DMSP-dependent demethylase from P. ubique - with cofactor THF

Experimental Data Snapshot

  • Resolution: 1.60 Å
  • R-Value Free: 0.176 
  • R-Value Work: 0.126 
  • R-Value Observed: 0.128 

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Structures of dimethylsulfoniopropionate-dependent demethylase from the marine organism Pelagabacter ubique.

Schuller, D.J.Reisch, C.R.Moran, M.A.Whitman, W.B.Lanzilotta, W.N.

(2012) Protein Sci 21: 289-298

  • DOI: https://doi.org/10.1002/pro.2015
  • Primary Citation of Related Structures:  
    3TFH, 3TFI, 3TFJ

  • PubMed Abstract: 

    Dimethylsulfoniopropionate (DMSP) is a ubiquitous algal metabolite and common carbon and sulfur source for marine bacteria. DMSP is a precursor for the climatically active gas dimethylsulfide that is readily oxidized to sulfate, sulfur dioxide, methanesulfonic acid, and other products that act as cloud condensation nuclei. Although the environmental importance of DMSP metabolism has been known for some time, the enzyme responsible for DMSP demethylation by marine bacterioplankton, dimethylsufoniopropionate-dependent demethylase A (DmdA, EC 2.1.1.B5), has only recently been identified and biochemically characterized. In this work, we report the structure for the apoenzyme DmdA from Pelagibacter ubique (2.1 Å), as well as for DmdA co-crystals soaked with substrate DMSP (1.6 Å) or the cofactor tetrahydrofolate (THF) (1.6 Å). Surprisingly, the overall fold of the DmdA is not similar to other enzymes that typically utilize the reduced form of THF and in fact is a triple domain structure similar to what has been observed for the glycine cleavage T protein or sarcosine oxidase. Specifically, while the THF binding fold appears conserved, previous biochemical studies have shown that all enzymes with a similar fold produce 5,10-methylene-THF, while DmdA catalyzes a redox-neutral methyl transfer reaction to produce 5-methyl-THF. On the basis of the findings presented herein and the available biochemical data, we outline a mechanism for a redox-neutral methyl transfer reaction that is novel to this conserved THF binding domain.

  • Organizational Affiliation

    Cornell High Energy Synchrotron Source, Cornell University, Ithaca, New York 14853, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
GcvT-like Aminomethyltransferase protein
A, B
369Candidatus Pelagibacter ubique HTCC1062Mutation(s): 0 
Gene Names: dmdASAR11_0246
Find proteins for Q4FP21 (Pelagibacter ubique (strain HTCC1062))
Explore Q4FP21 
Go to UniProtKB:  Q4FP21
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ4FP21
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 4 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on THG

Download Ideal Coordinates CCD File 
C [auth A],
G [auth B]
C19 H23 N7 O6
Query on GOL

Download Ideal Coordinates CCD File 
E [auth A],
I [auth B]
C3 H8 O3
Query on ACT

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D [auth A],
H [auth B]
C2 H3 O2
Query on NA

Download Ideal Coordinates CCD File 
F [auth A],
J [auth B]
Experimental Data & Validation

Experimental Data

  • Resolution: 1.60 Å
  • R-Value Free: 0.176 
  • R-Value Work: 0.126 
  • R-Value Observed: 0.128 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 53.746α = 90
b = 121.665β = 100.3
c = 59.336γ = 90
Software Package:
Software NamePurpose
SERGUIdata collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-12-28
    Type: Initial release
  • Version 1.1: 2012-02-29
    Changes: Database references
  • Version 1.2: 2023-09-13
    Changes: Data collection, Database references, Derived calculations, Refinement description