Transcription and genetic analyses of a putative N-acetylmuramyl-l-alanine amidase in Borrelia burgdorferi


  • Editor: Robert Burne

Correspondence: Chunhao Li, Department of Oral Biology, State University of New York at Buffalo, 3435 Main Street, Buffalo, NY 14214-3092, USA. Tel.: +1 716 829 6014; fax: +1 716 829 3942; e-mail:


In this study, a putative N-acetylmuramyl-l-alanine amidase gene (bb0666) was identified in the genome of the Lyme disease spirochete Borrelia burgdorferi. This protein shares c. 30% identity with its counterparts from other bacteria. Reverse transcriptase-PCR analysis showed that bb0666 along with two other genes (bb0665 and bb0667) are cotranscribed with the motility and chemotaxis genes. This newly identified operon is termed as pami. Sequence and primer extension analyses showed that pami was regulated by a σ70-like promoter, which is designated as Pami. Transcriptional analysis using a gene encoding green fluorescence protein as a reporter demonstrated that Pami functions in both Escherichia coli and B. burgdorferi. Genetic studies showed that the Δbb0666 mutant grows in long chains of unseparated cells, whose phenotype is similar to its counterparts in E. coli. Taken together, these results demonstrate that bb0666 is a homolog of MurNac-LAAs that contributes to the cell division of B. burgdorferi.