1.C.84 The Subtilosin (Subtilosin) Family

Subtilosin A is an antimicrobial peptide produced by Bacillus subtilis. It possesses bactericidal activity against a diverse range of bacteria, including Listeria monocytogenes (Maqueda et al., 2008). Structural studies have found that subtilosin A is posttranslationally modified. It interacts with the lipid head group region of bilayer membranes, and at high concentrations, induces leakage from lipid bilayers. Subtilosin A adopts a partially buried orientation in lipid bilayers, inducing conformational changes in the lipid headgroups and disordering in the hydrophobic regions of bilayers. Lipid perturbation is the consequence of subtilosin A binding to lipid bilayers, which results in membrane permeabilization at high peptide concentrations (Thennarasu et al., 2005). Mutational variants of Subtilosin A with increased hemolytic activity have been isolated (Huang et al., 2009). 

The sactibiotic subclass of bacteriocins contain characteristic cysteine sulphur to α-carbon linkages mediated through post-translational modifications.  They include subtilosin, thuricinCD, thuricin H, and propionicin F (TC# 1.C.94).  Thuricin CD is a narrow spectrum anit-Clostridium difficile sactibiotic.  Others target Listeria monocytogenes, Gardnerella vaginalis and other pathogens (Mathur et al. 2015).

The generalized transport reaction believed to be catalyzed by sactibiotics is:

small molecules (in) → small molecules (out)