Ah-Young Shina, Yun-Jeong Hana, Pill-Soon Songb, Jeong-Il Kima
a Department of Biotechnology and Kumho Life Science Laboratory, Chonnam National University, Gwangju 500-757, Republic of Korea
b Faculty of Biotechnology and Subtropical Horticulture Research Institute, Jeju National University, Jeju 690-756, Republic of Korea
Corresponding author : Jeong-Il Kim
We have successfully developed a system to produce full-length plant phytochrome assembled with phytochromobilin in Pichia pastoris by co-expressing apophytochromes and chromophore biosynthetic genes, heme oxygenase (HY1) and phytochromobilin synthase (HY2) from Arabidopsis. Affinity-purified phytochrome proteins from Pichia cells displayed zinc fluorescence indicating chromophore attachment. Spectroscopic analyses showed absorbance maximum peaks identical to in vitro reconstituted phytochromobilin-assembled phytochromes, suggesting that the co-expression system is effective to generate holo-phytochromes. Moreover, mitochondria localization of the phytochromobilin biosynthetic genes increased the efficiency of holophytochrome biosynthesis. Therefore, this system provides an excellent source of holophytochromes, including oat phytochrome A and Arabidopsis phytochrome B.
Keywords : Holophytochrome; Chromophore; Phytochromobilin; Heme oxygenase; Bilin reductase