Screening of angucycline antibiotics as potential drug candidates against MRSA by docking analysis

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major pathogens, mainly caused by hospital infections. It has also developed resistance to various antibiotics such as β-lactams, aminoglycosides, and quinolones. Therefore, it is necessary to discover new drugs against MRSA infections by targeting their virulent factors. It is through that staphyloxanthin is a virulent factor of MRSA as dehydrosqualene synthase (CrtM) involves in the first step of its biosynthesis. For this reason, the CrtM enzyme is a potential target against MRSA by weakening its virulence. Actinomycetes are Gram-positive, filamentous, bacteria known for their significant capacity for the production of secondary metabolites with diverse biological activities. Among these, the polycyclic aromatic compounds which are known as angucycline antibiotics are the largest group of type-II polyketide synthase. The present study involves the evaluation of the inhibitory activity of 157 actinomycete-produced angucyline compounds against MRSA CrtM enzyme (PBD ID: 3ACW and 3W7F) by docking studies. Docking analysis demonstrate that among the attempted compounds; Moromycin A (56), Saquayamycin B (58), Saquayamycin A (145) and Saprolmycin E (29) have good interactions with CrtM with higher dock scores;-14.8, -14.4, -13.7, and -13.7 kcal/mol, respectively, when compared with substrate farnesyl diphosphate (-8.3 kcal/mol) and one of current inhibitors BPH-651 (-11.5 kcal/mol). However further studies, molecular dynamic simulations and in vitro investigations are required to achieve a conclusion.