Outer membrane proteome of Leptospira; revealing the bottom of iceberg

Leptospira, the causative agent of leptospirosis is known to have several proteases with potential to degrade extracellular matrix. However, a multipronged approach to identify, classify, characterize and elucidate their role has not been attempted. In this study, we carried out in-depth proteomic analysis of Triton X-114 fractions of Leptospirainterrogansusing high-resolution LC-MS/MS. Our analysis resulted in the identification of We have identified 2957 proteins that account 80.6% proteins of Leptospira and their subcellular distribution. The analysis showed differential enrichment of proteins in aqueous, detergent and pellet fractions with respect to the subcellular localization predicted by on CELLO v.2.5. It is found that highest number of OMP and pathogenic protein species were found in aqueous and pellet representing the cytoplasm and inner membranewhile the detergent fraction representing the OM contain highest amount of OMPs and pathogenic proteins even though the number of protein species were less. Thus the higher number of OMP and pathogenic proteins in the inner compartments of the cell carry the possibility of their deployment on the OM in abundance under pathogenic conditions.