1IRC

CYSTEINE RICH INTESTINAL PROTEIN


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.17 Å

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Replacement of the proximal ligand of sperm whale myoglobin with free imidazole in the mutant His-93-->Gly.

Barrick, D.

(1994) Biochemistry 33: 6546-6554


  • PubMed Abstract: 
  • The proximal bond between the iron atom of the heme group and the N epsilon of histidine F8 in myoglobin (Mb) and hemoglobin (Hb) is presumed to be an important determinant of heme binding, protein structure, and oxygen binding. Here a system is desc ...

    The proximal bond between the iron atom of the heme group and the N epsilon of histidine F8 in myoglobin (Mb) and hemoglobin (Hb) is presumed to be an important determinant of heme binding, protein structure, and oxygen binding. Here a system is described in which the proximal ligand is provided intermolecularly by the histidine side chain mimic imidazole. The proximal ligand of sperm whale Mb is replaced with glycine (H93G) using site-directed mutagenesis. The addition of imidazole to Escherichia coli expressing this gene reconstitutes myoglobin function. H93G Mb purified in the presence of imidazole is spectroscopically similar to wild-type Mb in combination with a wide variety of distal ligands. The crystal structure of H93G Mb, determined in the presence of imidazole, reveals that an imidazole molecule is bonded to the heme iron on the proximal side, substituting in trans for the side-chain function of the proximal histidine of wild-type Mb. Although H93G Mb is similar in spectroscopic and gross structural detail to wild-type Mb, subtle differences exist in the orientation of imidazole with respect to the heme group. trans-Complementation of proximal ligand function will allow the proximal bond in hemoproteins to be chemically substituted beyond the limits of the genetic code.


    Related Citations: 
    • Replacement of the Proximal Ligand of Sperm Whale Myoglobin with Free Imidazole in the Mutant His-93-->Gly
      Barrick, D.
      (1994) Biochemistry 33: 6546


    Organizational Affiliation

    Institute of Molecular Biology, University of Oregon, Eugene 97403.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
MYOGLOBIN (METAQUO)
A
154Physeter catodonMutation(s): 1 
Gene 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
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
IMD
Query on IMD

Download SDF File 
Download CCD File 
A
IMIDAZOLE
C3 H5 N2
RAXXELZNTBOGNW-UHFFFAOYSA-O
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.17 Å
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 40.150α = 90.00
b = 49.040β = 90.00
c = 79.140γ = 90.00
Software Package:
Software NamePurpose
SDMSdata reduction
TNTrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

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