2MHB

THE STRUCTURE OF HORSE METHAEMOGLOBIN AT 2.0 ANGSTROMS RESOLUTION

• PDB DOI: https://doi.org/10.2210/pdb2MHB/pdb
• Entry: 2MHB supersedes: 1MHB

• Classification: OXYGEN TRANSPORT
• Organism(s): Equus caballus
• Mutation(s): No 


• Deposited: 1977-02-14 Released: 1983-01-20 
• Deposition Author(s): Ladner, R.C., Heidner, E.G., Perutz, M.F.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.00 Å
• R-Value Work: 0.230 
• R-Value Observed: 0.230 

Re-refinement Note

A newer entry is available that reflects an alternative modeling of the original data: 1G0B

Literature

The structure of horse methaemoglobin at 2-0 A resolution.

Ladner, R.C., Heidner, E.J., Perutz, M.F.

(1977) J Mol Biol 114: 385-414

• PubMed: 561852 
• DOI: https://doi.org/10.1016/0022-2836(77)90256-x
• Primary Citation of Related Structures:  
  2MHB

Biological Assembly 1  

Global Symmetry: Cyclic - C2  (Explore in 3D)
Global Stoichiometry: Hetero 4-mer - A2B2 Pseudo Symmetry: Dihedral - D2  (Explore in 3D)
Pseudo Stoichiometry: Homo 4-mer - A4 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 32.4 kDa 
• Atom Count: 2,291 
• Modelled Residue Count: 287 
• Deposited Residue Count: 287 
• Unique protein chains: 2

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
HEMOGLOBIN (AQUO MET) (ALPHA CHAIN)	A	141	Equus caballus	Mutation(s): 0
UniProt
Find proteins for P01958 (Equus caballus) Explore P01958  Go to UniProtKB:  P01958

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
HEMOGLOBIN (AQUO MET) (BETA CHAIN)	B	146	Equus caballus	Mutation(s): 0
UniProt
Find proteins for P02062 (Equus caballus) Explore P02062  Go to UniProtKB:  P02062

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
HEM	C [auth A], D [auth B]	PROTOPORPHYRIN IX CONTAINING FE C34 H32 Fe N4 O4 KABFMIBPWCXCRK-RGGAHWMASA-L

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.00 Å
• R-Value Work: 0.230 
• R-Value Observed: 0.230 
• Space Group: C 1 2 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 108.24	α = 90
b = 63.13	β = 110.85
c = 54.54	γ = 90

Structure Validation

Entry History 

Deposition Data

• Released Date: 1983-01-20 
Deposition Author(s): Ladner, R.C., Heidner, E.G., Perutz, M.F.
• This entry supersedes: 1MHB

Revision History  

• Version 1.0: 1983-01-20
  Type: Initial release
  
• Version 1.1: 2008-03-03
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance
• Version 1.3: 2012-11-28
  Changes: Other
• Version 1.4: 2024-12-25
  Changes: Advisory, Data collection, Database references, Derived calculations, Structure summary