Structural analysis of the C-terminal domain of murine CMP-Sialic acid Synthetase

Experimental Data Snapshot

  • Resolution: 1.90 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.206 
  • R-Value Observed: 0.209 

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This is version 1.3 of the entry. See complete history


A C-terminal phosphatase module conserved in vertebrate CMP-sialic acid synthetases provides a tetramerization interface for the physiologically active enzyme.

Oschlies, M.Dickmanns, A.Haselhorst, T.Schaper, W.Stummeyer, K.Tiralongo, J.Weinhold, B.Gerardy-Schahn, R.von Itzstein, M.Ficner, R.Munster-Kuhnel, A.K.

(2009) J Mol Biol 393: 83-97

  • DOI: https://doi.org/10.1016/j.jmb.2009.08.003
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The biosynthesis of sialic acid-containing glycoconjugates is crucial for the development of vertebrate life. Cytidine monophosphate-sialic acid synthetase (CSS) catalyzes the metabolic activation of sialic acids. In vertebrates, the enzyme is chimeric, with the N-terminal domain harboring the synthetase activity. The function of the highly conserved C-terminal domain (CSS-CT) is unknown. To shed light on its biological function, we solved the X-ray structure of murine CSS-CT to 1.9 A resolution. CSS-CT is a stable shamrock-like tetramer that superimposes well with phosphatases of the haloacid dehalogenase superfamily. However, a region found exclusively in vertebrate CSS-CT appears to block the active-site entrance. Accordingly, no phosphatase activity was observed in vitro, which points toward a nonenzymatic function of CSS-CT. A computational three-dimensional model of full-length CSS, in combination with in vitro oligomerization studies, provides evidence that CSS-CT serves as a platform for the quaternary organization governing the kinetic properties of the physiologically active enzyme as demonstrated in kinetic studies.

  • Organizational Affiliation

    Institut für Zelluläre Chemie, Medizinische Hochschule Hannover, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
N-acylneuraminate cytidylyltransferase
A, B
168Mus musculusMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for Q99KK2 (Mus musculus)
Explore Q99KK2 
Go to UniProtKB:  Q99KK2
IMPC:  MGI:1337124
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ99KK2
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.90 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.206 
  • R-Value Observed: 0.209 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 121.09α = 90
b = 37.49β = 116.3
c = 78.83γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
HKL-2000data collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-08-18
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2017-10-25
    Changes: Refinement description
  • Version 1.3: 2023-12-27
    Changes: Data collection, Database references