4IMY

The AFF4 scaffold binds human P-TEFb adjacent to HIV Tat


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.94 Å
  • R-Value Free: 0.245 
  • R-Value Work: 0.207 
  • R-Value Observed: 0.209 

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Ligand Structure Quality Assessment 


This is version 1.2 of the entry. See complete history


Literature

The AFF4 scaffold binds human P-TEFb adjacent to HIV Tat.

Schulze-Gahmen, U.Upton, H.Birnberg, A.Bao, K.Chou, S.Krogan, N.J.Zhou, Q.Alber, T.

(2013) Elife 2: e00327-e00327

  • DOI: https://doi.org/10.7554/eLife.00327
  • Primary Citation of Related Structures:  
    4IMY

  • PubMed Abstract: 

    Human positive transcription elongation factor b (P-TEFb) phosphorylates RNA polymerase II and regulatory proteins to trigger elongation of many gene transcripts. The HIV-1 Tat protein selectively recruits P-TEFb as part of a super elongation complex (SEC) organized on a flexible AFF1 or AFF4 scaffold. To understand this specificity and determine if scaffold binding alters P-TEFb conformation, we determined the structure of a tripartite complex containing the recognition regions of P-TEFb and AFF4. AFF4 meanders over the surface of the P-TEFb cyclin T1 (CycT1) subunit but makes no stable contacts with the CDK9 kinase subunit. Interface mutations reduced CycT1 binding and AFF4-dependent transcription. AFF4 is positioned to make unexpected direct contacts with HIV Tat, and Tat enhances P-TEFb affinity for AFF4. These studies define the mechanism of scaffold recognition by P-TEFb and reveal an unanticipated intersubunit pocket on the AFF4 SEC that potentially represents a target for therapeutic intervention against HIV/AIDS. DOI:http://dx.doi.org/10.7554/eLife.00327.001.


  • Organizational Affiliation

    Department of Molecular and Cell Biology , University of California, Berkeley , Berkeley , United States.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Cyclin-dependent kinase 9
A, C, E
332Homo sapiensMutation(s): 0 
Gene Names: CDK9CDC2L4TAK
EC: 2.7.11.22 (PDB Primary Data), 2.7.11.23 (PDB Primary Data)
UniProt & NIH Common Fund Data Resources
Find proteins for P50750 (Homo sapiens)
Explore P50750 
Go to UniProtKB:  P50750
PHAROS:  P50750
GTEx:  ENSG00000136807 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP50750
Sequence Annotations
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  • Reference Sequence
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
Cyclin-T1
B, D, F
264Homo sapiensMutation(s): 0 
Gene Names: CCNT1
UniProt & NIH Common Fund Data Resources
Find proteins for O60563 (Homo sapiens)
Explore O60563 
Go to UniProtKB:  O60563
PHAROS:  O60563
GTEx:  ENSG00000129315 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO60563
Sequence Annotations
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  • Reference Sequence
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Entity ID: 3
MoleculeChains Sequence LengthOrganismDetailsImage
AF4/FMR2 family member 4
G, H, I
75Homo sapiensMutation(s): 0 
Gene Names: AFF4AF5Q31MCEFHSPC092
UniProt & NIH Common Fund Data Resources
Find proteins for Q9UHB7 (Homo sapiens)
Explore Q9UHB7 
Go to UniProtKB:  Q9UHB7
PHAROS:  Q9UHB7
GTEx:  ENSG00000072364 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9UHB7
Sequence Annotations
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  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
TPO
Query on TPO
A, C, E
L-PEPTIDE LINKINGC4 H10 N O6 PTHR
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.94 Å
  • R-Value Free: 0.245 
  • R-Value Work: 0.207 
  • R-Value Observed: 0.209 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 100.691α = 90
b = 126.298β = 90
c = 195.626γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
PHASERphasing
PHENIXrefinement
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-03-13
    Type: Initial release
  • Version 1.1: 2013-04-03
    Changes: Database references
  • Version 1.2: 2023-09-20
    Changes: Data collection, Database references, Derived calculations, Refinement description