3FAW | pdb_00003faw

Crystal Structure of the Group B Streptococcus Pullulanase SAP

• PDB DOI: https://doi.org/10.2210/pdb3FAW/pdb

• Classification: HYDROLASE
• Organism(s): Streptococcus agalactiae COH1
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2008-11-18 Released: 2009-04-14 
• Deposition Author(s): Gourlay, L.J.

---

Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.10 Å
• R-Value Free: 
  0.235 (Depositor), 0.243 (DCC) 
• R-Value Work: 
  0.194 (Depositor), 0.200 (DCC) 
• R-Value Observed: 
  0.196 (Depositor) 

Starting Model: experimental

Literature

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

• PubMed: 19329633 
• DOI: https://doi.org/10.1128/JB.01755-08
• Primary Citation 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.

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content 

• Total Structure Weight: 98.9 kDa 
• Atom Count: 6,593 
• Modeled Residue Count: 775 
• Deposited Residue Count: 877 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Reticulocyte binding protein	A	877	Streptococcus agalactiae COH1	Mutation(s): 0  Gene Names: SAN_1346

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
CA	B [auth A], C [auth A], D [auth A], E [auth A]	CALCIUM ION Ca BHPQYMZQTOCNFJ-UHFFFAOYSA-N
CL	F [auth A], G [auth A], H [auth A], I [auth A], J [auth A]	CHLORIDE ION Cl VEXZGXHMUGYJMC-UHFFFAOYSA-M

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.10 Å
• R-Value Free:  0.235 (Depositor), 0.243 (DCC) 
• R-Value Work:  0.194 (Depositor), 0.200 (DCC) 
• R-Value Observed: 0.196 (Depositor) 

Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 48.949	α = 90
b = 102.834	β = 90
c = 172.438	γ = 90

Software Package:

Software Name	Purpose
ADSC	data collection
MOLREP	phasing
REFMAC	refinement
MOSFLM	data reduction
SCALA	data scaling

Structure Validation

Entry History 

Deposition Data

• Released Date: 2009-04-14 
Deposition Author(s): Gourlay, L.J.

Revision History  

• Version 1.0: 2009-04-14
  Type: Initial release
  
• Version 1.1: 2011-07-13
  Changes: Version format compliance
• Version 1.2: 2023-11-01
  Changes: Data collection, Database references, Derived calculations, Refinement description