Class I The Lanthionine Containing Lantibiotic Bacteriocins

The term lantibiotic (Schnell et al. 1988 Jung 1991) refers to the diverse array of bacterial antibiotic peptides that contain the non-genetically encoded amino acids lanthionine (Lan) and or 3-methyllanthionine (MeLan), as well as various other highly modified amino acids, commonly including the 2,3-unsaturated amino acids dehydroalanine (Dha) and dehydrobutyrine (Dhb). All of the lantibiotics currently described are thought to be produced as ribo-somally synthesized precursor peptides, which...

Colicin D A Possible Intermediate Between Pyocins and Colicins

The modular design of colicins and pyocins provides flexibility for generating new bacteriocins by recombination mechanisms. As described above, colicin B is a classic example, with colicin D-like translocation and receptor-binding domains and a colicin A Y-like pore-forming domain. Similarly, translocation and DNase domains of pyocins S1 and S2 are homologous whereas their receptor-binding domains have been acquired from different sources. Thus, Fig. 3.8 Nucleotide alignment of regulatory...

Models of Colicin Evolution

Riley and co-workers have extensively studied the evolution of colicins, and it is the result of these efforts that colicins are being recognized as a model system for the evolution of Gram-negative bacteriocins Riley 1993a, 1993b, 1998 Riley et al. 1994, 2000 Tan and Riley 1996, 1997a Riley and Wertz 2002a, 2002b . Two mechanisms - diversifying selection and recombination -have been proposed to explain how these molecules have evolved Tan and Riley 1997b . According to the diversifying...