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GO:0009976

Overview

Field Value
Namespace Molecular function
Short description Tocopherol cyclase activity
Full defintion Catalysis of the reaction: alkene group + alcohol group on same molecule = cyclic ether. Substrates are 2-methyl-6-phytyl-1,4- hydroquinone (forms delta-tocopherol) and 2,3-dimethyl-5-phytyl-1,4-hydroquinone (forms gamma-tocopherol).
Subterm of

Relationships

The relationship of GO:0009976 with other GO terms.

Relationship type GO terms
Is a
Regulates n.a.
Part of n.a.
Positively regulates n.a.
Negatively regulates n.a.

Ancestor tree

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Additional data

This table contains additional metadata associated with the GO entry's definition field.

Field Value
PMID
Isolation of an Arabidopsis mutant lacking vitamin E and identification of a cyclase essential for all tocopherol biosynthesis.
Proc Natl Acad Sci U S A. ; 99 (19): 12495–500.PMID: 12213958

Tocopherol (vitamin E) is a plant chloroplast lipid presumed to be involved in the response to oxidative stress. A tocopherol-deficient mutant (vte1) was isolated from Arabidopsis thaliana by using a TLC-based screening approach. Mutant plants lacked all four tocopherol forms and were deficient in tocopherol cyclase activity. Genetic mapping of vte1 and a genomics-based approach led to the identification of the ORF At4g32770 as a candidate gene for tocopherol cyclase. In vte1, At4g32770 contains a splicing site mutation and the corresponding mRNA expression is reduced. Expression of VTE1 in Escherichia coli resulted in the production of a protein with high tocopherol cyclase and tocotrienol cyclase activity. The VTE1 sequence shows no similarities to genes with known function, but is similar to that of SXD1, a gene that was recently isolated based on the availability of the sucrose export defective1 maize mutant (sxd1). Growth of the vte1 mutant, chlorophyll content, and photosynthetic quantum yield were similar to wild type under optimal growth conditions. Therefore, absence of tocopherol has no large impact on photosynthesis or plant viability, suggesting that other antioxidants can compensate for the loss of tocopherol. During photo-oxidative stress, chlorophyll content and photosynthetic quantum yield were slightly reduced in vte1 as compared with wild type indicating a potential role for tocopherol in maintaining an optimal photosynthesis rate under high-light stress.

Associated Lotus transcripts 12

GO predictions are based solely on the InterPro-to-GO mappings published by EMBL-EBI, which are in turn based on the mapping of predicted domains to the InterPro dataset. The InterPro-to-GO mapping was last updated on , while the GO metadata was last updated on .

Transcript Name Description GO terms GO count
PREDICTED: tocopherol cyclase, chloroplastic-like [Glycine max] gi|356507907|ref|XP_003522704.1| 1
Tocopherol cyclase [Phaseolus vulgaris] gi|188484539|gb|ACD50891.1| 1
Tocopherol cyclase [Medicago truncatula] gi|358344734|ref|XP_003636442.1| 1
Tocopherol cyclase; TAIR: AT4G32770.1 tocopherol cyclase, chloroplast / vitamin E deficient 1 (VTE1) / sucrose export defective 1 (SXD1); Swiss-Prot: sp|Q94FY7|TOCC_ARATH Tocopherol cyclase, chloroplastic; TrEMBL-Plants: tr|I3SJK8|I3SJK8_LOTJA Uncharacterized protein; Found in the gene: LotjaGi1g1v0402100_LC 1
Tocopherol cyclase; TAIR: AT4G32770.1 tocopherol cyclase, chloroplast / vitamin E deficient 1 (VTE1) / sucrose export defective 1 (SXD1); Swiss-Prot: sp|Q94FY7|TOCC_ARATH Tocopherol cyclase, chloroplastic; TrEMBL-Plants: tr|A0A072V2G5|A0A072V2G5_MEDTR Tocopherol cyclase; Found in the gene: LotjaGi1g1v0402300 1
Tocopherol cyclase; TAIR: AT4G32770.1 tocopherol cyclase, chloroplast / vitamin E deficient 1 (VTE1) / sucrose export defective 1 (SXD1); Swiss-Prot: sp|Q94FY7|TOCC_ARATH Tocopherol cyclase, chloroplastic; TrEMBL-Plants: tr|A0A072V2G5|A0A072V2G5_MEDTR Tocopherol cyclase; Found in the gene: LotjaGi1g1v0402300 1
Tocopherol cyclase; TAIR: AT4G32770.1 tocopherol cyclase, chloroplast / vitamin E deficient 1 (VTE1) / sucrose export defective 1 (SXD1); Swiss-Prot: sp|Q94FY7|TOCC_ARATH Tocopherol cyclase, chloroplastic; TrEMBL-Plants: tr|I3SAG4|I3SAG4_LOTJA Uncharacterized protein; Found in the gene: LotjaGi1g1v0402600_LC 1
Tocopherol cyclase; TAIR: AT4G32770.1 tocopherol cyclase, chloroplast / vitamin E deficient 1 (VTE1) / sucrose export defective 1 (SXD1); Swiss-Prot: sp|Q94FY7|TOCC_ARATH Tocopherol cyclase, chloroplastic; TrEMBL-Plants: tr|A0A072V2G5|A0A072V2G5_MEDTR Tocopherol cyclase; Found in the gene: LotjaGi1g1v0402900 1
Tocopherol cyclase; TAIR: AT4G32770.1 tocopherol cyclase, chloroplast / vitamin E deficient 1 (VTE1) / sucrose export defective 1 (SXD1); Swiss-Prot: sp|Q94FY7|TOCC_ARATH Tocopherol cyclase, chloroplastic; TrEMBL-Plants: tr|A0A072V2G5|A0A072V2G5_MEDTR Tocopherol cyclase; Found in the gene: LotjaGi1g1v0403300 1
Tocopherol cyclase; TAIR: AT4G32770.1 tocopherol cyclase, chloroplast / vitamin E deficient 1 (VTE1) / sucrose export defective 1 (SXD1); Swiss-Prot: sp|Q94FY7|TOCC_ARATH Tocopherol cyclase, chloroplastic; TrEMBL-Plants: tr|A0A072V2G5|A0A072V2G5_MEDTR Tocopherol cyclase; Found in the gene: LotjaGi1g1v0403600 1
Tocopherol cyclase; TAIR: AT4G32770.1 tocopherol cyclase, chloroplast / vitamin E deficient 1 (VTE1) / sucrose export defective 1 (SXD1); Swiss-Prot: sp|Q94FY7|TOCC_ARATH Tocopherol cyclase, chloroplastic; TrEMBL-Plants: tr|A0A072V2G5|A0A072V2G5_MEDTR Tocopherol cyclase; Found in the gene: LotjaGi1g1v0403600 1
Tocopherol cyclase; TAIR: AT4G32770.1 tocopherol cyclase, chloroplast / vitamin E deficient 1 (VTE1) / sucrose export defective 1 (SXD1); Swiss-Prot: sp|Q94FY7|TOCC_ARATH Tocopherol cyclase, chloroplastic; TrEMBL-Plants: tr|I3SAG4|I3SAG4_LOTJA Uncharacterized protein; Found in the gene: LotjaGi1g1v0407800_LC 1

Co-occuring GO terms 1

A list of co-occurring GO terms within the L. japonicus gene space:

GO term Namespace Name Observations Saturation (%)
Molecular function Tocopherol cyclase activity 1 8.33