Cloning of the gene encoding urease subunit A in Helicobacter pylori

The gene encoding urease subunit A (ureA) of Helicobacter pylori (H. pylori) was cloned from H. pylori isolate by polymerase chain reaction (PCR). Sterile distilled water instead of DNA served as negative control. The nucleotide sequence of the amplified product was determined. Homologous analysis of the ureA against that reported by Clayton CL and the GenBank and SwissProt databases were performed with the BLAST program at the Genome Net through the Internet. 0.8 kb PCR product was amplified from all H. pylori clinical isolators. The nucleotide sequence of the ureA was determined. The nucleotide sequence of the ureA began with ATG as the initiation codon and terminated in TAA as stop codon. The coding regions had a 44% G + C content. The DNA sequence was 98% homologous to that reported by Clayton CL (688 out of 702 residues were identical). The derived amino-acid sequences of the ureA were 99% homologous to that reported by Clayton CL (232 out of 234 residues were identical). The nucleotide sequence and the predicted protein showed significant homology to ureA of H. pylori in the NCBI Entrez database.