TY - JOUR
T1 - Control of carotenoid biosynthesis through a heme-based cis-trans isomerase
AU - Beltrán, Jesús
AU - Kloss, Brian
AU - Hosler, Jonathan P.
AU - Geng, Jiafeng
AU - Liu, Aimin
AU - Modi, Anuja
AU - Dawson, John H.
AU - Sono, Masanori
AU - Shumskaya, Maria
AU - Ampomah-Dwamena, Charles
AU - Love, James D.
AU - Wurtzel, Eleanore T.
N1 - Publisher Copyright:
© Nature America, Inc. All rights reserved.
PY - 2015/8/23
Y1 - 2015/8/23
N2 - Plants synthesize carotenoids, which are essential for plant development and survival. These metabolites also serve as essential nutrients for human health. The biosynthetic pathway for all plant carotenoids occurs in chloroplasts and other plastids and requires 15-cis-ζ-carotene isomerase (Z-ISO). It was not known whether Z-ISO catalyzes isomerization alone or in combination with other enzymes. Here we show that Z-ISO is a bona fide enzyme and integral membrane protein. Z-ISO independently catalyzes the cis-trans isomerization of the 15-15′ carbon-carbon double bond in 9,15,9′-cis-ζ-carotene to produce the substrate required by the subsequent biosynthetic-pathway enzyme. We discovered that isomerization depends upon a ferrous heme b cofactor that undergoes redox-regulated ligand switching between the heme iron and alternate Z-ISO amino acid residues. Heme b-dependent isomerization of a large hydrophobic compound in a membrane was previously undescribed. As an isomerase, Z-ISO represents a new prototype for heme b proteins and potentially uses a new chemical mechanism.
AB - Plants synthesize carotenoids, which are essential for plant development and survival. These metabolites also serve as essential nutrients for human health. The biosynthetic pathway for all plant carotenoids occurs in chloroplasts and other plastids and requires 15-cis-ζ-carotene isomerase (Z-ISO). It was not known whether Z-ISO catalyzes isomerization alone or in combination with other enzymes. Here we show that Z-ISO is a bona fide enzyme and integral membrane protein. Z-ISO independently catalyzes the cis-trans isomerization of the 15-15′ carbon-carbon double bond in 9,15,9′-cis-ζ-carotene to produce the substrate required by the subsequent biosynthetic-pathway enzyme. We discovered that isomerization depends upon a ferrous heme b cofactor that undergoes redox-regulated ligand switching between the heme iron and alternate Z-ISO amino acid residues. Heme b-dependent isomerization of a large hydrophobic compound in a membrane was previously undescribed. As an isomerase, Z-ISO represents a new prototype for heme b proteins and potentially uses a new chemical mechanism.
UR - http://www.scopus.com/inward/record.url?scp=84937514111&partnerID=8YFLogxK
U2 - 10.1038/nchembio.1840
DO - 10.1038/nchembio.1840
M3 - Article
C2 - 26075523
AN - SCOPUS:84937514111
SN - 1552-4450
VL - 11
SP - 598
EP - 605
JO - Nature Chemical Biology
JF - Nature Chemical Biology
IS - 8
ER -