FIGURE 1: Types of cardiolipin (CL) synthases and their reaction mechanisms. (A) CLS belonging to the structural family of CDP-alcohol phosphatidyltransferases (CAP) catalyze an irreversible reaction between phosphatidyl glycerol (PG) and cytidine diphosphate diacylglycerol (CDP-DAG) to form CL and CMP, whereas CLS of the phospholipase D (PLD) type catalyzes a reversible transphosphatidylation reaction, using one molecule of PG together with another phosphatidyl donor (PG, PE, see main text) to form CL. (B) Schematic representation of the domain arrangement of CLS from yeast (S. cerevisiae Crd1; CAP-type) and T. brucei (TbCLS; PLD-type). The predicted transmembrane domains and conserved functional domains are indicated.