Biological Assembly 1  

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Global Symmetry: Cyclic - C2  (3D View)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 57107.07 
• Atom Count: 3998 
• Residue Count: 492 
• Unique protein chains: 1

1BMT

HOW A PROTEIN BINDS B12: A 3.O ANGSTROM X-RAY STRUCTURE OF THE B12-BINDING DOMAINS OF METHIONINE SYNTHASE

• DOI: 10.2210/pdb1BMT/pdb

• Classification: METHYLTRANSFERASE
• Organism(s): Escherichia coli (strain K12)


• Deposited: 1994-09-02 Released: 1995-06-03 
• Deposition Author(s): Drennan, C.L., Huang, S., Drummond, J.T., Matthews, R.G., Ludwig, M.L.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 3 Å
• R-Value Work: 0.170 

Literature

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., Lidwig, M.L.

(1994) Science 266: 1669-1674

• PubMed: 7992050 


• PubMed Abstract: 
  

The crystal structure of a 27-kilodalton methylcobalamin-containing fragment of methionine synthase from Escherichia coli was determined at 3.0 A resolution. This structure depicts cobalamin-protein interactions and reveals that the corrin macrocycle lies between a helical amino-terminal domain and an alpha/beta carboxyl-terminal domain that is a variant of the Rossmann fold. Methylcobalamin undergoes a conformational change on binding the protein; the dimethylbenzimidazole group, which is coordinated to the cobalt in the free cofactor, moves away from the corrin and is replaced by a histidine contributed by the protein. The sequence Asp-X-His-X-X-Gly, which contains this histidine ligand, is conserved in the adenosylcobalamin-dependent enzymes methylmalonyl-coenzyme A mutase and glutamate mutase, suggesting that displacement of the dimethylbenzimidazole will be a feature common to many cobalamin-binding proteins. Thus the cobalt ligand, His759, and the neighboring residues Asp757 and Ser810, may form a catalytic quartet, Co-His-Asp-Ser, that modulates the reactivity of the B12 prosthetic group in methionine synthase.

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Related Citations: 

• Cobalamin-Dependent Methionine Synthase: The Structure of a Methylcobalamin-Binding Fragment and Implications for Other B12-Dependent Enzymes
  Drennan, C.L.,Matthews, R.G.,Ludwig, M.L.
  (1994) Curr.Opin.Struct.Biol. 4: 919




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Organizational Affiliation: 

Biophysics Research Division, University of Michigan, Ann Arbor 48109-1055.

Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
METHIONINE SYNTHASE	A, B	246	Escherichia coli (strain K12)	Mutation(s): 0  Gene Names: metH EC: 2.1.1.13
Find proteins for P13009 (Escherichia coli (strain K12)) Go to UniProtKB:  P13009

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram & Interactions
COB	A, B	CO-METHYLCOBALAMIN C63 H91 Co N13 O14 P BMOGZGJBQIUQJG-BYLSPCLQSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 3 Å
• R-Value Work: 0.170 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length (Å)	Angle (°)
a = 96.700	α = 90.00
b = 55.300	β = 90.00
c = 103.800	γ = 90.00

Software Package:

Software Name	Purpose
X-PLOR	phasing
X-PLOR	model building
X-PLOR	refinement

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 1994-09-02 
• Released Date: 1995-06-03 
• Deposition Author(s): Drennan, C.L., Huang, S., Drummond, J.T., Matthews, R.G., Ludwig, M.L.

Revision History 

• Version 1.0: 1995-06-03
  Type: Initial release
• Version 1.1: 2008-03-24
  Type: Version format compliance
• Version 1.2: 2011-07-13
  Type: Version format compliance