Gene/Proteome Database (LMPD)

LMPD ID
LMP010239
Gene ID
828792
Species
Arabidopsis thaliana (Arabidopsis)
Gene Name
GDP-L-galactose phosphorylase 1
Gene Symbol
VTC2
Synonyms
F10M23.190; F10M23_190; vitamin c defective 2; VTC2
Alternate Names
GDP-L-galactose phosphorylase 1
Chromosome
4
EC Number
2.7.7.69
Summary
Encodes a novel protein involved in ascorbate biosynthesis, which was shown to catalyze the transfer of GMP from GDP-galactose to a variety of hexose-1-phosphate acceptors. Recessive mutation has a reduced amount of vitamin C, lower level of non-photochemical quenching, and reduced rate of conversion of violaxanthin to zeaxanthin in high light.
Orthologs
View orthologs and multiple alignments for VTC2

Proteins

GDP-L-galactose phosphorylase 1
Refseq ID NP_567759
Protein GI 18416877
UniProt ID Q8RWE8
mRNA ID NM_118819
Length 442
RefSeq Status REVIEWED
MLKIKRVPTVVSNYQKDDGAEDPVGCGRNCLGACCLNGARLPLYACKNLVKSGEKLVISHEAIEPPVAFLESLVLGEWEDRFQRGLFRYDVTACETKVIPGKYGFVAQLNEGRHLKKRPTEFRVDKVLQSFDGSKFNFTKVGQEELLFQFEAGEDAQVQFFPCMPIDPENSPSVVAINVSPIEYGHVLLIPRVLDCLPQRIDHKSLLLAVHMAAEAANPYFRLGYNSLGAFATINHLHFQAYYLAMPFPLEKAPTKKITTTVSGVKISELLSYPVRSLLFEGGSSMQELSDTVSDCCVCLQNNNIPFNILISDCGRQIFLMPQCYAEKQALGEVSPEVLETQVNPAVWEISGHMVLKRKEDYEGASEDNAWRLLAEASLSEERFKEVTALAFEAIGCSNQEEDLEGTIVHQQNSSGNVNQKSNRTHGGPITNGTAAECLVLQ

Gene Information

Entrez Gene ID
828792
Gene Name
GDP-L-galactose phosphorylase 1
Gene Symbol
VTC2
Species
Arabidopsis thaliana

Gene Ontology (GO Annotations)

GO ID Source Type Description
GO:0005737 IEA:UniProtKB-KW C cytoplasm
GO:0005634 IEA:UniProtKB-KW C nucleus
GO:0080048 IDA:TAIR F GDP-D-glucose phosphorylase activity
GO:0010472 IDA:TAIR F GDP-galactose:glucose-1-phosphate guanylyltransferase activity
GO:0010471 IDA:TAIR F GDP-galactose:mannose-1-phosphate guanylyltransferase activity
GO:0010473 IDA:TAIR F GDP-galactose:myoinositol-1-phosphate guanylyltransferase activity
GO:0010475 IDA:TAIR F galactose-1-phosphate guanylyltransferase (GDP) activity
GO:0010474 IDA:TAIR F glucose-1-phosphate guanylyltransferase (GDP) activity
GO:0005085 IEA:UniProtKB-KW F guanyl-nucleotide exchange factor activity
GO:0016787 IEA:UniProtKB-KW F hydrolase activity
GO:0008928 IDA:TAIR F mannose-1-phosphate guanylyltransferase (GDP) activity
GO:0000166 IEA:UniProtKB-KW F nucleotide binding
GO:0080046 IDA:TAIR F quercetin 4'-O-glucosyltransferase activity
GO:0019853 IMP:TAIR P L-ascorbic acid biosynthetic process
GO:0052544 IMP:TAIR P defense response by callose deposition in cell wall
GO:0042742 IMP:TAIR P defense response to bacterium
GO:0009408 IMP:TAIR P response to heat
GO:0009753 IEP:TAIR P response to jasmonic acid

KEGG Pathway Links

KEGG Pathway ID Description
ath00053 Ascorbate and aldarate metabolism
ath_M00114 Ascorbate biosynthesis, plants, glucose-6P => ascorbate
ath01110 Biosynthesis of secondary metabolites
ath01100 Metabolic pathways

Domain Information

InterPro Annotations

Accession Description
IPR026506 GDP-L-galactose/GDP-D-glucose phosphorylase

UniProt Annotations

Entry Information

Gene Name
GDP-L-galactose phosphorylase 1
Protein Entry
GGAP1_ARATH
UniProt ID
Q8RWE8
Species
Arabidopsis

