1MSK

METHIONINE SYNTHASE (ACTIVATION DOMAIN)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.198 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

The structure of the C-terminal domain of methionine synthase: presenting S-adenosylmethionine for reductive methylation of B12.

Dixon, M.M.Huang, S.Matthews, R.G.Ludwig, M.

(1996) Structure 4: 1263-1275

  • DOI: 10.1016/s0969-2126(96)00135-9
  • Primary Citation of Related Structures:  
    1MSK

  • PubMed Abstract: 
  • In both mammalian and microbial species, B12-dependent methionine synthase catalyzes methyl transfer from methyltetrahydrofolate (CH3-H4folate) to homocysteine. The B12 (cobalamin) cofactor plays an essential role in this reaction, accepting the meth ...

    In both mammalian and microbial species, B12-dependent methionine synthase catalyzes methyl transfer from methyltetrahydrofolate (CH3-H4folate) to homocysteine. The B12 (cobalamin) cofactor plays an essential role in this reaction, accepting the methyl group from CH3-H4folate to form methylcob(III)alamin and in turn donating the methyl group to homocysteine to generate methionine and cob(I)alamin. Occasionally the highly reactive cob(I)alamin intermediate is oxidized to the catalytically inactive cob(II)alamin form. Reactivation to sustain enzyme activity is achieved by a reductive methylation, requiring S-adenosylmethionine (AdoMet) as the methyl donor and, in Esherichia coli, flavodoxin as an electron donor. The intact system is controlled and organized so that AdoMet, rather than methyltetrahydrofolate, is the methyl donor in the reactivation reaction. AdoMet is not wasted as a methyl donor in the catalytic cycle in which methionine is synthesized from homocysteine. The structures of the AdoMet binding site and the cobalamin-binding domains (previously determined) provide a starting point for understanding the methyl transfer reactions of methionine synthase.


    Related Citations: 
    • How a Protein Binds B12: A 3.0 A X-Ray Structure of B12-Binding Domains of Methionine Synthase
      Drennan, C.L., Huang, S., Drummond, J.T., Matthews, R.G., Ludwig, M.L.
      (1994) Science 266: 1669

    Organizational Affiliation

    Biophysics Research Division, University of Michigan, 930 N. University, Ann Arbor, MI 48109-1055, USA. ludwig@biop.umich.edu



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
COBALAMIN-DEPENDENT METHIONINE SYNTHASEA331Escherichia coli K-12Mutation(s): 0 
Gene Names: metHb4019JW3979
EC: 2.1.1.13
Find proteins for P13009 (Escherichia coli (strain K12))
Explore P13009 
Go to UniProtKB:  P13009
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SAM
Query on SAM

Download CCD File 
A
S-ADENOSYLMETHIONINE
C15 H22 N6 O5 S
MEFKEPWMEQBLKI-FCKMPRQPSA-N
 Ligand Interaction
ACT
Query on ACT

Download CCD File 
A
ACETATE ION
C2 H3 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-M
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.198 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 38.86α = 90
b = 62.36β = 90
c = 140.82γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
ADSCdata collection
X-PLORphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1997-04-01
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance