Conservative region of the genes encoding four adhesins of Helicobacter pylori: cloning, sequence analysis and biological information analysis.
OBJECTIVE
To clone the conserved regions of the genes encoding the 4 adhesins (BabA, AlpA, AlpB and HopZ) of Helicobacter pylori (H. pylori) and analyze their sequences and biological information, thus facilitating further research in the molecular mechanism and immunogenicity of H. pylori adhesins.


METHODS
Common conserved region (designated as CB) was identified from the confirmed sequences (by ANTHEPROT V4.3c software package) of the 4 adhesin proteins. Their DNA sequences were deduced, according to which primers specific to CB were designed for subsequent PCR, and the products were inserted directionally into pET-22b(+) vector to construct recombinant clones of the conserved region. The DNA sequences were determined with the basic local alignment sequence tool (BLAST) and the biological properties analyzed with ANTHEPROT V4.3c software package.


RESULTS
The recombinant plasmid containing the CB sequence was constructed. DNA sequencing showed an open reading frame of 588 bp in length, encoding 195 amino acids. The homogencity of conservative region of the 4 adhesion genes was above 50%. The corresponding protein possessed a relative molecular mass (Mr) of 22 500 as predicted by ANTHEPROT V4.3c software prediction, with excellent antigenicity and hydrophobicity. There were 836 767 sequences analyzed with BLAST, in which those with homogencity of 40% with the identified CB sequence were categorized into H. pylori sequences.


CONCLUSIONS
There are conservative regions in the 4 adhesin genes with similar homogencity, suggesting similar molecular basis for adhesion of the adhesins. Biological information analysis indicates that CB has excellent immunogenicity and strict species specificity.
Bai
Yang
Y
Institute for Digestive Diseases of PLA, Nanfang Hospital, First Military Medical University, Guangzhou 510515, China.
Zhang
Ya-Li
YL
Wang
Ji-De
JD
Lin
Huan-Jian
HJ
Zhang
Zhao-Shan
ZS
Zhou
Dian-Yuan
DY
D018829:Adhesins, Bacterial / Q000235:genetics*; D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics*; D003001:Cloning, Molecular; D017124:Conserved Sequence; D004269:DNA, Bacterial / Q000032:analysis; D015252:Deoxyribonucleases, Type II Site-Specific; D029968:Escherichia coli Proteins / Q000235:genetics*; D005798:Genes, Bacterial; D016480:Helicobacter pylori / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D010957:Plasmids; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000235:genetics*
D018829:Adhesins, Bacterial; C086513:AlpA protein, E coli; C470179:AlpA protein, Helicobacter pylori; C119772:AlpB protein, Helicobacter pylori; C400429:BabA protein, Helicobacter pylori; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C121269:HopZ protein, Helicobacter pylori; D014157:Transcription Factors; C052380:endodeoxyribonuclease NcoI; D015252:Deoxyribonucleases, Type II Site-Specific; C038565:GCGGCCGC-specific type II deoxyribonucleases