TOPOGRAPHY OF CARDIOLIPIN SYNTHASES IN THE PLASMA MEMBRANE OF <I>E. coli</I>
The mutant E. coli strains with deletions in the genes of cardiolipin syntases ( cls) and mannitol permease A were constructed using the P1 phage transduction. Cardiolipin was detected under the activity of ClsB and/or ClsC cardiolipin syntases using TLC methods with P 32 radiolabelling. New lipids such as phosphatidyl mannitol were found when ClsB or ClsC cardiolipin syntases were active. Diphosphatidyl mannitol was found when only ClsB was active. Consequently, the active centers of ClsB and ClsC face the periplasmic space, where enzymes convert the synthesized phosphatidylglycerol to cardiolipin. Accordingly, the active center ClsA faces the cytoplasm.