1RG9

S-Adenosylmethionine synthetase complexed with SAM and PPNP


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.211 

wwPDB Validation 3D Report Full Report


This is version 1.4 of the entry. See complete history

Literature

Crystal structure of the S-adenosylmethionine synthetase ternary complex: a novel catalytic mechanism of s-adenosylmethionine synthesis from ATP and MET.

Komoto, J.Yamada, T.Takata, Y.Markham, G.D.Takusagawa, F.

(2004) Biochemistry 43: 1821-1831

  • DOI: 10.1021/bi035611t
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • S-Adenosylmethionine synthetase (MAT) catalyzes formation of S-adenosylmethionine (SAM) from ATP and l-methionine (Met) and hydrolysis of tripolyphosphate to PP(i) and P(i). Escherichia coli MAT (eMAT) has been crystallized with the ATP analogue AMPP ...

    S-Adenosylmethionine synthetase (MAT) catalyzes formation of S-adenosylmethionine (SAM) from ATP and l-methionine (Met) and hydrolysis of tripolyphosphate to PP(i) and P(i). Escherichia coli MAT (eMAT) has been crystallized with the ATP analogue AMPPNP and Met, and the crystal structure has been determined at 2.5 A resolution. eMAT is a dimer of dimers and has a 222 symmetry. Each active site contains the products SAM and PPNP. A modeling study indicates that the substrates (AMPPNP and Met) can bind at the same sites as the products, and only a small conformation change of the ribose ring is needed for conversion of the substrates to the products. On the basis of the ternary complex structure and a modeling study, a novel catalytic mechanism of SAM formation is proposed. In the mechanism, neutral His14 acts as an acid to cleave the C5'-O5' bond of ATP while simultaneously a change in the ribose ring conformation from C4'-exo to C3'-endo occurs, and the S of Met makes a nucleophilic attack on the C5' to form SAM. All essential amino acid residues for substrate binding found in eMAT are conserved in the rat liver enzyme, indicating that the bacterial and mammalian enzymes have the same catalytic mechanism. However, a catalytic mechanism proposed recently by González et al. based on the structures of three ternary complexes of rat liver MAT [González, B., Pajares, M. A., Hermoso, J. A., Guillerm, D., Guillerm, G., and Sanz-Aparicio. J. (2003) J. Mol. Biol. 331, 407] is substantially different from our mechanism.


    Organizational Affiliation

    Department of Molecular Biosciences, University of Kansas, 1200 Sunnyside Avenue, Lawrence, Kansas 66045-7534, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
S-adenosylmethionine synthetase
A, B, C, D
383Escherichia coli (strain K12)Mutation(s): 0 
Gene Names: metK (metX)
EC: 2.5.1.6
Find proteins for P0A817 (Escherichia coli (strain K12))
Go to UniProtKB:  P0A817
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
K
Query on K

Download SDF File 
Download CCD File 
A, B, C, D
POTASSIUM ION
K
NPYPAHLBTDXSSS-UHFFFAOYSA-N
 Ligand Interaction
PPK
Query on PPK

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Download CCD File 
A, B, C, D
(DIPHOSPHONO)AMINOPHOSPHONIC ACID
H6 N O9 P3
PELPUMGXMYVGSQ-UHFFFAOYSA-N
 Ligand Interaction
MG
Query on MG

Download SDF File 
Download CCD File 
A, B, C, D
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
SAM
Query on SAM

Download SDF File 
Download CCD File 
A, B, C
S-ADENOSYLMETHIONINE
C15 H22 N6 O5 S
MEFKEPWMEQBLKI-FCKMPRQPSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.211 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 225.820α = 90.00
b = 69.130β = 90.00
c = 118.230γ = 90.00
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
X-PLORphasing
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-03-02
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-10-11
    Type: Refinement description
  • Version 1.4: 2018-04-04
    Type: Data collection