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Q8GCH2 (GUMK2_XANCP) Reviewed, UniProtKB/Swiss-Prot

Last modified January 25, 2012. Version 22. Feed History...

Clusters with 100%, 90%, 50% identity | Documents (3) | Third-party data text xml rdf/xml gff fasta
to top of pageNames·Attributes·General annotation·Ontologies·Sequence annotation·Sequences·References·Cross-refs·Entry info·DocumentsCustomize order

Names and origin

Protein namesRecommended name:
UDP-glucuronate:glycolipid 2-beta-glucuronosyltransferase

Short name=UDP-GlcA:glycolipid glucuronosyltransferase
EC=2.4.1.264
Alternative name(s):
D-man-alpha-(1->3)-D-Glc-beta-(1->4)-D-Glc-alpha-1-diphosphoundecaprenol 2-beta-glucuronyltransferase
Gene names
Name:gumK
OrganismXanthomonas campestris pv. campestris
Taxonomic identifier340 [NCBI]
Taxonomic lineageBacteriaProteobacteriaGammaproteobacteriaXanthomonadalesXanthomonadaceaeXanthomonas

Protein attributes

Sequence length400 AA.
Sequence statusComplete.
Protein existenceEvidence at protein level

General annotation (Comments)

Function

Catalyzes the transfer of a glucuronic acid (GlcA) residue from UDP-glucuronate to mannose-alpha-1,3-glucose-beta-1,4-glucose-P-P-polyisoprenyl to form the lipid-linked tetrasaccharide GlcA-Man-Glc(2)-PP-Pol, with a glucuronic acid-beta-mannose linkage. Is involved in the biosynthesis of the exopolysaccharide xanthan, since it catalyzes the fourth glycosylation step in the assembly of the pentasaccharide-P-P-polyisoprenyl repeating unit of xanthan. Is unable to use the trisaccharide acceptor freed from the pyrophosphate lipid moiety. Does not show specificity for the lipidic portion of the acceptor. Shows diminished activity when tested with 6-O-acetyl-mannose-alpha-1,3-glucose-beta-1,4-glucose-P-P-polyisoprenyl, a putative intermediate in the synthesis of xanthan; this could indicate that acetylation of the internal mannose takes place after the formation of the GumK product. Ref.2

Catalytic activity

UDP-glucuronate + D-Man-alpha-(1->3)-D-Glc-beta-(1->4)-D-Glc-alpha-1-diphospho-ditrans,octacis-undecaprenol = UDP + D-GlcA-beta-(1->2)-D-Man-alpha-(1->3)-D-Glc-beta-(1->4)-D-Glc-alpha-1-diphospho-ditrans,octacis-undecaprenol. Ref.2 Ref.5

Pathway

Glycan biosynthesis; xanthan biosynthesis. Ref.2

Subcellular location

Cell inner membrane; Peripheral membrane protein; Cytoplasmic side Ref.2.

Disruption phenotype

Cells lacking this gene accumulate Man-alpha-1,3-Glc-beta-1,4-Glc-PP-polyisoprenyl, are unable to produce GlcA-Man-Glc(2)-PP-Pol, and show a decrease in xanthan production of more than 95%. Ref.2 Ref.3

Sequence similarities

Belongs to the glycosyltransferase 70 family.

Biophysicochemical properties

Kinetic parameters:

KM=62 µM for UDP-glucuronate Ref.5

KM=198 µM for Man-Glc(2)-PP-Pol

Vmax=116 pmol/min/µg enzyme

Sequence caution

The sequence AAA86379.1 differs from that shown. Reason: Erroneous initiation. Translation N-terminally extended.

Ontologies

Keywords
   Biological processCarbohydrate metabolism
   Cellular componentCell inner membrane
Cell membrane
Membrane
   Molecular functionGlycosyltransferase
Transferase
   Technical term3D-structure
Gene Ontology (GO)
   Biological processpolysaccharide biosynthetic process

Inferred from mutant phenotype Ref.2. Source: UniProtKB

   Cellular componentplasma membrane

Inferred from direct assay Ref.2. Source: UniProtKB

   Molecular functionglucuronosyltransferase activity

Inferred from direct assay Ref.2. Source: UniProtKB

Complete GO annotation...

