CLONING AND EXPRESSION OF THE BORRELIA-BURGDORFERI LON GENE

The ATP-dependent protease Lon (La) of Escherichia coli degrades abnor mal proteins and is involved in the regulation of capsular polysacchar ide synthesis. In addition, mutations in the E. coli ion gene suppress temperature-sensitive mutations in other genes. The ion gene of Borre lia burgdorferi, encoding a homolog of the Lon protease, has been clon ed and sequenced. The gene encodes a protein of 806 amino acids. The d educed amino acid sequence of the B. burgdorferi Lon protease shares s ubstantial sequence identity with those of other known Lon proteases. The transcription start point of the B. burgdorferi ion gene was ident ified by primer extension analysis and the potential promoter did not show similarities to the consensus heat-shock promoter in E. coli. The 5'-end of the B. burgdorferi ion gene appears to suppress the tempera ture-sensitive phenotype of an E. coli lpxA mutant. (C) 1997 Elsevier Science B.V.