Objective: To confirm the involvement of pqqL gene of Escherichia coli in PQQ biosynthesis, a pqqL deletion mutant of E. coli DH5alpha was constructed and investigated.
Methods: pqqL and kan gene were cloned and a linear targeting fragment pqqL-kan-pqqL was constructed in vitro. Then pqqL gene was knocked out and DH5alphadeltapqqL mutant was constructed by Red homologous recombination. The PQQ biosynthesis was compared between the mutant and its parential strain by detection of bio-activity of sorbose dehydrogenase with DCIP method.
Results: The DH5alphadeltapqqL deletion mutant was successfully constructed, and the result indicated that PQQ would be synthesized in pBCP162/DH5alphadeltapqqL and pMD19T Simple-pqqABCDE/DH5alpha, but not in pMD19T Simple-pqqABCDE/DH5alphadeltapqqL.
Conclusion: The function of pqqL gene in Escherichia coli is the same to that of pqqF gene.