Experimental Data Snapshot

  • Resolution: 2.79 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.205 
  • R-Value Observed: 0.207 

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Structural and Mechanistic Analysis of the Choline Sulfatase from Sinorhizobium melliloti: A Class I Sulfatase Specific for an Alkyl Sulfate Ester.

van Loo, B.Schober, M.Valkov, E.Heberlein, M.Bornberg-Bauer, E.Faber, K.Hyvonen, M.Hollfelder, F.

(2018) J Mol Biol 430: 1004-1023

  • DOI: https://doi.org/10.1016/j.jmb.2018.02.010
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Hydrolysis of organic sulfate esters proceeds by two distinct mechanisms, water attacking at either sulfur (S-O bond cleavage) or carbon (C-O bond cleavage). In primary and secondary alkyl sulfates, attack at carbon is favored, whereas in aromatic sulfates and sulfated sugars, attack at sulfur is preferred. This mechanistic distinction is mirrored in the classification of enzymes that catalyze sulfate ester hydrolysis: arylsulfatases (ASs) catalyze S-O cleavage in sulfate sugars and arylsulfates, and alkyl sulfatases break the C-O bond of alkyl sulfates. Sinorhizobium meliloti choline sulfatase (SmCS) efficiently catalyzes the hydrolysis of alkyl sulfate choline-O-sulfate (k cat /K M =4.8×10 3 s -1 M -1 ) as well as arylsulfate 4-nitrophenyl sulfate (k cat /K M =12s -1 M -1 ). Its 2.8-Å resolution X-ray structure shows a buried, largely hydrophobic active site in which a conserved glutamate (Glu386) plays a role in recognition of the quaternary ammonium group of the choline substrate. SmCS structurally resembles members of the alkaline phosphatase superfamily, being most closely related to dimeric ASs and tetrameric phosphonate monoester hydrolases. Although >70% of the amino acids between protomers align structurally (RMSDs 1.79-1.99Å), the oligomeric structures show distinctly different packing and protomer-protomer interfaces. The latter also play an important role in active site formation. Mutagenesis of the conserved active site residues typical for ASs, H 2 18 O-labeling studies and the observation of catalytically promiscuous behavior toward phosphoesters confirm the close relation to alkaline phosphatase superfamily members and suggest that SmCS is an AS that catalyzes S-O cleavage in alkyl sulfate esters with extreme catalytic proficiency.

  • Organizational Affiliation

    Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, United Kingdom. Electronic address: fh111@cam.ac.uk.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C, D, E
A, B, C, D, E, F, G, H
515Sinorhizobium meliloti 1021Mutation(s): 0 
Gene Names: betCR00949SMc00127
Find proteins for O69787 (Rhizobium meliloti (strain 1021))
Explore O69787 
Go to UniProtKB:  O69787
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO69787
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.79 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.205 
  • R-Value Observed: 0.207 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 119.556α = 90
b = 163.248β = 94.4
c = 177.625γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
Aimlessdata scaling

Structure Validation

View Full Validation Report

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Biotechnology and Biological Sciences Research CouncilUnited KingdomBBI004327/1

Revision History  (Full details and data files)

  • Version 1.0: 2018-02-28
    Type: Initial release
  • Version 1.1: 2018-04-04
    Changes: Author supporting evidence, Data collection, Database references