Polypeptides of ATP synthase

The CFi complex is composed of five different polypeptides in all plants examined so far. There is some variation in the reported values of the polypeptides from different plants, and, although some of the variation may be due to the use of different electrophoretic techniques, there appear to be real differences in the sizes of some of the individual polypeptides. The sizes of the polypeptides of wheat CF, are a, 58 kDa /3, 57kDa y, 38 kDa S, 25 kDa and e, 14 kDa [141]. There appears to be considerable variation in the size of the S subunit, which is reported to be 19.5 kDa in spinach [142]. The sizes of the polypeptides of CFj are similar to those of the E. coli Fj, and it appears that the chloroplast and bacterial polypeptides are structurally and functionally homologous [143]. The stoichiometry of the polypeptides of CF, is believed to be 3a 3j8 ly 15 le, as in E. coli. 

The polypeptide composition of CFq is deduced from the polypeptide composition of the purified ATP synthase preparations. CFq appears to be composed of four different polypeptides [140], although these may not all be resolved as separate bands by SDS-polyacrylamide gel electrophoresis. This led to the belief that there were only three polypeptides in CFq, as in the E. coli Fq complex, and these 

---