The crystal structure of GBS pullulanase SAP in complex with maltotetraose

Experimental Data Snapshot

  • Resolution: 2.40 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.221 
  • R-Value Observed: 0.224 

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Group B Streptococcus pullulanase crystal structures in the context of a novel strategy for vaccine development

Gourlay, L.J.Santi, I.Pezzicoli, A.Grandi, G.Soriani, M.Bolognesi, M.

(2009) J Bacteriol 191: 3544-3552

  • DOI: https://doi.org/10.1128/JB.01755-08
  • Primary Citation of Related Structures:  
    3FAW, 3FAX

  • PubMed Abstract: 

    The group B streptococcus type I pullulanase (SAP) is a class 13 glycoside hydrolase that is anchored to the bacterial cell surface via a conserved C-terminal anchoring motif and involved in alpha-glucan degradation. Recent in vitro functional studies have shown that SAP is immunogenic in humans and that anti-SAP sera derived from immunized animals impair both group A and group B streptococcus pullulanase activities, suggesting that in vivo immunization with this antigen could prevent streptococcal colonization. To further investigate the putative role of SAP in bacterial pathogenesis, we carried out functional studies and found that recombinant SAP binds to human cervical epithelial cells. Furthermore, with a view of using SAP as a vaccine candidate, we present high-resolution crystal structure analyses of an N-terminally truncated form of SAP lacking the carbohydrate binding module but containing the catalytic domain and displaying glycosidase hydrolase activity, both in its apo form and in complex with maltotetraose, at resolutions of 2.1 and 2.4 A, respectively.

  • Organizational Affiliation

    Department of Biomolecular Sciences and Biotechnology, University of Milan, Via Celoria 26, I-20133 Milan, Italy.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Reticulocyte binding protein877Streptococcus agalactiae COH1Mutation(s): 0 
Gene Names: SAN_1346
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
  • Reference Sequence


Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
Glycosylation Resources
GlyTouCan:  G00395FS
GlyCosmos:  G00395FS
GlyGen:  G00395FS
Biologically Interesting Molecules (External Reference) 1 Unique
Experimental Data & Validation

Experimental Data

  • Resolution: 2.40 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.221 
  • R-Value Observed: 0.224 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 48.214α = 90
b = 102.862β = 90
c = 171.69γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-04-14
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Database references, Derived calculations, Structure summary
  • Version 2.1: 2023-11-01
    Changes: Data collection, Database references, Refinement description, Structure summary