Production of Full-Length Pea Phytochrome A (Type I) Apoprotein by Yeast Expression System

Pea phytochrome A (type I phytochrome) cDNA spanning the completecoding region was expressed using a yeast expression system.Anti-pea phytochrome A (phyA) antibodies that recognize differentepitopes located from the N- to the C-terminus of the moleculedetected a single product with a molecular weight of 120 kDaas native pea phyA in western blot analysis of the yeast lysate.This indicated that the yeast system produced full-length peaphyA apoprotein (PHYA). The yield of PHYA was 0.037% of totalyeast protein. When size exclusion column chromatography wasperformed, PHYA expressed in yeast was detected at around 450kDa although pea phyA was detected at 400 kDa, suggesting thatPHYA exists in a nonglobular dimeric form but its conformationis slightly different than that of native pea phyA. (Received April 22, 1991; Accepted June 20, 1991)