FIGURE 1.

Tafazzin requires detergent to react with PC and MLCL in vitro. GST-tagged yeast tafazzin was incubated with liposomes containing 72 nmol of PC and 8 nmol of MLCL in a total volume of 0.1 ml. The formation of CL was measured by mass spectrometry. A, the acyl donors PC 18:1/18:1 and PC 18:2/18:2 were compared in the absence and presence of 0.2% Triton X-100. Transacylation activity with either substrate required detergent. B, CL was measured after 30-min incubation in the presence of PC 18:1/18:1 and different concentrations of Triton X-100. The detergent increased the transacylation activity. C, the reaction was performed for 30 min in the presence of 0.12% Triton X-100, liposomes were separated from micelles, and lipids were analyzed in the two fractions. The substrate (MLCL) was recovered in both fractions, but the product (CL) was recovered mostly in micelles. The data are mean values of the indicated number of experiments (n); the error bars represent S.E.