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Chain1 – 400400UDP-glucuronate:glycolipid 2-beta-glucuronosyltransferase
PRO_0000414019

Regions

Region230 – 2312UDP-glucuronate binding
Region272 – 2732UDP-glucuronate binding
Region306 – 3105UDP-glucuronate binding

Sites

Active site1571Proton acceptor Ref.5
Binding site2921UDP-glucuronate

Experimental info

Mutagenesis1571D → A, E or N: Loss of catalytic activity. Loss of xanthan production. Ref.5
Mutagenesis1921E → A: No effect on both substrate affinity and catalytic activity. Ref.5
Mutagenesis2071D → A: No effect on both substrate affinity and catalytic activity. Ref.5
Mutagenesis2311M → A: No effect on both substrate affinity and catalytic activity. Ref.5
Mutagenesis2341D → A: No effect on both substrate affinity and catalytic activity. Ref.5
Mutagenesis2721E → A: 2-fold decrease in both affinity for UDP-GlcA and catalytic activity. Ref.5
Mutagenesis2921Y → A: 14-fold decrease in catalytic efficiency. 25% of wild-type xanthan production. Ref.5
Mutagenesis3071K → A: 54-fold decrease in catalytic efficiency. 30% of wild-type xanthan production. Ref.5
Mutagenesis3101Q → A: 19-fold decrease in affinity for UDP-GlcA but no effect on catalytic activity. 60% of wild-type xanthan production. Ref.5
Sequence conflict21S → G in AAN86640. Ref.2
Sequence conflict21S → G in AAA86379. Ref.2
Sequence conflict221A → S in AAN86640. Ref.2
Sequence conflict221A → S in AAA86379. Ref.2
Sequence conflict1941A → V in AAN86640. Ref.2
Sequence conflict1941A → V in AAA86379. Ref.2

Secondary structure

........................................................................ 400
Helix Strand Turn

Details...

Sequences

Sequence LengthMass (Da)Tools
Q8GCH2 [UniParc].

Last modified November 16, 2011. Version 2.
Checksum: 250231946AB7EB61

FASTA40044,438
        10         20         30         40         50         60 
MSVSPAAPAS GIRRPCYLVL SAHDFRTPRR ANIHFITDQL ALRGTTRFFS LRYSRLSRMK 

        70         80         90        100        110        120 
GDMRLPLDDT ANTVVSHNGV DCYLWRTTVH PFNTRRSWLR PVEDAMFRWY AAHPPKQLLD 

       130        140        150        160        170        180 
WMRESDVIVF ESGIAVAFIE LAKRVNPAAK LVYRASDGLS TINVASYIER EFDRVAPTLD 

       190        200        210        220        230        240 
VIALVSPAMA AEVASRDNVF HVGHGVDHNL DQLGDPSPYA EGIHAVAVGS MLFDPEFFVV 

       250        260        270        280        290        300 
ASKAFPQVTF HVIGSGMGRH PGYGDNVIVY GEMKHAQTIG YIKHARFGIA PYASEQVPVY 

       310        320        330        340        350        360 
LADSSMKLLQ YDFFGLPAVC PNAVVGPYKS RFGYTPGNAD SVIAAITQAL EAPRVRYRQC 

