein of Helicobacter pylori.
abstract: Gene hpaA, which codes for the receptor-binding subunit of the N-acetylneuraminyllactose-binding fibrillar hemagglutinin (NLBH) of Helicobacter pylori, was cloned and sequenced. The protein expressed by hpaA, designated HpaA, was identified as the adhesin subunit on the basis of its fetuin-binding activity and its reactivity with a polyclonal, monospecific rabbit serum prepared against NLBH purified from H. pylori. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis and Western blots (immunoblots) showed that the cloned adhesin has the same molecular weight (20,000) as that found on H. pylori. Also, HpaA contains a short sequence of amino acids (KRTIQK) which are all either identical or functionally similar to those which compose the sialic acid-binding motif of Escherichia coli SfaS, K99, and CFA/I. Affinity-purified antibody specific for a 12-residue synthetic peptide that included this sequence blocked the hemagglutinating activity of H. pylori and was shown by immuno-gold electron microscopy to react with almost transparent material on unstained H. pylori cells, which is consistent with previous observations concerning the location and morphology of the NLBH.
authors.affiliation: Department of Medicine, Baylor College of Medicine, Houston, Texas 77030.
authors.forename: D G
authors.initials: DG
authors.lastname: Evans
authors.forename: T K
authors.initials: TK
authors.lastname: Karjalainen
authors.forename: D J
authors.initials: DJ
authors.lastname: Evans
authors.forename: D Y
authors.initials: DY
authors.lastname: Graham
authors.forename: C H
authors.initials: CH
authors.lastname: Lee
mesh_terms: D018829:Adhesins, Bacterial; D000595:Amino Acid Sequence; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D005753:Gastric Mucosa / Q000378:metabolism / Q000382:microbiology; D005798:Genes, Bacterial; D016480:Helicobacter pylori / Q000235:genetics*; D006388:Hemagglutinins / Q000235:genetics*; D008969:Molecular Sequence Data; D011485:Protein Binding; D015183:Restriction Mapping; D000509:alpha-Fetoproteins / Q000378:metabolism
chemical_list: D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D006388:Hemagglutinins; C073899:adhesin, helicobacter; D000509:alpha-Fetoproteins