1MYM

STRUCTURAL DETERMINANTS OF CO STRETCHING VIBRATION FREQUENCIES IN MYOGLOBIN


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

Structural determinants of the stretching frequency of CO bound to myoglobin.

Li, T.Quillin, M.L.Phillips Jr., G.N.Olson, J.S.

(1994) Biochemistry 33: 1433-1446


  • PubMed Abstract: 
  • In order to assess the relative importance of polar versus steric interactions, infrared spectra and overall CO binding properties were measured at room temperature for 41 different recombinant myoglobins containing mutations at His64(E7), Val68(E11) ...

    In order to assess the relative importance of polar versus steric interactions, infrared spectra and overall CO binding properties were measured at room temperature for 41 different recombinant myoglobins containing mutations at His64(E7), Val68(E11), Phe43(CD1), Arg45(CD3), Phe46(CD4), and Leu29(B10). The results were compared to the crystal structures of wild-type, Phe29, Val46, Ala68, Phe68, Gln64, Leu64, and Gly64 sperm whale CO-myoglobin and that of Thr68 pig CO-myoglobin. As observed in several previous studies, replacement of the distal histidine (His64) with aliphatic amino acids results in the appearance of a single IR band in the 1960-1970-cm-1 region and in large increases in CO affinity (KCO). More complex behavior is observed for Gly, Ala, Gln, Met, and Trp substitutions at position 64, but in each case there is a net increase in the intensity of this high-frequency component. Replacement of Val68 with Ala, Leu, Ile, and Phe produces little effect on the IR spectrum, whereas these mutations cause 20-fold changes in KCO, presumably due to steric effects. Replacement of Val68 with Thr decreases KCO 4-5-fold, whereas the position of the major IR band increases from 1945 to 1961 cm-1. Replacement of Val68 with Asn also causes a large decrease in KCO, but in this case, the peak position of the major IR band decreases from 1945 to 1916 cm-1. Nine replacements were made in the CD corner at positions 43, 45, and 46. All of the resultant mutants show increased stretching frequencies that can be correlated with movement of the imidazole side chain of His64 away from the bound ligand. All five substitutions at position 29 cause changes in the IR spectra. The Leu29-->Phe mutation had the largest effect, producing a single band centered at 1932 cm-1. Together these data demonstrate that there is little direct correlation between affinity, vCO, and Fe-C-O geometry. The major factor governing vCO appears to be the electrostatic potential surrounding the bound ligand and not steric hindrance. The presence of positive charges from proton donors, such as N epsilon of His64 and N delta of Asn68, cause a decrease in the bond order and stretching frequency of bound CO. In contrast, the negative portion of the Thr68 dipole points directly toward the bound ligand and increases the C-O bond order and stretching frequency. Movement of His64 away from the bound ligand or replacement of this residue with aliphatic amino acids prevents hydrogen-bonding interactions, causing vCO to increase.(ABSTRACT TRUNCATED AT 250 WORDS)


    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-Level Expression of Sperm Whale Myoglobin in Escherichia Coli
      Springer, B.A.,Sligar, S.G.
      (1987) Proc.Natl.Acad.Sci.USA 84: 8961
    • 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 --: --


    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
MYOGLOBIN
A
154Physeter macrocephalusMutation(s): 0 
Gene Names: MB
Find proteins for P02185 (Physeter macrocephalus)
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
CMO
Query on CMO

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Download CCD File 
A
CARBON MONOXIDE
C O
UGFAIRIUMAVXCW-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 = 91.370α = 90.00
b = 91.370β = 90.00
c = 45.930γ = 120.00
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORphasing
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