In vitro antibacterial activity of recombinant protein AtlM of Staphylococcal aureus / 中华微生物学和免疫学杂志

ABSTRACT

Objective To construct the recombinant protein AtlM ( rAtlM) of Staphylococcal au-reus through prokaryotic expression system and to investigate its antibacterial activity in vitro.Methods The specific primers were designed according to atlM gene sequence of Staphylococcal aureus recorded in Gen-Bank, and atlM gene was amplified by PCR from the Staphylococcal aureus strain (ATCC25923).The re-combinant plasmid pET-32а(+)/atlM was constructed and transformed into Transetta ( DE3 ) to express AtlM after induced by IPTG .The expressed protein AtlM was further analyzed by SDS-PAGE and purified by electroeluting of bag filter.The minimal inhibitory concentrations (MICs) of rAtlM to ATCC25923 and oxac-illin-resistant S.aureus strain were determined by the broth microdilution method .S.aureus ATCC25923 strain and oxacillin-resistant S.aureus strain (final concentration of 5×105 CFU/ml) were exposed to rAtlM (50 μg/ml) respectively to test its antibacterial activity in vitro.Results The recombinant protein AtlM was expressed and purified successfully with a relative molecular weight of 80 ×103 and a concentration of 1.25 mg/L.The MICs of rAtlM to ATCC25923 strain and oxacillin-resistant S.aureus strain were 8 μg/ml and 64 μg/ml, respectively.In vitro test showed that rAtlM had inhibitory effects on the growth of ATCC25923 strain and oxacillin-resistant S.aureus strain after 1 h of intervention (P=0.004 and P=0.026, respectively), which lasted to 5 h for ATCC25923 strain (P=0.012) and 3 h for oxacillin-resistant strain (P=0.001).Conclusion This study shows that rAtlM has a certain antibacterial effects on S.aureus ATCC25923 strain and oxacillin-resistant S.aureus strain, suggesting a possibility of serving as antimicrobial agent.