Site-directed mutagenesis of La protease. A catalytically active serine residue

Abstract

Comparative sequence analysis of Escherichia coli ATP-dependent La protease led to the suggestion that Ser679 is the catalytically active enzyme residue. Site-directed mutagenesis Ser679----Ala, investigation of the cells containing the mutant plasmid, and study of the partially purified mutant protein produced results in favour of this suggestion.