1NXF

Ligand-linked transitions of deoxyHbI crystals exposed to CO.


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.189 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Ligand-linked structural transitions in crystals of a cooperative dimeric hemoglobin.

Knapp, J.E.Royer Jr., W.E.

(2003) Biochemistry 42: 4640-4647

  • DOI: 10.1021/bi027136p
  • Primary Citation of Related Structures:  1NWI, 1NWN

  • PubMed Abstract: 
  • Cooperative ligand binding in the dimeric hemoglobin (HbI) from the blood clam Scapharca inaequivalvis is mediated primarily by tertiary structural changes, but with a small quaternary rearrangement (approximately 3 degrees), based on analysis of dis ...

    Cooperative ligand binding in the dimeric hemoglobin (HbI) from the blood clam Scapharca inaequivalvis is mediated primarily by tertiary structural changes, but with a small quaternary rearrangement (approximately 3 degrees), based on analysis of distinct crystal forms for ligated and unligated molecules. We report here ligand transition structures in both crystal forms. Binding CO to unligated HbI crystals results in a structure that approaches, but does not attain, the full allosteric transition. In contrast, removing CO from the HbI-CO crystals results in a structure that possesses all the key low affinity attributes previously identified from analysis of HbI crystals grown in the unligated state. Subsequent binding of CO shows the reversibility of this process. The observed structural changes include the quaternary rearrangement even under the constraints of lattice interactions, demonstrating that subunit rotation is an integral component of the ligand-linked structural transition in HbI. Analysis of both crystal forms, along with data from HbI mutants, suggests that the quaternary structural change is linked to the movement of the heme group, supporting a hypothesis that the heme movement is the central event that triggers cooperative ligand binding in this hemoglobin dimer. These results show both the effects of a crystal lattice in limiting quaternary structural transitions and provide the first example of complete allosteric transitions within another crystal lattice.


    Related Citations: 
    • High resolution crystallographic analysis of a co-operative dimeric hemoglobin
      Royer JR., W.E.
      (1994) J.Mol.Biol. 235: 657


    Organizational Affiliation

    Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Globin I
A, B
146Anadara inaequivalvisN/A
Find proteins for P02213 (Anadara inaequivalvis)
Go to UniProtKB:  P02213
Small Molecules
Ligands 2 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
CMO
Query on CMO

Download SDF File 
Download CCD File 
A, B
CARBON MONOXIDE
C O
UGFAIRIUMAVXCW-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.189 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 92.040α = 90.00
b = 44.280β = 90.00
c = 144.030γ = 90.00
Software Package:
Software NamePurpose
CNSphasing
CNSrefinement
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-08-26
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-10-11
    Type: Refinement description