1MGN

HIS64(E7)-> TYR APOMYOGLOBIN AS A REAGENT FOR MEASURING RATES OF HEMIN DISSOCIATION


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Work: 0.153 

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Literature

His64(E7)-->Tyr apomyoglobin as a reagent for measuring rates of hemin dissociation.

Hargrove, M.S.Singleton, E.W.Quillin, M.L.Ortiz, L.A.Phillips Jr., G.N.Olson, J.S.Mathews, A.J.

(1994) J.Biol.Chem. 269: 4207-4214


  • PubMed Abstract: 
  • To develop an assay for hemin dissociation, His64(E7) was replaced by Tyr in sperm whale myoglobin producing a holoprotein with a distinct green color due to an intense absorption band at 600 nm. Val68(E11) was replaced by Phe in the same protein to ...

    To develop an assay for hemin dissociation, His64(E7) was replaced by Tyr in sperm whale myoglobin producing a holoprotein with a distinct green color due to an intense absorption band at 600 nm. Val68(E11) was replaced by Phe in the same protein to increase its stability. When excess Tyr64-Val68 apoglobin is mixed with either metmyoglobin or methemoglobin, the solution turns from brown to green, and the absorbance changes can be used to measure complete time courses for hemin dissociation from either holoprotein. This assay has been used to measure rates of hemin dissociation from native metmyoglobin, four myoglobin mutants (Ala64(E7), Ala68(E11), Phe68(E11), and Glu45(CD3)), native methemoglobin, valence hybrid hemoglobins, and two mutant hemoglobins ((alpha(Gly-E7)beta(native))2, and (alpha(native)beta(Gly-E7))2). Two kinetic phases were observed for hemin dissociation from native human hemoglobin at pH 7.0 and 37 degrees C. Valence and mutant hybrid hemoglobins were used to assign the faster phase (k = 7.8 +/- 2.0 h-1) to hemin dissociation from ferric beta subunits and the slower (k = 0.6 +/- 0.15 h-1) to dissociation from alpha subunits. The corresponding rate for wild-type metmyoglobin is 0.007 +/- 0.004 h-1.


    Related Citations: 
    • Crystal Structure of Myoglobin from a Synthetic Gene
      Phillips Jr., G.N.,Arduini, R.M.,Springer, B.A.,Sligar, S.G.
      (1990) Proteins 7: 358
    • High Resolution Crystal Structures of Five Distal Histidine Mutants of Sperm Whale Myoglobin
      Quillin, M.L.,Arduini, R.M.,Olson, J.S.,Phillips Jr., G.N.
      () TO BE PUBLISHED --: --
    • High-Level Expression of Sperm Whale Myoglobin in Escherichia Coli
      Springer, B.A.,Sligar, S.G.
      (1987) Proc.Natl.Acad.Sci.USA 84: 8961


    Organizational Affiliation

    Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77251-1892.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
METMYOGLOBIN
A
154Physeter catodonGene Names: MB
Find proteins for P02185 (Physeter catodon)
Go to Gene View: MB
Go to UniProtKB:  P02185
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

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

Download SDF File 
Download CCD File 
A
PROTOPORPHYRIN IX CONTAINING FE
HEME
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Work: 0.153 
  • Space Group: P 6
Unit Cell:
Length (Å)Angle (°)
a = 91.200α = 90.00
b = 91.200β = 90.00
c = 45.870γ = 120.00
Software Package:
Software NamePurpose
X-PLORphasing
X-PLORmodel building
X-PLORrefinement

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1994-01-31
    Type: Initial release
  • Version 1.1: 2008-03-24
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance