Q71RT3 · LSCB_PSESG
- ProteinLevansucrase LscB
- GenelscB
- 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.
Miscellaneous
Strain PG4180 contains three levansucrase-encoding genes: lscA, lscB and lscC (PubMed:11344135).
Of the three copies, only lscB and lscC have been shown to be expressed while no expression was observed for lscA under the tested growth conditions (PubMed:11344135).
Of the three copies, only lscB and lscC have been shown to be expressed while no expression was observed for lscA under the tested growth conditions (PubMed:11344135).
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
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 | |
---|---|---|
Cellular Component | extracellular region | |
Molecular Function | levansucrase activity | |
Biological Process | carbohydrate utilization |
Keywords
- Molecular function
- Biological process
Enzyme and pathway databases
Protein family/group databases
Names & Taxonomy
Protein names
- Recommended nameLevansucrase LscB
- EC number
- Alternative names
Gene names
Encoded on
- Plasmid p4180D
Organism names
- Strain
- Taxonomic lineageBacteria > Pseudomonadota > Gammaproteobacteria > Pseudomonadales > Pseudomonadaceae > Pseudomonas
Accessions
- Primary accessionQ71RT3
PTM/Processing
Features
Showing features for chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Chain | PRO_0000459749 | 1-431 | Levansucrase LscB | |||
Sequence: MSTSSSAVSQLKNSPLAGNINYEPTVWSRADALKVNENDPTTTQPLVSADFPVMSDTVFIWDTMPLRELDGTVVSVNGWSVILTLTADRHPNDPQYLDANGRYDIKRDWEDRHGRARMSYWYSRTGKDWIFGGRVMAEGVSPTTREWAGTPILLNDKGDIDLYYTCVTPGAAIAKVRGRIVTSDQGVELKDFTQVKKLFEADGTYYQTEAQNSSWNFRDPSPFIDPNDGKLYMVFEGNVAGERGSHTVGAAELGPVPPGHEDVGGARFQVGCIGLAVAKDLSGEEWEILPPLVTAVGVNDQTERPHYVFQDGKYYLFTISHKFTYAEGLTGPDGVYGFVGEHLFGPYRPMNASGLVLGNPPEQPFQTYSHCVMPNGLVTSFIDSVPTEGEDYRIGGTEAPTVRILLKGDRSFVQEEYDYGYIPAMKDVTLS |
Expression
Induction
The upstream region of the gene contains a phage-associated promoter element (PAPE), which also includes the first 48 nucleotides of lscB and is essential for expression of the gene (PubMed:24670199).
Even though the upstream region of the gene is sufficient to promote expression, the expression level is enhanced by the presence of the 48-bp N-terminus of lscB (PubMed:24670199).
Expression is induced by the transcriptional regulator LscR, which is able to bind specifically to lsc upstream PAPE sequence (PubMed:27664099).
Transcription is temperature-dependent (PubMed:17147762).
Expression is strongest during growth in early logarithmic phase at 18 degrees Celsius, a temperature fostering virulence of this pathogen (PubMed:17147762).
Even though the upstream region of the gene is sufficient to promote expression, the expression level is enhanced by the presence of the 48-bp N-terminus of lscB (PubMed:24670199).
Expression is induced by the transcriptional regulator LscR, which is able to bind specifically to lsc upstream PAPE sequence (PubMed:27664099).
Transcription is temperature-dependent (PubMed:17147762).
Expression is strongest during growth in early logarithmic phase at 18 degrees Celsius, a temperature fostering virulence of this pathogen (PubMed:17147762).
Structure
Sequence
- Sequence statusComplete
- Length431
- Mass (Da)47,603
- Last updated2004-07-05 v1
- Checksum795FEA246D40C40F
Keywords
- Technical term