Gene Ontology annotation through association of InterPro records with GO terms
Annotation inferences using phylogenetic trees
Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt
Electronic Gene Ontology annotations created by ARBA machine learning models
Functional analysis of the beta and epsilon lycopene cyclase enzymes of Arabidopsis reveals a mechanism for control of cyclic carotenoid formation.
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The Arabidopsis beta cyclase introduces a beta ring at both ends of the linear, symmetrical lycopene to form bicyclic beta-carotene, while the epsilon cyclase adds a single epsilon ring; both use lycopene as substrate.
"introduces a ring at both ends of lycopene to form the bicyclic"
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When the beta and epsilon cyclases act together they convert lycopene to alpha-carotene; lycopene cyclization is the key branch point of carotenoid biosynthesis.
"cyclases convert lycopene to alpha-carotene"
Lutein accumulation in the absence of zeaxanthin restores nonphotochemical quenching in the Arabidopsis thaliana npq1 mutant.
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The szl1 suppressor of npq1 carries a point mutation in the LCYB gene, and pigment analysis identifies LCYB as the major lycopene beta-cyclase that is not involved in neoxanthin synthesis.
"contains a point mutation in the lycopene beta-cyclase (LCYB) gene."
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szl1 npq1 plants have reduced beta,beta-xanthophylls (low violaxanthin, antheraxanthin and neoxanthin) and accumulate more lutein and alpha-carotene, showing that reduced LCYB activity shifts flux toward the beta,epsilon branch.
"have low levels of violaxanthin, antheraxanthin, and neoxanthin."
Transformation of beta-lycopene cyclase genes from Salicornia europaea and Arabidopsis conferred salt tolerance in Arabidopsis and tobacco.
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Overexpression of a beta-lycopene cyclase (including Arabidopsis AtLCY) increases carotenoid content and improves salt/oxidative-stress tolerance by lowering ROS and protecting photosynthesis; this is a downstream, gain-of-function consequence of increased carotenoid pools rather than a distinct molecular activity of LCYB.
"improved salt tolerance by increasing synthesis of"
UniProt entry Q38933 (LCYB_ARATH)
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LCYB catalyzes the double cyclization converting lycopene to beta-carotene (and neurosporene to beta-zeacarotene); catalytic activity is a carotenoid psi-end derivative = a carotenoid beta-end derivative, Rhea:55620, EC 5.5.1.19.
"Reaction=a carotenoid psi-end derivative = a carotenoid beta-end"
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LCYB is a plastid/chloroplast enzyme with an N-terminal transit peptide.
"SUBCELLULAR LOCATION: Plastid, chloroplast"
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LCYB functions in beta-carotene biosynthesis within carotenoid biosynthesis.
"Carotenoid biosynthesis; beta-carotene biosynthesis."