TY - JOUR
T1 - Synergistic interactions between carotene ring hydroxylases drive lutein formation in plant carotenoid biosynthesis
AU - Quinlan, Rena F.
AU - Shumskaya, Maria
AU - Bradbury, Louis M.T.
AU - Beltrán, Jesús
AU - Ma, Chunhui
AU - Kennelly, Edward J.
AU - Wurtzel, Eleanore T.
PY - 2012/9
Y1 - 2012/9
N2 - Plant carotenoids play essential roles in photosynthesis, photoprotection, and as precursors to apocarotenoids. The plastidlocalized carotenoid biosynthetic pathway is mediated by well-defined nucleus-encoded enzymes. However, there is a major gap in understanding the nature of protein interactions and pathway complexes needed to mediate carotenogenesis. In this study, we focused on carotene ring hydroxylation, which is performed by two structurally distinct classes of enzymes, the P450 CYP97A and CYP97C hydroxylases and the nonheme diiron HYD enzymes. The CYP97A and HYD enzymes both function in the hydroxylation of β-rings in carotenes, but we show that they are not functionally interchangeable. The formation of lutein, which involves hydroxylation of both β-and ε -rings, was shown to require the coexpression of CYP97A and CYP97C enzymes. These enzymes were also demonstrated to interact in vivo and in vitro, as determined using bimolecular fluorescence complementation and a pull-down assay, respectively. We discuss the role of specific hydroxylase enzyme interactions in promoting pathway flux and preventing the formation of pathway dead ends. These findings will facilitate efforts to manipulate carotenoid content and composition for improving plant adaptation to climate change and/or for enhancing nutritionally important carotenoids in food crops.
AB - Plant carotenoids play essential roles in photosynthesis, photoprotection, and as precursors to apocarotenoids. The plastidlocalized carotenoid biosynthetic pathway is mediated by well-defined nucleus-encoded enzymes. However, there is a major gap in understanding the nature of protein interactions and pathway complexes needed to mediate carotenogenesis. In this study, we focused on carotene ring hydroxylation, which is performed by two structurally distinct classes of enzymes, the P450 CYP97A and CYP97C hydroxylases and the nonheme diiron HYD enzymes. The CYP97A and HYD enzymes both function in the hydroxylation of β-rings in carotenes, but we show that they are not functionally interchangeable. The formation of lutein, which involves hydroxylation of both β-and ε -rings, was shown to require the coexpression of CYP97A and CYP97C enzymes. These enzymes were also demonstrated to interact in vivo and in vitro, as determined using bimolecular fluorescence complementation and a pull-down assay, respectively. We discuss the role of specific hydroxylase enzyme interactions in promoting pathway flux and preventing the formation of pathway dead ends. These findings will facilitate efforts to manipulate carotenoid content and composition for improving plant adaptation to climate change and/or for enhancing nutritionally important carotenoids in food crops.
UR - http://www.scopus.com/inward/record.url?scp=84865857132&partnerID=8YFLogxK
U2 - 10.1104/pp.112.198556
DO - 10.1104/pp.112.198556
M3 - Article
C2 - 22786888
AN - SCOPUS:84865857132
SN - 0032-0889
VL - 160
SP - 204
EP - 214
JO - Plant Physiology
JF - Plant Physiology
IS - 1
ER -