Rhomboid homologs in mycobacteria: insights from phylogeny and genomic analysis

BMC Microbiology

Research Article

Henry W Boom¹  Moses Okee²  Alfred Okeng²  David P Kateete²  Fred A Katabazi²  Moses L Joloba²  Kathleen D Eisenach³  Jeniffer Asiimwe⁴ 

[1] Case Western Reserve University, Cleveland, OH, USA;Department of Medical Microbiology, School of Biomedical Sciences, Makerere University College of Health Sciences, Kampala, Uganda;Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR, USA;Department of Veterinary Parasitology & Microbiology, Faculty of Veterinary Medicine, Makerere University, Kampala, Uganda;

关键词: Mycobacterium Avium Complex;    Buruli Ulcer;    Mycobacterial Species;    Pathogenic Mycobacterium;    Mycobacterial Genome;   

DOI  :  10.1186/1471-2180-10-272

 received in 2010-06-25, accepted in 2010-10-29,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundRhomboids are ubiquitous proteins with diverse functions in all life kingdoms, and are emerging as important factors in the biology of some pathogenic apicomplexa and Providencia stuartii. Although prokaryotic genomes contain one rhomboid, actinobacteria can have two or more copies whose sequences have not been analyzed for the presence putative rhomboid catalytic signatures. We report detailed phylogenetic and genomic analyses devoted to prokaryotic rhomboids of an important genus, Mycobacterium.ResultsMany mycobacterial genomes contained two phylogenetically distinct active rhomboids orthologous to Rv0110 (rhomboid protease 1) and Rv1337 (rhomboid protease 2) of Mycobacterium tuberculosis H37Rv, which were acquired independently. There was a genome-wide conservation and organization of the orthologs of Rv1337 arranged in proximity with glutamate racemase (mur1), while the orthologs of Rv0110 appeared evolutionary unstable and were lost in Mycobacterium leprae and the Mycobacterium avium complex. The orthologs of Rv0110 clustered with eukaryotic rhomboids and contained eukaryotic motifs, suggesting a possible common lineage. A novel nonsense mutation at the Trp73 codon split the rhomboid of Mycobacterium avium subsp. Paratuberculosis into two hypothetical proteins (MAP2425c and MAP2426c) that are identical to MAV_1554 of Mycobacterium avium. Mycobacterial rhomboids contain putative rhomboid catalytic signatures, with the protease active site stabilized by Phenylalanine. The topology and transmembrane helices of the Rv0110 orthologs were similar to those of eukaryotic secretase rhomboids, while those of Rv1337 orthologs were unique. Transcription assays indicated that both mycobacterial rhomboids are possibly expressed.ConclusionsMycobacterial rhomboids are active rhomboid proteases with different evolutionary history. The Rv0110 (rhomboid protease 1) orthologs represent prokaryotic rhomboids whose progenitor may be the ancestors of eukaryotic rhomboids. The Rv1337 (rhomboid protease 2) orthologs appear more stable and are conserved nearly in all mycobacteria, possibly alluding to their importance in mycobacteria. MAP2425c and MAP2426c provide the first evidence for a split homologous rhomboid, contrasting whole orthologs of genetically related species. Although valuable insights to the roles of rhomboids are provided, the data herein only lays a foundation for future investigations for the roles of rhomboids in mycobacteria.

【 授权许可】

Unknown   
© Kateete et al; licensee BioMed Central Ltd. 2010. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.