1MLU

NITRIC OXIDE RECOMBINATION TO DOUBLE MUTANTS OF MYOGLOBIN: THE ROLE OF LIGAND DIFFUSION IN A FLUCTUATING HEME POCKET


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Work: 0.143 
  • R-Value Observed: 0.143 

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Literature

Nitric oxide recombination to double mutants of myoglobin: role of ligand diffusion in a fluctuating heme pocket.

Carlson, M.L.Regan, R.Elber, R.Li, H.Phillips Jr., G.N.Olson, J.S.Gibson, Q.H.

(1994) Biochemistry 33: 10597-10606

  • DOI: https://doi.org/10.1021/bi00201a005
  • Primary Citation of Related Structures:  
    1MLU

  • PubMed Abstract: 

    Picosecond recombination of nitric oxide to the double mutants of myoglobin, His64Gly-Val68Ala and His64Gly.Val68Ile, at E7 and E11, has been studied experimentally and by computation. It is shown that distal residues have a profound effect on NO recombination. Recombination in the mutants may be explained in terms of fluctuating free volume and structure of the heme pocket. The double mutants provide insight into the effects of free volume and steric hindrance on rates of ligand rebinding following photolysis. Water molecules of the first solvation shell replace surface residues deleted by mutation and can block apparent holes in the protein structure. Thus, water molecules extend the time required for ligands to escape significantly to a nanosecond time scale, which is much longer than would be expected for an open heme pocket. Both nearly exponential (G64A68) and markedly nonexponential (native and G64I68) kinetics are observed, a result at variance with expectation from the model of Petrich et al. [Petrich, J.W., Lambry, J.C., Kuczera, K., Karplus, M., Poyart, C., & Martin, J.L. (1991) Biochemistry 30, 3975-3987], which attributes nonexponential kinetics to proximal effects.


  • Organizational Affiliation

    Department of Biochemistry, Molecular and Cell Biology, Cornell University Ithaca, New York 14853.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
MYOGLOBIN154Physeter catodonMutation(s): 0 
UniProt
Find proteins for P02185 (Physeter macrocephalus)
Explore P02185 
Go to UniProtKB:  P02185
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP02185
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Work: 0.143 
  • R-Value Observed: 0.143 
  • Space Group: P 6
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 91.2α = 90
b = 91.2β = 90
c = 45.87γ = 120
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
X-PLORphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1994-08-31
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2024-02-14
    Changes: Data collection, Database references, Derived calculations, Other