Abstract
The chloroplast-encoded Ycf4 is an essential polypeptide for assembly of photosystem I (PS I) complex in the green alga Chlamydomonas reinhardtii. However, it remains to be addressed how Ycf4 plays a role in assembly of PS I complex. To understand the function of Ycf4, we have engineered Ycf4 of the green alga Chlamydomonas reinhardtii by chloroplast transformation. We have replaced Arg at position of 9, 10, 17 and 18 by Gln, respectively, to delete these conserved positive charge (R9Q, R10Q, R9/10Q, R17Q, R18Q and R17/18Q). A series of deletion mutants were also generated in which every two amino acid residues are deleted from the N-terminus of Ycf4, and two mutants were generated in which a part of the hydrophilic region between two putative transmembrane helices. We will report on effect of these mutations on assembly of PS I complex.
