Background: Helicobacter pylori encodes numerous outer membrane proteins (OMPs), but only a few have been characterized in depth. Deletion, duplication, and allelic variation of many of the H. pylori OMPs have been reported, which suggests that these proteins may play key roles in host adaptation. Herein, we characterize the variation observed within the Hom family of OMPs in H. pylori obtained from two geographically distinct populations. Materials and Methods: PCR genotyping of the hom genes was carried out using clinical isolates from South Korea and the United States. A combination of statistical, phylogenetic, and protein modeling analyses was conducted to further characterize the hom variants. Results: Variations in the closely related hom genes, homA and homB, occur in regions that are predicted to encode environmentally exposed loops. A similar phenomenon is true for homCS as compared to homCL. Conversely, little variation was observed in homD. Certain variants of the Hom family of proteins were more prominent in isolates from the Korean population as compared to isolates from the United States. Conclusion: En masse, our data show that the homA, homB, and homC profiles vary based upon the geographic origin of the strain; however, the fourth member of the hom family, homD, is more highly conserved. Additionally, protein topology modeling showed that many of the less well-conserved regions between homA and homB and between homCS and homCL corresponded to predicted environmentally exposed loops, suggesting that the divergence of the Hom family may be due to host adaptation/pressure.
Bibliographical noteFunding Information:
National Research Foundation of Korea, Grant/Award Number: 2017R1A2B4008960; National Institutes of Health, Grant/Award Number: R21AI121517
The contents of this article are solely the responsibility of the authors and do not necessarily represent the official views of the Department of Defense, the Uniformed Services University, or the NIH. We would like to thank Dr. Richard Peek and Judith Romero-Gallo for providing the AH strains and Dr. In-Sik Chung for the collection of KH strains. We would like to acknowledge Dr. Beth Carpenter and Jeannette M. Whitmire for critical reading of the manuscript and constructive comments. The research conducted in the laboratory of DSM is supported by NIH grant R21AI121517 (to DSM). This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF, http://www.nrf.re.kr) funded by the Ministry of Science, ICT and Future Planning (2017R1A2B4008960) (to JHC).
© 2018 John Wiley & Sons Ltd
All Science Journal Classification (ASJC) codes
- Infectious Diseases