Q09LX1 · AXE2_GEOSE
- ProteinAcetylxylan esterase
- Geneaxe2
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids219 (go to sequence)
- Protein existenceEvidence at protein level
- Annotation score5/5
Function
function
Acetylxylan esterase involved in the degradation of xylan, a major structural heterogeneous polysaccharide found in plant biomass representing the second most abundant polysaccharide in the biosphere, after cellulose. Cleaves acetyl side groups from the xylose backbone units of the hemicellulolytic polymer xylan and xylo-oligosaccharides. Hydrolyzes about 20%-30% of the available acetyl groups on fully acetylated birch wood xylan. Completely deacetylates xylobiose peracetate (fully acetylated), and is active on both the alpha- and beta-forms of the sugar. Also hydrolyzes fully acetylated methyl-beta-D-xylopyranoside and methyl-beta-D-glucopyranoside, and the synthetic substrates 2-naphthyl acetate, 4-nitrophenyl acetate, 4-methylumbelliferyl acetate, and phenyl acetate.
Catalytic activity
Kinetics
KM | SUBSTRATE | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|---|
7 mM | phenyl acetate | 6.0 | 30 | |||
9 mM | 2-naphtyl acetate | 6.0 | 30 | |||
3 mM | 4-methylumbelliferyl acetate | 6.0 | 30 | |||
27 mM | 4-nitrophenyl acetate | 6.0 | 30 |
kcat is 77 sec-1 with phenyl acetate as substrate. kcat is 190 sec-1 with 2-naphtyl acetate as substrate. kcat is 123 sec-1 with 4-methylumbelliferyl acetate as substrate. kcat is 31 sec-1 with 4-nitrophenyl acetate as substrate (at pH 6.0 and 30 degrees Celsius).
pH Dependence
Optimum pH is 7.1-9.2.
Temperature Dependence
Optimum temperature is 50-60 degrees Celsius. Is stable at 60 degrees Celsius and loses most of its activity at 70 degrees Celsius.
Pathway
Glycan degradation; xylan degradation.
Features
Showing features for active site, site.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Active site | 15 | Nucleophile | |||
Site | 63 | Transition state stabilizer | |||
Site | 92 | Transition state stabilizer | |||
Active site | 191 | Charge relay system | |||
Active site | 194 | Charge relay system | |||
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | cytoplasm | |
Molecular Function | acetylxylan esterase activity | |
Molecular Function | lysophospholipase activity | |
Biological Process | xylan catabolic process |
Keywords
- Molecular function
- Biological process
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended nameAcetylxylan esterase
- EC number
- Alternative names
Gene names
Organism names
- Strain
- Taxonomic lineageBacteria > Bacillota > Bacilli > Bacillales > Bacillaceae > Geobacillus
Accessions
- Primary accessionQ09LX1
Subcellular Location
Phenotypes & Variants
Features
Showing features for mutagenesis.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Mutagenesis | 15 | Loss of catalytic activity. | |||
Mutagenesis | 184 | Significant reduction in catalytic activity and modification of the quaternary structure as a homodimer; when associated with P-190. | |||
Mutagenesis | 190 | Significant reduction in catalytic activity and modification of the quaternary structure as a homodimer; when associated with F-184. | |||
Mutagenesis | 191 | Loss of catalytic activity. | |||
Mutagenesis | 194 | Loss of catalytic activity. | |||
PTM/Processing
Features
Showing features for chain.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Chain | PRO_0000434101 | 1-219 | Acetylxylan esterase | ||
Expression
Induction
Up-regulated by xylose.
Interaction
Subunit
Homooctamer, presenting a unique donut-shaped quaternary structure built of two staggered tetrameric rings. The eight active sites are organized in four closely situated pairs, which face the relatively wide internal cavity.
Structure
Sequence
- Sequence statusComplete
- Length219
- Mass (Da)24,772
- Last updated2006-10-17 v1
- ChecksumA3F18C97F5F69E32
Keywords
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
DQ868502 EMBL· GenBank· DDBJ | ABI49953.1 EMBL· GenBank· DDBJ | Genomic DNA |