Abstract
Although structure and function of PSI complex have been intensively investigated, the molecular mechanism for synthesis of PSI complex still remains elusive. The chloroplast-encoded Ycf4 is essential for assembly of PSI complex and is a part of a large complex of 700kDa in the green alga Chlamydomonas reinhardtii. We have successfully applied TAP-tag technology for purification of the complex containing Ycf4. NaBr-washed thylakoid membrane were solubilized with DM and the resulting extracts were directly applied onto a two-step affinity column chromatography. The purified complex contains six polypeptides with apparent molecular masses ranging from 16 to 64 kDa. Immunochemical detection and N-terminal amino acid sequencing revealed that 28 kDa and 20 kDa polypeptides are Ycf4 and PsaF, respectively. The determination of N-terminal amino acid sequencing of the other polypeptides is under progress.
