Quantitative Lipoproteomics in Clostridium difficile Reveals a Role for Lipoproteins in Sporulation

This is the final version of the article. Available from Elsevier via the DOI in this record.Bacterial lipoproteins are surface exposed, anchored to the membrane by S-diacylglyceryl modification of the N-terminal cysteine thiol. They play important roles in many essential cellular processes and in bacterial pathogenesis. For example, Clostridium difficile is a Gram-positive anaerobe that causes severe gastrointestinal disease; however, its lipoproteome remains poorly characterized. Here we describe the application of metabolic tagging with alkyne-tagged lipid analogs, in combination with quantitative proteomics, to profile protein lipidation across diverse C. difficile strains and on inactivation of specific components of the lipoprotein biogenesis pathway. These studies provide the first comprehensive map of the C. difficile lipoproteome, demonstrate the existence of two active lipoprotein signal peptidases, and provide insights into lipoprotein function, implicating the lipoproteome in transmission of this pathogen.T.C. was funded by an EPSRC grant to the Institute of Chemical Biology, Imperial College London. A.K.-S. was funded by a European Union Seventh Framework Program (EU MCN Grant agreement 237942)