(Chris) Lok-To Sham
B.Sc., Molecular Biotechnology, the Chinese University of Hong Kong
M. Phil., Biology, the Chinese University of Hong Kong, Hong Kong
Ph.D., Microbiology, Indiana University Bloomington, IN
While most of the players in the pathway have been identified and characterized, the identity of the flippase responsible for translocating the final lipid-linked PG precursor called lipid II across the cytoplasmic membrane has remained controversial. The debate has endured because there is no available assay for lipid-II flippase activity in vivo. Using the fact that bacteriocin colicin M (ColM) only degrades flipped lipid II, we developed an in vivo lipid-II flippase assay that demonstrate MurJ is required for lipid II translocation. From these data and the fact that MurJ has a solvent exposed cavity required for its function, my work indicates that MurJ is most likely to be the lipid II flippase in E. coli.