Abstract
Cloning and nucleotide sequence analysis showed that in Helicobacter pylori the gene encoding topoisomerase I ( topA) lies about 170 nucleotides upstream from flaB, a gene encoding one of the two flagellin proteins that is required for virulence. The topA and flaB genes are divergently transcribed. The orientation and spatial relationship between flaB and topA are remarkably conserved among strains of a bacterium in which genomic rearrangements are common. The deduced amino acid sequence of topoisomerase I revealed four zinc finger motifs, one more than has been reported previously for the Escherichia coli homologue. The additional motif, which is near the C-terminus of the protein, appears to be essential for function since mutations in that region are lethal. These data show that TopA proteins can be divided into several classes on the basis of zinc finger motifs and raise the interesting possibility that the H. pylori enzyme has local topological effects focussed on a flagellin gene.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
