FIG. 1.

PCR mutagenesis of the lipoprotein signal peptidase cleavage site of LipL41. In step 1, the lipL41 gene of L. kirschneri was PCR amplified and inserted into pET15b. In step 2, a portion of pET15b-LipL41 plasmid was amplified by using primers that alter the sequence encoding the two amino acids preceding cysteine. The mutagenized FspI-ApaI fragment was then inserted into pET15b-LipL41. The location of the FspI site is underlined in the boxed sequences, which also show the amino acid sequences commencing with the leucine of the lipoprotein signal peptidase cleavage site before (LGNC) and after (LAGC) PCR mutagenesis.