2R2V

Sequence Determinants of the Topology of the Lac Repressor Tetrameric Coiled Coil


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.191 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Conformational specificity of the lac repressor coiled-coil tetramerization domain.

Liu, J.Zheng, Q.Deng, Y.Li, Q.Kallenbach, N.R.Lu, M.

(2007) Biochemistry 46: 14951-14959

  • DOI: 10.1021/bi701930d

  • PubMed Abstract: 
  • Predictive understanding of how the folded, functional shape of a native protein is encoded in the linear sequence of its amino acid residues remains an unsolved challenge in modern structural biology. Antiparallel four-stranded coiled coils are rela ...

    Predictive understanding of how the folded, functional shape of a native protein is encoded in the linear sequence of its amino acid residues remains an unsolved challenge in modern structural biology. Antiparallel four-stranded coiled coils are relatively simple protein structures that embody a heptad sequence repeat and rich diversity for tertiary packing of alpha-helices. To explore specific sequence determinants of the lac repressor coiled-coil tetramerization domain, we have engineered a set of buried nonpolar side chains at the a-, d-, and e-positions into the hydrophobic interior of the dimeric GCN4 leucine zipper. Circular dichroism and equilibrium ultracentrifugation studies show that this core variant (GCN4-pAeLV) forms a stable tetrameric structure with a reversible and highly cooperative thermal unfolding transition. The X-ray crystal structure at 1.9 A reveals that GCN4-pAeLV is an antiparallel four-stranded coiled coil of the lac repressor type in which the a, d, and e side chains associate by means of combined knobs-against-knobs and knobs-into-holes packing with a characteristic interhelical offset of 0.25 heptad. Comparison of the side chain shape and packing in the antiparallel tetramers shows that the burial of alanine residues at the e positions between the neighboring helices of GCN4-pAeLV dictates both the antiparallel orientation and helix offset. This study fills in a gap in our knowledge of the determinants of structural specificity in antiparallel coiled coils and improves our understanding of how specific side chain packing forms the teritiary structure of a functional protein.


    Organizational Affiliation

    Department of Biochemistry, Weill Medical College of Cornell University, New York, New York 10021, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
GCN4 leucine zipper
A, B, C, D, E, F, G, H
34N/AN/A
Protein Feature View is not available: No corresponding UniProt sequence found.
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN

Download SDF File 
Download CCD File 
C, D
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
CIT
Query on CIT

Download SDF File 
Download CCD File 
C, D, G
CITRIC ACID
C6 H8 O7
KRKNYBCHXYNGOX-UHFFFAOYSA-N
 Ligand Interaction
ACT
Query on ACT

Download SDF File 
Download CCD File 
C, D
ACETATE ION
C2 H3 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-M
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.191 
  • Space Group: P 43
Unit Cell:
Length (Å)Angle (°)
a = 51.696α = 90.00
b = 51.696β = 90.00
c = 99.793γ = 90.00
Software Package:
Software NamePurpose
DENZOdata reduction
PHASERphasing
ADSCdata collection
REFMACrefinement
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2007-08-27 
  • Released Date: 2008-06-17 
  • Deposition Author(s): Liu, J., Lu, M.

Revision History 

  • Version 1.0: 2008-06-17
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance