Biochemical Characterization of the Staphylococcal Endolysin MV-L with Enhanced Activity Under Optimized Conditions...

Methicillin-resistant Staphylococcus aureus (MRSA) remains a major cause of difficult-to-treat infections, largely due to its multidrug resistance and capacity to form persistent biofilms on medical and industrial surfaces. Bacteriophage-derived endolysins have emerged as promising antibacterial agents, but many still require detailed biochemical characterization to support their potential applications. The present study describes the staphylococcal endolysin MV-L expression, purification, and functional analyses, evaluating its ability to control MRSA on surfaces and in biofilms. MV-L was recombinantly produced in Escherichia coli, purified by nickel affinity chromatography; its lytic activity against exponentially growing MRSA was assessed under different physicochemical conditions. Enzyme exhibited optimal activity in slightly alkaline conditions and moderate temperatures; its performance was strongly influenced by ionic strength and divalent cations. Under optimized conditions, MV-L showed markedly increased lytic efficiency and retained activity at low protein concentrations. Beyond planktonic cells, MV-L significantly reduced MRSA loads on glass and stainless steel and disrupted pre-formed biofilms on polystyrene. These findings highlight how buffer composition and ion availability critically modulate MV-L activity and support the concept that tailored endolysins can be integrated as complementary strategies for MRSA control, particularly in scenarios where conventional disinfectants and antibiotics are limited by resistance or poor efficacy against biofilms.