A0A2V0R8Q9 · LSCB_PSESF
- ProteinLevansucrase Lscbeta
- Genelscbeta
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids431 (go to sequence)
- Protein existenceEvidence at protein level
- Annotation score4/5
Function
function
Catalyzes the synthesis of levan, a fructose polymer, by transferring the fructosyl moiety from sucrose to a growing acceptor molecule (PubMed:33675829).
Also displays sucrose hydrolase activity (PubMed:33675829).
Also displays sucrose hydrolase activity (PubMed:33675829).
Miscellaneous
Strain KL103 contains two functional levansucrases, Lscbeta and Lscgamma (PubMed:33675829).
A third copy, lscalpha, is non-coding because of a premature stop codon (PubMed:33675829).
Lscbeta and Lscgamma show different sucrose splitting and polymerization properties, and differential expression, suggesting two distinct roles in the physiology of the bacterium (PubMed:33675829).
A third copy, lscalpha, is non-coding because of a premature stop codon (PubMed:33675829).
Lscbeta and Lscgamma show different sucrose splitting and polymerization properties, and differential expression, suggesting two distinct roles in the physiology of the bacterium (PubMed:33675829).
Catalytic activity
- [6)-beta-D-fructofuranosyl-(2->](n) alpha-D-glucopyranoside + sucrose = [6)-beta-D-fructofuranosyl-(2->](n+1) alpha-D-glucopyranoside + D-glucose
[6)-β-D-fructofuranosyl-(2→](n) α-D-glucopyranoside RHEA-COMP:13093 + CHEBI:17992 = [6)-β-D-fructofuranosyl-(2→](n+1) α-D-glucopyranoside RHEA-COMP:13094 + CHEBI:4167
Activity regulation
Sucrose hydrolase activity is negatively affected by salt concentration (PubMed:33675829).
The levan polymerization rate is constant regardless of sucrose concentration (PubMed:33675829).
The levan polymerization rate is constant regardless of sucrose concentration (PubMed:33675829).
Kinetics
KM | SUBSTRATE | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|---|
54.1 mM | sucrose | 5.0 | ||||
100.1 mM | sucrose | 7.0 |
kcat is 8500 min-1 with sucrose as substrate (at pH 5.0). kcat is 15000 min-1 with sucrose as substrate (at pH 7.0).
pH Dependence
For sucrose hydrolase activity, shows the maximal activity in the 5-7 pH range, while the activity decreases at pH values lower that 5 and higher than 8 (PubMed:33675829).
Levan polymerization occurs mainly at pH 5.0 (PubMed:33675829).
Levan polymerization occurs mainly at pH 5.0 (PubMed:33675829).
Temperature Dependence
Highly thermostable (PubMed:33675829).
At pH 5.0, sucrose hydrolase activity progressively increases with temperature until 55 degrees Celsius and then falls quickly (PubMed:33675829).
At ph 7.0, the sucrose hydrolase activity increases rapidly passing from 4 to 15 degrees Celsius and remains constant up to 55 degrees Celsius (PubMed:33675829).
At pH 5.0, sucrose hydrolase activity progressively increases with temperature until 55 degrees Celsius and then falls quickly (PubMed:33675829).
At ph 7.0, the sucrose hydrolase activity increases rapidly passing from 4 to 15 degrees Celsius and remains constant up to 55 degrees Celsius (PubMed:33675829).
Features
Showing features for binding site, active site, site.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Binding site | 61 | sucrose (UniProtKB | ChEBI) | ||||
Sequence: W | ||||||
Active site | 62 | Nucleophile | ||||
Sequence: D | ||||||
Binding site | 62 | sucrose (UniProtKB | ChEBI) | ||||
Sequence: D | ||||||
Binding site | 148 | sucrose (UniProtKB | ChEBI) | ||||
Sequence: A | ||||||
Binding site | 218 | sucrose (UniProtKB | ChEBI) | ||||
Sequence: R | ||||||
Binding site | 219 | sucrose (UniProtKB | ChEBI) | ||||
Sequence: D | ||||||
Site | 219 | Transition state stabilizer | ||||
Sequence: D | ||||||
Active site | 303 | Proton donor/acceptor | ||||
Sequence: E |
GO annotations
Aspect | Term | |
---|---|---|
Molecular Function | levansucrase activity | |
Biological Process | carbohydrate utilization |
Keywords
- Molecular function
- Biological process
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended nameLevansucrase Lscbeta
- EC number
- Alternative names
Gene names
Organism names
- Strain
- Taxonomic lineageBacteria > Pseudomonadota > Gammaproteobacteria > Pseudomonadales > Pseudomonadaceae > Pseudomonas > Pseudomonas syringae
Accessions
- Primary accessionA0A2V0R8Q9
Proteomes
PTM/Processing
Features
Showing features for chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Chain | PRO_0000459748 | 1-431 | Levansucrase Lscbeta | |||
Sequence: MSTSSSALSQLKNSPLAGNINYEPTVWSRADALKVNENDPTTTQPLVSADFPVMSDTVFIWDTMPLRELDGTVVSVNGWSVILTLTADRHPDDPQYLDANGRYDIKRDWEDRHGRARMCYWYSRTGKDWIFGGRVMAEGVSPTTREWAGTPILLNDKGDIDLYYTCVTPGAAIAKVRGRIVTSDQGVELKDFTQVKKLFEADGTYYQTEAQNSSWNFRDPSPFIDPNDGKLYMVFEGNVAGERGSHTVGAAELGPVPPGHEDVGGARFQVGCIGLAVAKDLSGEEWEILPPLVTAVGVNDQTERPHYIFQDGKYYLFTISHKFTYAEGLEGPDGVYGFVGEHLFGPYRPMNASGLVLGNPPEQPFQTYSHCVMPNGLVTSFIDSVPTDGEDYRIGGTEAPTVRIVLKGDRSFVQEEYDYGYIPAMKDVQLS |
Expression
Induction
Highly expressed at the end of the exponential phase of growth.
Interaction
Subunit
Homodimer.
Structure
Sequence
- Sequence statusComplete
- Length431
- Mass (Da)47,675
- Last updated2018-09-12 v1
- Checksum6718E045E08B57EB