[Identification of LicC activity in pneumococcal infection]

To clone and express licC and its truncated form genes (25 amino acids from 3'-terminus were deleted and named deltaLicC) of Streptococcus pneumoniae, analyze the enzymatic activities of the proteins.

The recombinant plasmid pQE80-licC, pQE80-deltalicC were constructed, and the target proteins were expressed in E. coli BL21 under isopropy-beta-D-thiogalactoside (IPTG) induction. The proteins' activities were determined using bioluminescence test based on firefly luciferase assay system.

The prokaryotic expression vector pQE80-licC, pQE80-deltalicC were successfully constructed and identified.The soluble proteins were obtained through inducing expression in E. coli BL21. It was showed that the activity of deltaLicC was markedly lower than that of LicC (P<0.05).

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.