1CDJ

STRUCTURE OF T-CELL SURFACE GLYCOPROTEIN CD4


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Work: 0.189 
  • R-Value Observed: 0.189 

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This is version 1.2 of the entry. See complete history


Literature

Kinetic and structural analysis of mutant CD4 receptors that are defective in HIV gp120 binding.

Wu, H.Myszka, D.G.Tendian, S.W.Brouillette, C.G.Sweet, R.W.Chaiken, I.M.Hendrickson, W.A.

(1996) Proc Natl Acad Sci U S A 93: 15030-15035

  • DOI: 10.1073/pnas.93.26.15030
  • Primary Citation of Related Structures:  
    1CDJ, 1CDY, 1CDU

  • PubMed Abstract: 
  • The T-cell antigen coreceptor CD4 also serves as the receptor for the envelope glycoprotein gp120 of HIV. Extensive mutational analysis of CD4 has implicated residues from a portion of the extracellular amino-terminal domain (D1) in gp120 binding. However, none of these proteins has been fully characterized biophysically, and thus the precise effects on molecular structure and binding interactions are unknown ...

    The T-cell antigen coreceptor CD4 also serves as the receptor for the envelope glycoprotein gp120 of HIV. Extensive mutational analysis of CD4 has implicated residues from a portion of the extracellular amino-terminal domain (D1) in gp120 binding. However, none of these proteins has been fully characterized biophysically, and thus the precise effects on molecular structure and binding interactions are unknown. In the present study, we produced soluble versions of three mutant CD4 molecules (F43V, G47S, and A55F) and characterized their structural properties, thermostability, and ability to bind gp120. Crystallographic and thermodynamic analysis showed minimal structural alterations in the F43V and G47S mutant proteins, which have solvent-exposed mutant side chains. In contrast, some degree of disorder appears to exist in the folded state of A55F, as a result of mutating a buried side chain. Real time kinetic measurements of the interaction of the mutant proteins with gp120 showed affinity decreases of 5-fold for G47S, 50-fold for A55F, and 200-fold for F43V. Although both rate constants for the binding reaction were affected by these mutations, the loss in affinity was mainly due to a decrease in on rates, with less drastic changes occurring in the off rates. These observations suggest the involvement of conformational adaptation in the CD4-gp120 interaction. Together, the structural and kinetic data confirm that F43V is a critical residue in gp120 recognition site, which may also include main chain interactions at residue Gly-47.


    Organizational Affiliation

    Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
T-CELL SURFACE GLYCOPROTEIN CD4A178Homo sapiensMutation(s): 0 
Gene Names: CD4
UniProt & NIH Common Fund Data Resources
Find proteins for P01730 (Homo sapiens)
Explore P01730 
Go to UniProtKB:  P01730
PHAROS:  P01730
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Work: 0.189 
  • R-Value Observed: 0.189 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 82.7α = 90
b = 30.4β = 117.3
c = 87.7γ = 90
Software Package:
Software NamePurpose
X-PLORrefinement

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1997-04-01
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance