The newly characterized colicin Y provides evidence of positive selection in pore-former colicin diversification

• Published in: Microbiology (Society for General Microbiology) 2000-07, Vol.146 (7), p.1671-1677
• Main Authors: Riley, M. A, Cadavid, Luis, Collett, Marc S, Neely, Melody N, Adams, Mark D, Phillips, Cheryl M, Neel, James V, Friedman, David
• Format: Article
• Language: English
• Subjects: Bacteriology; Biological and medical sciences; colicin Y; Colicins - classification; Colicins - genetics; Colicins - metabolism; DNA, Bacterial - genetics; Escherichia coli; Escherichia coli - genetics; Escherichia coli - metabolism; Evolution, Molecular; Fundamental and applied biological sciences. Psychology; Humans; Indians, South American; Microbiology; Molecular Sequence Data; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Phylogeny; Plasmids - genetics
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/00221287-146-7-1671

Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06511, USA 1 The Institute for Genomic Research, 9712 Medical Center Dr., Manassas, VA 20850, USA 2 Dept of Human Genetics 3 and Dept of Microbiology and Immunology 4 , University of Michigan, Ann Arbor, MI 48109, USA Author for correspondence: David Friedman. Tel: [phone]. Fax: [phone]. e-mail: davidfri{at}umich.edu Two evolutionary mechanisms have been proposed in the process of protein diversification of the large family of antimicrobial toxins of Escherichia coli , known as the colicins. Data from previous studies suggest that the relatively rare nuclease colicins appear to diversify primarily through the action of positive selection, whilst the more abundant pore-former colicins appear to diversify through the action of recombination. The complete DNA sequence of the newly characterized colicin plasmid, pCol-Let, isolated from a Yanomama Indian of South America, is presented here. This plasmid encodes a newly identified pore-former colicin, colicin Y. DNA and protein sequence comparisons of the colicin Y gene cluster and the encoded proteins with those of published pore-former colicins provide the first evidence that positive selection may also act to increase pore-former colicin diversity. Keywords: colicins, positive selection, evolution, plasmid, Yanomama Indians During the time this manuscript was being prepared for publication, our colleague James V. Neel passed away. The other authors wish to dedicate this work to his memory. The GenBank accession number for the sequence reported in this paper is AF197335 . b Present address: Viropharma Incorporated, 405 Eagleview Blvd, Exton, PA 19341, USA. c Present address: Washington University Medical School, Molecular Biology, Campus Box 8230, St Louis, MO 62110, USA.