title: The newly characterized colicin Y provides evidence of positive selection in pore-former colicin diversification.
abstract: 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.
authors.affiliation: Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06511, USA1.
authors.forename: M A
authors.initials: MA
authors.lastname: Riley
authors.affiliation: Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06511, USA1.
authors.forename: Luis
authors.initials: L
authors.lastname: Cadavid
authors.affiliation: Dept of Human Genetics3 and Dept of Microbiology and Immunology4, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: Marc S
authors.initials: MS
authors.lastname: Collett
authors.affiliation: Dept of Human Genetics3 and Dept of Microbiology and Immunology4, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: Melody N
authors.initials: MN
authors.lastname: Neely
authors.affiliation: The Institute for Genomic Research, 9712 Medical Center Dr., Manassas, VA 20850, USA2.
authors.forename: Mark D
authors.initials: MD
authors.lastname: Adams
authors.affiliation: The Institute for Genomic Research, 9712 Medical Center Dr., Manassas, VA 20850, USA2.
authors.forename: Cheryl M
authors.initials: CM
authors.lastname: Phillips
authors.affiliation: Dept of Human Genetics3 and Dept of Microbiology and Immunology4, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: James V
authors.initials: JV
authors.lastname: Neel
authors.affiliation: Dept of Human Genetics3 and Dept of Microbiology and Immunology4, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: David
authors.initials: D
authors.lastname: Friedman
mesh_terms: D003087:Colicins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D019143:Evolution, Molecular; D006801:Humans; D007199:Indians, South American; D008969:Molecular Sequence Data; D010802:Phylogeny; D010957:Plasmids / Q000235:genetics
chemical_list: D003087:Colicins; D004269:DNA, Bacterial