1MNI

ALTERATION OF AXIAL COORDINATION BY PROTEIN ENGINEERING IN MYOGLOBIN. BIS-IMIDAZOLE LIGATION IN THE HIS64-->VAL(SLASH)VAL68-->HIS DOUBLE MUTANT


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.07 Å

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Alteration of axial coordination by protein engineering in myoglobin. Bisimidazole ligation in the His64-->Val/Val68-->His double mutant.

Dou, Y.Admiraal, S.J.Ikeda-Saito, M.Krzywda, S.Wilkinson, A.J.Li, T.Olson, J.S.Prince, R.C.Pickering, I.J.George, G.N.

(1995) J.Biol.Chem. 270: 15993-16001


  • PubMed Abstract: 
  • Pig and human myoglobin have been engineered to reverse the positions of the distal histidine and valine (i.e. His64(E7)-->Val and Val68(E11)-->His). Spectroscopic and ligand binding properties have been measured for human and pig H64V/V68H myoglobin ...

    Pig and human myoglobin have been engineered to reverse the positions of the distal histidine and valine (i.e. His64(E7)-->Val and Val68(E11)-->His). Spectroscopic and ligand binding properties have been measured for human and pig H64V/V68H myoglobin, and the structure of the pig H64V/V68H double mutant has been determined to 2.07-A resolution by x-ray crystallography. The crystal structure shows that the N epsilon of His68 is located 2.3 A away from the heme iron, resulting in the formation of a hexacoordinate species. The imidazole plane of His68 is tilted relative to the heme normal; moreover it is not parallel to that of His93, in agreement with our previous proposal (Qin, J., La Mar, G. N., Dou, Y., Admiraal, S. J., and Ikeda-Saito, M. (1994) J. Biol. Chem. 269, 1083-1090). At cryogenic temperatures, the heme iron is in a low spin state, which exhibits a highly anisotropic EPR spectrum (g1 = 3.34, g2 = 2.0, and g3 < 1), quite different from that of the imidazole complex of metmyoglobin. The mean iron-nitrogen distance is 2.01 A for the low spin ferric state as determined by x-ray spectroscopy. The ferrous form of H64V/V68H myoglobin shows an optical spectrum that is similar to that of b-type cytochromes and consistent with the hexacoordinate bisimidazole hemin structure determined by the x-ray crystallography. The double mutation lowers the ferric/ferrous couple midpoint potential from +54 mV of the wild-type protein to -128 mV. Ferrous H64V/V68H myoglobin binds CO and NO to form stable complexes, but its reaction with O2 results in a rapid autooxidation to the ferric species. All of these results demonstrate that the three-dimensional positions of His64 and Val68 in the wild-type myoglobin are as important as the chemical nature of the side chains in facilitating reversible O2 binding and inhibiting autooxidation.


    Related Citations: 
    • Distal Pocket Polarity in Ligand Binding to Myoglobin: Deoxy and Carbonmonoxy Forms of Threonine68(E11) Mutant Investigated by X-Ray Crystallography and Infrared Spectroscopy
      Cameron, A.D.,Smerdon, S.J.,Wilkinson, A.J.,Habash, J.,Helliwell, J.R.,Li, T.,Olson, J.S.
      (1993) Biochemistry 32: 13061
    • High Resolution X-Ray Structures of Pig Metmyoglobin and Two Cd3 Mutants Mb(Lys45-->Arg) and Mb(Lys45-->Ser)
      Oldfield, T.J.,Smerdon, S.J.,Dauter, Z.,Petratos, K.,Wilson, K.S.,Wilkinson, A.J.
      (1992) Biochemistry 31: 8732
    • Determination of the Crystal Structure of Recombinant Pig Myoglobin by Molecular Replacement and its Refinement
      Smerdon, S.J.,Oldfield, T.J.,Dodson, E.J.,Dodson, G.G.,Hubbard, R.E.,Wilkinson, A.J.
      (1990) Acta Crystallogr.,Sect.B 46: 370


    Organizational Affiliation

    Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4970, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
MYOGLOBIN
A, B
153Sus scrofaMutation(s): 0 
Gene Names: MB
Find proteins for P02189 (Sus scrofa)
Go to Gene View: MB
Go to UniProtKB:  P02189
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM

Download SDF File 
Download CCD File 
A, B
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: 2.07 Å
  • Space Group: I 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 124.490α = 90.00
b = 42.280β = 92.62
c = 92.270γ = 90.00
Software Package:
Software NamePurpose
ARP/wARPmodel building
PROLSQrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1995-04-20
    Type: Initial release
  • Version 1.1: 2008-03-24
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance