Crystal structure analysis of monofunctional alpha-2,3-sialyltransferase Cst-I from Campylobacter jejuni

Experimental Data Snapshot

  • Resolution: 1.85 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.202 
  • R-Value Observed: 0.204 

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Structural Analysis of the alpha-2,3-Sialyltransferase Cst-I from Campylobacter jejuni in Apo and Substrate-Analogue Bound Forms.

Chiu, C.P.Lairson, L.L.Gilbert, M.Wakarchuk, W.W.Withers, S.G.Strynadka, N.C.

(2007) Biochemistry 46: 7196-7204

  • DOI: https://doi.org/10.1021/bi602543d
  • Primary Citation of Related Structures:  
    2P2V, 2P56

  • PubMed Abstract: 

    Sialic acid is an essential sugar in biology that plays key roles in numerous cellular processes and interactions. The biosynthesis of sialylated glycoconjugates is catalyzed by five distinct families of sialyltransferases. In the last 25 years, there has been much research on the enzymes themselves, their genes, and their reaction products, but we still do not know the precise molecular mechanism of action for this class of glycosyltransferase. We previously reported the first detailed structural and kinetic characterization of Cst-II, a bifunctional sialyltransferase (CAZy GT-42) from the bacterium Campylobacter jejuni [Chiu et al. (2004) Nat. Struct. Mol. Biol. 11, 163-170]. This enzyme can use both Gal-beta-1,3/4-R and Neu5Ac-alpha-2,3-Gal-beta-1,3/4-R as acceptor sugars. A second sialyltransferase from this bacterium, Cst-I, has been shown to utilize solely Gal-beta-1,3/4-R as the acceptor sugar in its transferase reaction. We report here the structural and kinetic characterization of this monofunctional enzyme, which belongs to the same sialyltransferase family as Cst-II, in both apo and substrate bound form. Our structural data show that Cst-I adopts a similar GTA-type glycosyltransferase fold to that of the bifunctional Cst-II, with conservation of several key noncharged catalytic residues. Significant differences are found, however, between the two enzymes in the lid domain region, which is critical to the creation of the acceptor sugar binding site. Furthermore, molecular modeling of various acceptor sugars within the active sites of these enzymes provides significant new insights into the structural basis for substrate specificities within this biologically important enzyme class.

  • Organizational Affiliation

    Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, V6T 1Z3, Canada.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Alpha-2,3-sialyltransferase288Campylobacter jejuniMutation(s): 0 
Gene Names: cst-I
EC: 2.4.99
Find proteins for Q9RGF1 (Campylobacter jejuni)
Explore Q9RGF1 
Go to UniProtKB:  Q9RGF1
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9RGF1
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on CSF

Download Ideal Coordinates CCD File 
C20 H30 F N4 O16 P
Query on EDO

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C [auth A]
D [auth A]
E [auth A]
F [auth A]
G [auth A]
C [auth A],
D [auth A],
E [auth A],
F [auth A],
G [auth A],
H [auth A],
I [auth A],
J [auth A],
K [auth A],
L [auth A],
M [auth A],
N [auth A]
C2 H6 O2
Query on CL

Download Ideal Coordinates CCD File 
Experimental Data & Validation

Experimental Data

  • Resolution: 1.85 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.202 
  • R-Value Observed: 0.204 
  • Space Group: I 4
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 112.388α = 90
b = 112.388β = 90
c = 58.757γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-07-10
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-18
    Changes: Refinement description
  • Version 1.4: 2023-08-30
    Changes: Data collection, Database references, Derived calculations, Refinement description