4FS8

The structure of an As(III) S-adenosylmethionine methyltransferase: insights into the mechanism of arsenic biotransformation


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.78 Å
  • R-Value Free: 0.205 
  • R-Value Work: 0.177 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Structure of an As(III) S-Adenosylmethionine Methyltransferase: Insights into the Mechanism of Arsenic Biotransformation.

Ajees, A.A.Marapakala, K.Packianathan, C.Sankaran, B.Rosen, B.P.

(2012) Biochemistry 51: 5476-5485

  • DOI: 10.1021/bi3004632
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Enzymatic methylation of arsenic is a detoxification process in microorganisms but in humans may activate the metalloid to more carcinogenic species. We describe the first structure of an As(III) S-adenosylmethionine methyltransferase by X-ray crysta ...

    Enzymatic methylation of arsenic is a detoxification process in microorganisms but in humans may activate the metalloid to more carcinogenic species. We describe the first structure of an As(III) S-adenosylmethionine methyltransferase by X-ray crystallography that reveals a novel As(III) binding domain. The structure of the methyltransferase from the thermophilic eukaryotic alga Cyanidioschyzon merolae reveals the relationship between the arsenic and S-adenosylmethionine binding sites to a final resolution of ∼1.6 Å. As(III) binding causes little change in conformation, but binding of SAM reorients helix α4 and a loop (residues 49-80) toward the As(III) binding domain, positioning the methyl group for transfer to the metalloid. There is no evidence of a reductase domain. These results are consistent with previous suggestions that arsenic remains trivalent during the catalytic cycle. A homology model of human As(III) S-adenosylmethionine methyltransferase with the location of known polymorphisms was constructed. The structure provides insights into the mechanism of substrate binding and catalysis.


    Related Citations: 
    • Crystallization and preliminary X-ray crystallographic analysis of the ArsM arsenic(III) S-adenosylmethionine methyltransferase.
      Marapakala, K.,Ajees, A.A.,Qin, J.,Sankaran, B.,Rosen, B.P.
      (2010) Acta Crystallogr.,Sect.F 66: 1050


    Organizational Affiliation

    Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, 33199, United States.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Arsenic methyltransferase
A
383Cyanidioschyzon sp. 5508Mutation(s): 0 
Gene Names: arsM
Find proteins for C0JV69 (Cyanidioschyzon sp. 5508)
Go to UniProtKB:  C0JV69
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download SDF File 
Download CCD File 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.78 Å
  • R-Value Free: 0.205 
  • R-Value Work: 0.177 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 84.750α = 90.00
b = 47.198β = 115.67
c = 101.677γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data scaling
HKL-2000data reduction
PHASERphasing
ADSCdata collection
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-07-11
    Type: Initial release
  • Version 1.1: 2012-10-03
    Type: Database references