Identification of LicC activity in pneumococcal infection

AIM:To clone and express licC and its truncated form genes(25 amino acids from 3'-terminus were deleted and named △LicC)of Streptococcus pneumoniae,analyze the enzymatic activities of the proteins. METHODS:The recombinant plasmid pQE80-licC,pQE80-△licC were constructed,and the target proteins were expressed in E.coli BL21 under isopropy-β-D-thiogalactoside(IPTG)induction. The proteins' activities were determined using bioluminescence test based on firefly luciferase assay system. RESULTS:The prokaryotic expression vector pQE80-licC,pQE80-△licC were successfully constructed and identified.The soluble proteins were obtained through inducing expression in E.coli BL21.It was showed that the activity of △LicC was markedly lower than that of LicC (P0.05). CONCLUSION:The homemade bioluminescence assay method can miner the activity of LicC reliably and accurately. The important role of 25 amino acids from 3'-terminus for the activity of LicC was confirmed,and it was suggested that suppressing of LicC maybe was a useful method for treatment S.pneumococcal infection,especially drug resistant strain.