Structure of BT4661, a SusE-like surface located polysaccharide binding protein from the Bacteroides thetaiotaomicron heparin utilisation locus

Experimental Data Snapshot

  • Resolution: 1.95 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.216 
  • R-Value Observed: 0.217 

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How members of the human gut microbiota overcome the sulfation problem posed by glycosaminoglycans.

Cartmell, A.Lowe, E.C.Basle, A.Firbank, S.J.Ndeh, D.A.Murray, H.Terrapon, N.Lombard, V.Henrissat, B.Turnbull, J.E.Czjzek, M.Gilbert, H.J.Bolam, D.N.

(2017) Proc Natl Acad Sci U S A 114: 7037-7042

  • DOI: https://doi.org/10.1073/pnas.1704367114
  • Primary Citation of Related Structures:  
    4AK1, 4AK2, 5G2T, 5G2U, 5G2V

  • PubMed Abstract: 

    The human microbiota, which plays an important role in health and disease, uses complex carbohydrates as a major source of nutrients. Utilization hierarchy indicates that the host glycosaminoglycans heparin (Hep) and heparan sulfate (HS) are high-priority carbohydrates for Bacteroides thetaiotaomicron , a prominent member of the human microbiota. The sulfation patterns of these glycosaminoglycans are highly variable, which presents a significant enzymatic challenge to the polysaccharide lyases and sulfatases that mediate degradation. It is possible that the bacterium recruits lyases with highly plastic specificities and expresses a repertoire of enzymes that target substructures of the glycosaminoglycans with variable sulfation or that the glycans are desulfated before cleavage by the lyases. To distinguish between these mechanisms, the components of the B. thetaiotaomicron Hep/HS degrading apparatus were analyzed. The data showed that the bacterium expressed a single-surface endo-acting lyase that cleaved HS, reflecting its higher molecular weight compared with Hep. Both Hep and HS oligosaccharides imported into the periplasm were degraded by a repertoire of lyases, with each enzyme displaying specificity for substructures within these glycosaminoglycans that display a different degree of sulfation. Furthermore, the crystal structures of a key surface glycan binding protein, which is able to bind both Hep and HS, and periplasmic sulfatases reveal the major specificity determinants for these proteins. The locus described here is highly conserved within the human gut Bacteroides , indicating that the model developed is of generic relevance to this important microbial community.

  • Organizational Affiliation

    Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
BT_4661708Bacteroides thetaiotaomicron VPI-5482Mutation(s): 0 
Find proteins for Q89YS0 (Bacteroides thetaiotaomicron (strain ATCC 29148 / DSM 2079 / JCM 5827 / CCUG 10774 / NCTC 10582 / VPI-5482 / E50))
Explore Q89YS0 
Go to UniProtKB:  Q89YS0
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ89YS0
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.95 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.216 
  • R-Value Observed: 0.217 
  • Space Group: P 63 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 158.62α = 90
b = 158.62β = 90
c = 137.06γ = 120
Software Package:
Software NamePurpose
iMOSFLMdata reduction
SCALAdata scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-03-06
    Type: Initial release
  • Version 2.0: 2018-12-12
    Changes: Atomic model, Data collection, Database references, Refinement description