Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: September 18, 2003
Publication Date: N/A
Technical Abstract: Leptospirosis is one of the most widespread bacterial zoonoses in the world. The etiological agents of leptospirosis are members of a diverse genus, Leptospira. Few virulence factors have been identified among pathogenic Leptospira. One potential virulence factor is sphingomyelinase, an enzyme that lyses erythrocytes. Genes related to a sphingomyelinase cloned from L. borgpetersenii serovar hardjo are found throughout pathogenic Leptospira spp., and each strain often has several copies of related, but distinct, genes. These findings suggest sphingomyelinase may play an important role in the survival of these bacteria in vivo. In the present study we identified and characterized three sphingomyelinase genes from the L. borgpetersenii serovar hardjo genome, sphA, sphB, and sphC. SphA, characterized elsewhere, and SphC each possess a single transmembrane domain and may expose the active portion of the protein on the cell surface. SphB is unusual, having a long, serine-rich, repeat region between the first and second of three transmembrane domains. The function of these repeats is unknown. Alignment of SphA, SphB, and SphC with spingomyelinases from other bacteria revealed extensive regions of similarity. SphC shares less similarity to bacterial sphingomyelinases, but several amino acid residues are well conserved. These residues may help locate functional regions of these proteins. The potential role of sphingomyelinases in leptospirosis will be presented.