Biological Assembly 1  

 3D View: Structure | Electron Density | Ligand Interaction

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Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 17821.23 
• Atom Count: 1259 
• Residue Count: 153 
• Unique protein chains: 1

2O5Q

Manganese horse heart myoglobin, nitric oxide modified

• DOI: 10.2210/pdb2O5Q/pdb

• Classification: OXYGEN STORAGE/TRANSPORT
• Organism(s): Equus caballus


• Deposited: 2006-12-06 Released: 2007-10-16 
• Deposition Author(s): Richter-Addo, G.B., Zahran, Z.N., Chooback, L., Copeland, D.M., West, A.H.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.9 Å
• R-Value Free: 0.235 
• R-Value Work: 0.177 

Literature

Crystal structures of manganese- and cobalt-substituted myoglobin in complex with NO and nitrite reveal unusual ligand conformations.

Zahran, Z.N., Chooback, L., Copeland, D.M., West, A.H., Richter-Addo, G.B.

(2008) J.Inorg.Biochem. 102: 216-233

• PubMed: 17905436 
• DOI: 10.1016/j.jinorgbio.2007.08.002
• Primary Citation of Related Structures:  
  2O5T, 2O5S, 2O5O, 2O5M, 2O5L, 2O5B, 2O58


• PubMed Abstract: 
  

Nitrite is now recognized as a storage pool of bioactive nitric oxide (NO). Hemoglobin (Hb) and myoglobin (Mb) convert, under certain conditions, nitrite to NO. This newly discovered nitrite reductase activity of Hb and Mb provides an attractive alternative to mammalian NO synthesis from the NO synthase pathway that requires dioxygen. We recently reported the X-ray crystal structure of the nitrite adduct of ferric horse heart Mb, and showed that the nitrite ligand binds in an unprecedented O-binding (nitrito) mode to the d(5) ferric center in Mb(III)(ONO) [D.M. Copeland, A. Soares, A.H. West, G.B. Richter-Addo, J. Inorg. Biochem. 100 (2006) 1413-1425]. We also showed that the distal pocket in Mb allows for different conformations of the NO ligand (120 degrees and 144 degrees ) in Mb(II)NO depending on the mode of preparation of the compound. In this article, we report the crystal structures of the nitrite and NO adducts of manganese-substituted hh Mb (a d(4) system) and of the nitrite adduct of cobalt-substituted hh Mb (a d(6) system). We show that the distal His64 residue directs the nitrite ligand towards the rare nitrito O-binding mode in Mn(III)Mb and Co(III)Mb. We also report that the distal pocket residues allow a stabilization of an unprecendented bent MnNO moiety in Mn(II)MbNO. These crystal structural data, when combined with the data for the aquo, methanol, and azide MnMb derivatives, provide information on the role of distal pocket residues in the observed binding modes of nitrite and NO ligands to wild-type and metal-substituted Mb.

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Organizational Affiliation: 

The Department of Chemistry and Biochemistry, University of Oklahoma, 620 Parrington Oval, Norman, OK 73019, United States.

Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
Myoglobin	X	153	Equus caballus	Mutation(s): 0  Gene Names: MB
Find proteins for P68082 (Equus caballus) Go to Gene View: MB Go to UniProtKB:  P68082

Small Molecules

Ligands 3 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram & Interactions
SO4	X	SULFATE ION O4 S QAOWNCQODCNURD-UHFFFAOYSA-L
MNH	X	MANGANESE PROTOPORPHYRIN IX C34 H32 Mn N4 O4 UIBYYPDLEONCGQ-RGGAHWMASA-L
NO	X	NITRIC OXIDE Nitrogen monoxide N O ODUCDPQEXGNKDN-UHFFFAOYAM

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.9 Å
• R-Value Free: 0.235 
• R-Value Work: 0.177 
• Space Group: P 1 2₁ 1

Unit Cell:

Length (Å)	Angle (°)
a = 35.468	α = 90.00
b = 28.637	β = 105.70
c = 63.193	γ = 90.00

Software Package:

Software Name	Purpose
CrystalClear	data collection
MOLREP	phasing
REFMAC	refinement
d*TREK	data reduction
d*TREK	data scaling

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2006-12-06 
• Released Date: 2007-10-16 
• Deposition Author(s): Richter-Addo, G.B., Zahran, Z.N., Chooback, L., Copeland, D.M., West, A.H.

Revision History 

• Version 1.0: 2007-10-16
  Type: Initial release
• Version 1.1: 2011-07-13
  Type: Version format compliance