The Sactibiotic Subclass of Bacteriocins: An Update

The sactibiotics are a recently designated subclass of bacteriocins that contain characteristic cysteine sulphur to α -carbon linkages mediated through post-translational modifications. They are a relatively small subclass of bacteriocins compared to the most thoroughly studied lantibiotics. The sactibiotics that have been extensively studied thus far are thuricin CD, subtilosin A, thurincin H, and propionicin F. Despite their recent discovery, there have already been significant advances made in the study of sactibiotics, most notably the discovery of the narrow spectrum anti-Clostridium difficile sactibiotic, thuricin CD. In addition, scientists have gained insights into the mechanisms of action of the sactibiotic subtilosin A, which targets Listeria monocytogenes, Gardnerella vaginalis, and other pathogens. Also, the development of heterologous host systems and homologous expression and site-directed mutagenesis systems for the sactibiotic thurincin H have opened up many opportunities for further studies on this sactibiotic. These and other recent studies concerning the molecular biology, 3D structural elucidation, mode of action, self-protection mechanisms, and antimicrobial spectrum of the sactibiotic subgroup of bacteriocins are discussed in this review.