Genetic features of circular bacteriocins produced by Gram-positive bacteria.
This review highlights the main genetic features of circular bacteriocins, which require the co-ordinated expression of several genetic determinants. In general terms, it has been demonstrated that the expression of such structural genes must be combined with the activity of proteins involved in maturation (cleavage/circularization) and secretion outside the cell via different transporter systems, as well as multifaceted immunity mechanisms essential to ensuring the bacteria's self-protection against such strong inhibitors. Several circular antibacterial peptides produced by Gram-positive bacteria have been described to date, including enterocin AS-48, from Enterococcus faecalis S-48 (the first one characterized), gassericin A, from Lactobacillus gasseri LA39, and a similar one, reutericin 6, from Lactobacillus reuteri LA6, butyrivibriocin AR10, from the ruminal anaerobe Butyrivibrio fibrisolvens AR10, uberolysin, from Streptococcus uberis, circularin A, from Clostridium beijerinckii ATCC 25752, and subtilosin A, from Bacillus subtilis. We summarize here the progress made in the understanding of their principal genetic features over the last few years, during which the functional roles of circular proteins with wide biological activity have become clearer.
Departmento de Microbiología, Facultad de Ciencias, Universidad de Granada, Fuentenueva s/n, Granada, Spain. mmaqueda@ugr.es
Mercedes
M
Maqueda
Marina
M
Sánchez-Hidalgo
Matilde
M
Fernández
Manuel
M
Montalbán-López
Eva
E
Valdivia
Manuel
M
Martínez-Bueno
D000595:Amino Acid Sequence; D001430:Bacteriocins / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D024881:Drug Resistance, Bacterial / Q000235:genetics; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D006094:Gram-Positive Bacteria / Q000235:genetics*; D005810:Multigene Family / Q000235:genetics; D017422:Sequence Analysis, DNA
D001430:Bacteriocins; C466236:enterocin AS-48, Enterococcus faecalis