Comments

Comment Type Description
Biophysicochemical Properties Kinetic parameters: KM=0.01 mM for GDP-L-galactose {ECO:0000269|PubMed:17462988, ECO:0000269|PubMed:17877701}; KM=0.0044 mM for GDP-D-glucose {ECO:0000269|PubMed:17462988, ECO:0000269|PubMed:17877701}; KM=0.52 mM for GDP-D-mannose {ECO:0000269|PubMed:17462988, ECO:0000269|PubMed:17877701}; KM=2.4 mM for phosphate {ECO:0000269|PubMed:17462988, ECO:0000269|PubMed:17877701}; KM=0.76 mM for phosphate {ECO:0000269|PubMed:17462988, ECO:0000269|PubMed:17877701}; KM=45 mM for L-galactose 1-phosphate {ECO:0000269|PubMed:17462988, ECO:0000269|PubMed:17877701}; KM=29 mM for D-glucose 1-phosphate {ECO:0000269|PubMed:17462988, ECO:0000269|PubMed:17877701}; KM=54 mM for D-mannose 1-phosphate {ECO:0000269|PubMed:17462988, ECO:0000269|PubMed:17877701}; KM=67 mM for D-galactose 1-phosphate {ECO:0000269|PubMed:17462988, ECO:0000269|PubMed:17877701}; Note=The kinetic properties described in PubMed:17877701 differ quite substantially from the ones shown here. This might be due to the use of different enzyme activity assays.; pH dependence: Optimum pH is 7.5. {ECO:0000269|PubMed:17462988, ECO:0000269|PubMed:17877701};
Catalytic Activity GDP-L-galactose + phosphate = alpha-L- galactose 1-phosphate + GDP. {ECO:0000269|PubMed:17462988, ECO:0000269|PubMed:17485667, ECO:0000269|PubMed:17877701}.
Caution According to publications, it is related to the galactose-1-phosphate uridylyltransferase type 1 family and histidine triad superfamily (PubMed:12119013). However, such families are not detected by prediction tools such as Pfam or SUPFAM. {ECO:0000305|PubMed:12119013}.
Developmental Stage Expressed in all developmental stages. {ECO:0000269|PubMed:18516687}.
Disruption Phenotype Dwarf. 20% of the wild-type ascorbate level, due to the partial redundancy with VTC5. Vtc2 and vtc5 double mutants show growth arrest immediately upon germination and are not viable. {ECO:0000269|PubMed:17877701}.
Enzyme Regulation Not inhibited by dithiothreitol, N- ethylmaleimide, phenylmethane sulfonyl fluoride, ascorbate, L- galactose and L-galactonolactone.
Function Catalyzes a reaction of the Smirnoff-Wheeler pathway, the major route to ascorbate biosynthesis in plants. Acts as a phosphorylase rather than as a transferase. Uses preferentially GDP-L-galactose and GDP-D-glucose as substrates. Lower activity with GDP-L-fucose, very low activity with GDP-D-mannose, and no activity with UDP-D-glucose, UDP-D-galactose or ADP-D-glucose. Highly specific for inorganic phosphate as the guanylyl acceptor. {ECO:0000269|PubMed:17462988, ECO:0000269|PubMed:17485667, ECO:0000269|PubMed:17877701, ECO:0000269|PubMed:18463094}.
Induction By jasmonate, ozone and high light. Circadian- regulation, with a peak in expression at the beginning of the light cycle. {ECO:0000269|PubMed:16262714, ECO:0000269|PubMed:17877701, ECO:0000269|PubMed:18516687}.
Interaction O64511-2:TLP1; NbExp=2; IntAct=EBI-1578760, EBI-1578748;
Pathway Cofactor biosynthesis; L-ascorbate biosynthesis via GDP- alpha-D-mannose pathway; L-ascorbate from GDP-alpha-D-mannose: step 2/5.
Sequence Caution Sequence=AAM34266.1; Type=Erroneous gene model prediction; Evidence={ECO:0000305}; Sequence=CAB36531.1; Type=Erroneous gene model prediction; Evidence={ECO:0000305}; Sequence=CAB79540.1; Type=Erroneous gene model prediction; Evidence={ECO:0000305};
Similarity Belongs to the GDPGP1 family. {ECO:0000305}.
Subcellular Location Cytoplasm {ECO:0000269|PubMed:18516687}. Nucleus {ECO:0000269|PubMed:18516687}.
Subunit Interacts with TLP1. {ECO:0000269|PubMed:17982713}.
Tissue Specificity Expressed in leaves, stems, roots, flowers and siliques. Highest expression in green tissues. {ECO:0000269|PubMed:17877701, ECO:0000269|PubMed:18516687}.

Identical and Related Proteins

Unique RefSeq proteins for LMP010239 (as displayed in Record Overview)

Protein GI Database Accession Length Protein Name
18416877 RefSeq NP_567759 442 GDP-L-galactose phosphorylase 1

Identical Sequences to LMP010239 proteins

Reference Database Accession Length Protein Name
GI:18416877 DBBJ BAE98540.1 442 hypothetical protein [Arabidopsis thaliana]
GI:18416877 GenBank ADT60811.1 442 Sequence 2512 from patent US 7847156
GI:18416877 GenBank AEE85260.1 442 GDP-L-galactose phosphorylase 1 [Arabidopsis thaliana]
GI:18416877 GenBank AFX48756.1 442 Sequence 50589 from patent US 8299318
GI:18416877 GenBank AGD22609.1 442 Sequence 20065 from patent US 8343764
GI:18416877 GenBank AGF15267.1 442 Sequence 14686 from patent US 8362325

Related Sequences to LMP010239 proteins

Reference Database Accession Length Protein Name
GI:18416877 EMBL CAB36531.1 459 putative protein [Arabidopsis thaliana]
GI:18416877 EMBL CAB79540.1 459 putative protein [Arabidopsis thaliana]
GI:18416877 GenBank AAL07213.1 442 unknown protein [Arabidopsis thaliana]
GI:18416877 GenBank AAM34266.1 459 VTC2 [Arabidopsis thaliana]
GI:18416877 GenBank EFH43797.1 444 hypothetical protein ARALYDRAFT_492115 [Arabidopsis lyrata subsp. lyrata]
GI:18416877 GenBank AGD15027.1 442 Sequence 12483 from patent US 8343764