2GD7

The Structure of the Cyclin T-binding domain of Hexim1 reveals the molecular basis for regulation of transcription elongation


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure of the Cyclin T binding domain of Hexim1 and molecular basis for its recognition of P-TEFb.

Dames, S.A.Schonichen, A.Schulte, A.Barboric, M.Peterlin, B.M.Grzesiek, S.Geyer, M.

(2007) Proc.Natl.Acad.Sci.Usa 104: 14312-14317

  • DOI: 10.1073/pnas.0701848104

  • PubMed Abstract: 
  • Hexim1 is a cellular protein that associates with the positive transcription elongation factor b (P-TEFb) to regulate RNA polymerase II elongation of nascent mRNA transcripts. It directly binds to Cyclin T1 of P-TEFb and inhibits the kinase activity ...

    Hexim1 is a cellular protein that associates with the positive transcription elongation factor b (P-TEFb) to regulate RNA polymerase II elongation of nascent mRNA transcripts. It directly binds to Cyclin T1 of P-TEFb and inhibits the kinase activity of Cdk9, leading to an arrest of transcription elongation. Here, we report the solution structure of the Cyclin T binding domain (TBD) of Hexim1 that forms a parallel coiled-coil homodimer composed of two segments and a preceding alpha helix that folds back onto the first coiled-coil unit. NMR titration, fluorescence, and immunoprecipitation experiments revealed the binding interface to Cyclin T1, which covers a large surface on the first coiled-coil segment. Electrostatic interactions between an acidic patch on Hexim1 and positively charged residues of Cyclin T1 drive the complex formation that is confirmed by mutagenesis data on Hexim1 mediated transcription regulation in cells. Thus, our studies provide structural insights how Hexim1 recognizes the Cyclin T1 subunit of P-TEFb, which is a key step toward the regulation of transcription elongation.


    Related Citations: 
    • NMR assignment of the Cyclin T-binding domain of human Hexim1
      Dames, S.A.,Schoenichen, A.,Schulte, A.,Barboic, M.,Peterlin, M.,Grzesiek, S.,Geyer, M.
      () TO BE PUBLISHED --: --


    Organizational Affiliation

    Department of Structural Biology, Biozentrum Basel, University of Basel, 4003 Basel, Switzerland. sonja.dames@unibas.ch




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
HEXIM1 protein
A, B
107Homo sapiensMutation(s): 1 
Gene Names: HEXIM1 (CLP1, EDG1, HIS1, MAQ1)
Find proteins for O94992 (Homo sapiens)
Go to Gene View: HEXIM1
Go to UniProtKB:  O94992
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 
  • Olderado: 2GD7 Olderado

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2006-03-15 
  • Released Date: 2007-06-12 
  • Deposition Author(s): Dames, S.A.

Revision History 

  • Version 1.0: 2007-06-12
    Type: Initial release
  • Version 1.1: 2007-09-17
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance