title: Control of carotenoid biosynthesis through a heme-based cis-trans isomerase.
abstract: 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.
authors.affiliation: 1] Department of Biological Sciences, Lehman College, City University of New York (CUNY), Bronx, New York, USA. [2] Graduate School and University Center, CUNY, New York, New York, USA.
authors.forename: Jesús
authors.identifier: 0000000188043125
authors.initials: J
authors.lastname: Beltrán
authors.affiliation: New York Structural Biology Center, New York, New York, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Kloss
authors.affiliation: Department of Biochemistry, University of Mississippi Medical Center, Jackson, Mississippi, USA.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Hosler
authors.affiliation: Department of Chemistry, Georgia State University, Atlanta, Georgia, USA.
authors.forename: Jiafeng
authors.initials: J
authors.lastname: Geng
authors.affiliation: Department of Chemistry, Georgia State University, Atlanta, Georgia, USA.
authors.forename: Aimin
authors.identifier: 0000000241828176
authors.initials: A
authors.lastname: Liu
authors.affiliation: Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina, USA.
authors.forename: Anuja
authors.initials: A
authors.lastname: Modi
authors.affiliation: Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina, USA.
authors.forename: John H
authors.initials: JH
authors.lastname: Dawson
authors.affiliation: Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina, USA.
authors.forename: Masanori
authors.initials: M
authors.lastname: Sono
authors.affiliation: Department of Biological Sciences, Lehman College, City University of New York (CUNY), Bronx, New York, USA.
authors.forename: Maria
authors.initials: M
authors.lastname: Shumskaya
authors.affiliation: Department of Biological Sciences, Lehman College, City University of New York (CUNY), Bronx, New York, USA.
authors.forename: Charles
authors.initials: C
authors.lastname: Ampomah-Dwamena
authors.affiliation: New York Structural Biology Center, New York, New York, USA.
authors.forename: James D
authors.initials: JD
authors.lastname: Love
authors.affiliation: 1] Department of Biological Sciences, Lehman College, City University of New York (CUNY), Bronx, New York, USA. [2] Graduate School and University Center, CUNY, New York, New York, USA.
authors.forename: Eleanore T
authors.initials: ET
authors.lastname: Wurtzel
mesh_terms: D017360:Arabidopsis / Q000737:chemistry / Q000201:enzymology; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002736:Chloroplasts / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006418:Heme / Q000737:chemistry / Q000378:metabolism*; D057927:Hydrophobic and Hydrophilic Interactions; D007501:Iron / Q000737:chemistry / Q000378:metabolism*; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D007536:Isomerism; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D010084:Oxidation-Reduction; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D003313:Zea mays / Q000737:chemistry* / Q000201:enzymology / Q000235:genetics; D019745:cis-trans-Isomerases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D024321:zeta Carotene / Q000096:biosynthesis*
chemical_list: D029681:Arabidopsis Proteins; D007527:Isoenzymes; D008565:Membrane Proteins; D010940:Plant Proteins; D011994:Recombinant Proteins; D024321:zeta Carotene; D006418:Heme; D007501:Iron; C551457:15-cis-zeta-carotene isomerase, Arabidopsis; D019745:cis-trans-Isomerases