1TES

OXYGEN BINDING MUSCLE PROTEIN


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.7 Å
  • R-Value Work: 0.159 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Mechanism of NO-induced oxidation of myoglobin and hemoglobin.

Eich, R.F.Li, T.Lemon, D.D.Doherty, D.H.Curry, S.R.Aitken, J.F.Mathews, A.J.Johnson, K.A.Smith, R.D.Phillips Jr., G.N.Olson, J.S.

(1996) Biochemistry 35: 6976-6983

  • DOI: 10.1021/bi960442g

  • PubMed Abstract: 
  • Nitric oxide (NO) has been implicated as mediator in a variety of physiological functions, including neurotransmission, platelet aggregation, macrophage function, and vasodilation. The consumption of NO by extracellular hemoglobin and subsequent vaso ...

    Nitric oxide (NO) has been implicated as mediator in a variety of physiological functions, including neurotransmission, platelet aggregation, macrophage function, and vasodilation. The consumption of NO by extracellular hemoglobin and subsequent vasoconstriction have been suggested to be the cause of the mild hypertensive events reported during in vivo trials of hemoglobin-based O2 carriers. The depletion of NO from endothelial cells is most likely due to the oxidative reaction of NO with oxyhemoglobin in arterioles and surrounding tissue. In order to determine the mechanism of this key reaction, we have measured the kinetics of NO-induced oxidation of a variety of different recombinant sperm whale myoglobins (Mb) and human hemoglobins (Hb). The observed rates depend linearly on [NO] but show no dependence on [O2]. The bimolecular rate constants for NO-induced oxidation of MbO2 and HbO2 are large (k.ox,NO = 30-50 microM-1 s-1 for the wild-type proteins) and similar to those for simple nitric oxide binding to deoxygenated Mb and Hb. Both reversible NO binding and NO-induced oxidation occur in two steps: (1) bimolecular entry of nitric oxide into the distal portion of the heme pocket and (2) rapid reaction of noncovalently bound nitric oxide with the iron atom to produce Fe(2+)-N=O or with Fe(2+)-O-O delta- to produce Fe(3+)-OH2 and nitrate. Both the oxidation and binding rate constants for sperm whale Mb were increased when His(E7) was replaced by aliphatic residues. These mutants lack polar interactions in the distal pocket which normally hinder NO entry into the protein. Decreasing the volume of the distal pocket by replacing Leu(B10) and Val(E11) with aromatic amino acids markedly inhibits NO-induced oxidation of MbO2. The latter results provide a protein engineering strategy for reducing hypertensive events caused by extracellular hemoglobin-based O2 carriers. This approach has been explored by examining the effects of Phe(B10) and Phe(E11) substitutions on the rates of NO-induced oxidation of the alpha and beta subunits in recombinant human hemoglobin.


    Organizational Affiliation

    Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77005-1892, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
MYOGLOBIN
A
154Physeter catodonMutation(s): 0 
Gene Names: MB
Find proteins for P02185 (Physeter catodon)
Go to Gene View: MB
Go to UniProtKB:  P02185
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

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Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
HEM
Query on HEM

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Download CCD File 
A
PROTOPORPHYRIN IX CONTAINING FE
HEME
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
ETN
Query on ETN

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Download CCD File 
A
METHYLETHYLAMINE
C3 H9 N
LIWAQLJGPBVORC-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.7 Å
  • R-Value Work: 0.159 
  • Space Group: P 6
Unit Cell:
Length (Å)Angle (°)
a = 91.622α = 90.00
b = 91.622β = 90.00
c = 45.963γ = 120.00
Software Package:
Software NamePurpose
X-PLORphasing
X-PLORrefinement
R-AXISdata reduction
R-AXISdata scaling
X-PLORmodel building

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1996-11-08
    Type: Initial release
  • Version 1.1: 2008-03-24
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance