The LanC-like protein superfamily encompasses a highly divergent group of peptide-modifying enzymes, including the eukaryotic and bacterial lanthionine synthetase C-like proteins (LanC) [, , ]; subtilin biosynthesis protein SpaC from Bacillus subtilis [, ]; epidermin biosynthesis protein EpiC from Staphylococcus epidermidis []; nisin biosynthesis protein NisC from Lactococcus lactis [, , ]; GCR2 from Arabidopsis thaliana []; and many others. The 3D structure of the lantibiotic cyclase from L. lactis has been determined by X-ray crystallography to 2.5A resolution []. The globular structure is characterised by an all-alpha fold, in which an outer ring of helices envelops an inner toroid composed of 7 shorter, hydrophobic helices. This 7-fold hyrophobic periodicity has led several authors to claim various members of the family, including eukaryotic LanC-1 and GCR2, to be novel G protein-coupled receptors [, ]; some of these claims have since been corrected [, , ]. The C terminus of the lantibiotic biosynthesis protein LanM is homologous to LanC [, ]. LanC-like protein 1 (included in this family) has been shown to function as a glutathione transferase, and as such has been renamed to Glutathione S-transferase LANCL1 [].
