1XZ1

Complex of halothane with apoferritin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.75 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.179 
  • R-Value Observed: 0.181 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Structural basis for high-affinity volatile anesthetic binding in a natural 4-helix bundle protein.

Liu, R.Loll, P.J.Eckenhoff, R.G.

(2005) FASEB J 19: 567-576

  • DOI: 10.1096/fj.04-3171com
  • Primary Citation of Related Structures:  
    1XZ1, 1XZ3

  • PubMed Abstract: 
  • Physiologic sites for inhaled anesthetics are presumed to be cavities within transmembrane 4-alpha-helix bundles of neurotransmitter receptors, but confirmation of binding and structural detail of such sites remains elusive. To provide such detail, we screened soluble proteins containing this structural motif, and found only one that exhibited evidence of strong anesthetic binding ...

    Physiologic sites for inhaled anesthetics are presumed to be cavities within transmembrane 4-alpha-helix bundles of neurotransmitter receptors, but confirmation of binding and structural detail of such sites remains elusive. To provide such detail, we screened soluble proteins containing this structural motif, and found only one that exhibited evidence of strong anesthetic binding. Ferritin is a 24-mer of 4-alpha-helix bundles; both halothane and isoflurane bind with K(A) values of approximately 10(5) M(-1), higher than any previously reported inhaled anesthetic-protein interaction. The crystal structures of the halothane/apoferritin and isoflurane/apoferritin complexes were determined at 1.75 A resolution, revealing a common anesthetic binding pocket within an interhelical dimerization interface. The high affinity is explained by several weak polar contacts and an optimal host/guest packing relationship. Neither the acidic protons nor ether oxygen of the anesthetics contribute to the binding interaction. Compared with unliganded apoferritin, the anesthetic produced no detectable alteration of structure or B factors. The remarkably high affinity of the anesthetic/apoferritin complex implies greater selectivity of protein sites than previously thought, and suggests that direct protein actions may underlie effects at lower than surgical levels of anesthetic, including loss of awareness.


    Organizational Affiliation

    Department of Anesthesia, University of Pennsylvania, Philadelphia, Pennsylvania, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Ferritin light chainA174Equus caballusMutation(s): 0 
Gene Names: FTL
UniProt
Find proteins for P02791 (Equus caballus)
Explore P02791 
Go to UniProtKB:  P02791
Protein Feature View
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  • Reference Sequence
Small Molecules
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
HLTKa:  100000   M^-1  Binding MOAD
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.75 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.179 
  • R-Value Observed: 0.181 
  • Space Group: F 4 3 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 181.61α = 90
b = 181.61β = 90
c = 181.61γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
MAR345data collection
d*TREKdata scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-05-10
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.3: 2017-10-11
    Changes: Refinement description