Elucidation of the genetic mechanisms contributing to moenomycin resistance in actinobacteria

Aim. Moenomycins are phosphoglycolipid antibiotics produced almost exclusively by representatives of genus Streptomyces. These antibiotics directly inhibit peptidoglycan glycosyltransferases and are extremely active against cocci. Here we studied how antibiotic-producing actinobacteria protect themselves from toxic action of moenomycins. Methods. Microbiological and molecular genetic approaches were combined to reveal intrinsic levels and distribution of moenomycin resistance across actinobacteria genera, and to pinpoint genes contributing to moenomycin resistance in model strain Streptomyces coelicolor M145. Results. Out of 51 actinobacterial species (90 % of which Streptomyces) being tested, only Streptomyces albus J1074 turned out to be highly susceptible to moenomycin A, although resistant variants can be facilely raised. Several classes of mutations increased level of susceptibility of S. coelicolor to moenomycin, although in no case the latter was equal to what we observed in J1074 strain. Conclusions. Moenomycin resistance is widespread across actinobacteria, and it most likely is caused by a combination factors, such as richly decorated cell wall and organization of divisome apparatus. It is possible that moenomycin resistance mechanisms operating in actinobacteria and pathogenic cocci are different. Keywords: moenomycin, antibiotic resistance, peptidoglycan.

The molecular biology of moenomycins: towards novel antibiotics based on inhibition of bacterial peptidoglycan glycosyltransferases

Moenomycins are phosphoglycolipid antibiotics and the only known natural product inhibitors of peptidoglycan glycosytransferases (PGTs). Techniques that would allow facile diversification of the moenomycin structure would facilitate the development of novel antibiotics, which are urgently needed in the wake of multidrug resistant bacterial infections. The cloning and initial characterization of the moenomycin biosynthetic genes has already redefined the minimal moenomycin pharmacophore and now opens the door for the biocombinatorial generation of bioactive moenomycin fragments. Here, we highlight the importance of research on the genetic mechanisms that regulate moenomycin biosynthesis and that confer moenomycin resistance to bacteria in the development of novel anti-infectives based on PGT inhibition.