ISOLATION AND ANALYSIS OF NOVEL MUTANTS OF ESCHERICHIA-COLI PRLA (SECY)

Plasmid libraries of prlA mutants containing single-base-pair changes throughout the gene were generated by in vitro random mutagenesis. The prlA mutations capable of suppressing the secretion defect of LamB ca used by mutations in the LamB signal peptide were selected and analyze d. Together with additional mutations generated by site-directed mutag enesis, a number of novel prlA mutations and/or suppressors were ident ified. These mutations provide the starting points for studying the re lationship of structure and function of PrlA in its interaction with L amB and/or other component(s) in the Escherichia coli protein secretio n-translocation complex.