       370        380        390        400 
LNWSDTTDRV LDPRAYPETR LYPHPPTAAP QLSSEAALSH 

« Hide

References

[1]"Recombinant-DNA mediated production of xanthan gum."
Capage M.A., Doherty D.H., Betlach M.R., Vanderslice R.W.
Submitted (APR-1995) to the EMBL/GenBank/DDBJ databases
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
Strain: ATCC 13951 / NCIB 11803 / NRRL B-1459.
[2]"Functional characterization of GumK, a membrane-associated beta-glucuronosyltransferase from Xanthomonas campestris required for xanthan polysaccharide synthesis."
Barreras M., Abdian P.L., Ielpi L.
Glycobiology 14:233-241(2004) [PubMed: 14736729] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA], IDENTIFICATION OF START SITE, FUNCTION, CATALYTIC ACTIVITY, ROLE IN XANTHAN BIOSYNTHESIS, SUBSTRATE SPECIFICITY, SUBCELLULAR LOCATION, DISRUPTION PHENOTYPE, PATHWAY.
Strain: ATCC 13951 / NCIB 11803 / NRRL B-1459.
[3]"Xanthomonas campestris pv. campestris gum mutants: effects on xanthan biosynthesis and plant virulence."
Katzen F., Ferreiro D.U., Oddo C.G., Ielmini M.V., Becker A., Puhler A., Ielpi L.
J. Bacteriol. 180:1607-1617(1998) [PubMed: 9537354] [Abstract]
Cited for: DISRUPTION PHENOTYPE.
Strain: ATCC 13951 / NCIB 11803 / NRRL B-1459.
[4]"Crystallization and preliminary crystallographic characterization of GumK, a membrane-associated glucuronosyltransferase from Xanthomonas campestris required for xanthan polysaccharide synthesis."
Barreras M., Bianchet M.A., Ielpi L.
Acta Crystallogr. F 62:880-883(2006) [PubMed: 16946469] [Abstract]
Cited for: CRYSTALLIZATION.
Strain: ATCC 13951 / NCIB 11803 / NRRL B-1459.
[5]"Structure and mechanism of GumK, a membrane-associated glucuronosyltransferase."
Barreras M., Salinas S.R., Abdian P.L., Kampel M.A., Ielpi L.
J. Biol. Chem. 283:25027-25035(2008) [PubMed: 18596046] [Abstract]
Cited for: X-RAY CRYSTALLOGRAPHY (1.90 ANGSTROMS) OF WILD-TYPE AND MUTANT ALA-157 APOENZYME AND IN COMPLEX WITH UDP, CATALYTIC ACTIVITY, KINETIC PARAMETERS, MUTAGENESIS OF ASP-157; GLU-192; ASP-207; MET-231; ASP-234; GLU-272; TYR-292; LYS-307 AND GLN-310, ACTIVE SITE, CATALYTIC MECHANISM.
Strain: ATCC 13951 / NCIB 11803 / NRRL B-1459.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ
U22511 Genomic DNA. Translation: AAA86379.1. Different initiation.
AY170889 Genomic DNA. Translation: AAN86640.1.
PIRS67860.

3D structure databases

PDBe
RCSB PDB
PDBj
EntryMethodResolution (Å)ChainPositionsPDBsum
2HY7X-ray1.90A1-400[»]
2Q6VX-ray2.28A1-400[»]
3CUYX-ray2.30A1-400[»]
3CV3X-ray2.25A1-400[»]
ProteinModelPortalQ8GCH2.
ModBaseSearch...

Protein family/group databases

CAZyGT70. Glycosyltransferase Family 70.

Protocols and materials databases

StructuralBiologyKnowledgebaseSearch...

Family and domain databases

ProtoNetSearch...

Entry information

Entry nameGUMK2_XANCP
AccessionPrimary (citable) accession number: Q8GCH2
Secondary accession number(s): Q56777
Entry history
Integrated into UniProtKB/Swiss-Prot: November 16, 2011
Last sequence update: November 16, 2011
Last modified: January 25, 2012
This is version 22 of the entry and version 2 of the sequence. [Complete history]
Entry statusReviewed (UniProtKB/Swiss-Prot)
Annotation programProkaryotic Protein Annotation Program

Relevant documents

PATHWAY comments

Index of metabolic and biosynthesis pathways

PDB cross-references

Index of Protein Data Bank (PDB) cross-references

SIMILARITY comments

Index of protein domains and families