Q71RT3 · LSCB_PSESG

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).

Catalytic activity

Features

Showing features for binding site, active site, site.

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TypeIDPosition(s)Description
Binding site61sucrose (UniProtKB | ChEBI)
Active site62Nucleophile
Binding site62sucrose (UniProtKB | ChEBI)
Binding site148sucrose (UniProtKB | ChEBI)
Binding site218sucrose (UniProtKB | ChEBI)
Binding site219sucrose (UniProtKB | ChEBI)
Site219Transition state stabilizer
Active site303Proton donor/acceptor

GO annotations

AspectTerm
Cellular Componentextracellular region
Molecular Functionlevansucrase activity
Biological Processcarbohydrate utilization

Keywords

Enzyme and pathway databases

Protein family/group databases

Names & Taxonomy

Protein names

  • Recommended name
    Levansucrase LscB
  • EC number
  • Alternative names
    • Sucrose 6-fructosyltransferase

Gene names

    • Name
      lscB

Encoded on

  • Plasmid p4180D

Organism names

Accessions

  • Primary accession
    Q71RT3

Subcellular Location

Secreted
Note: Secreted in a temperature-dependent manner (PubMed:17147762).
Secretion at low temperature is due to a combination of thermo-regulated transcription and secretion (PubMed:17147762).

Keywords

Phenotypes & Variants

Disruption phenotype

Disruption mutant does not exhibit a levan-deficient phenotype (PubMed:11344135).
The lscB-lscC double mutant is completely defective in levan formation and can be complemented by either lscB or lscC (PubMed:11344135).

PTM/Processing

Features

Showing features for chain.

TypeIDPosition(s)Description
ChainPRO_00004597491-431Levansucrase LscB

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).

Structure

Family & Domains

Sequence similarities

Belongs to the glycosyl hydrolase 68 family.

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    431
  • Mass (Da)
    47,603
  • Last updated
    2004-07-05 v1
  • Checksum
    795FEA246D40C40F
MSTSSSAVSQLKNSPLAGNINYEPTVWSRADALKVNENDPTTTQPLVSADFPVMSDTVFIWDTMPLRELDGTVVSVNGWSVILTLTADRHPNDPQYLDANGRYDIKRDWEDRHGRARMSYWYSRTGKDWIFGGRVMAEGVSPTTREWAGTPILLNDKGDIDLYYTCVTPGAAIAKVRGRIVTSDQGVELKDFTQVKKLFEADGTYYQTEAQNSSWNFRDPSPFIDPNDGKLYMVFEGNVAGERGSHTVGAAELGPVPPGHEDVGGARFQVGCIGLAVAKDLSGEEWEILPPLVTAVGVNDQTERPHYVFQDGKYYLFTISHKFTYAEGLTGPDGVYGFVGEHLFGPYRPMNASGLVLGNPPEQPFQTYSHCVMPNGLVTSFIDSVPTEGEDYRIGGTEAPTVRILLKGDRSFVQEEYDYGYIPAMKDVTLS

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
AF345638
EMBL· GenBank· DDBJ
AAK49951.1
EMBL· GenBank· DDBJ
Genomic DNA

Similar Proteins

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