1MX6

Structure of p18INK4c (F92N)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.263 
  • R-Value Work: 0.237 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure-based design of p18INK4c proteins with increased thermodynamic stability and cell cycle inhibitory activity

Venkataramani, R.N.MacLachlan, T.K.Chai, X.El-Deiry, W.S.Marmorstein, R.

(2002) J.Biol.Chem. 277: 48827-48833

  • DOI: 10.1074/jbc.M208061200
  • Primary Citation of Related Structures:  1MX2, 1MX4

  • PubMed Abstract: 
  • p18(INK4c) is a member of the INK4 family of proteins that regulate the G(1) to S cell cycle transition by binding to and inhibiting the pRb kinase activity of cyclin-dependent kinases 4 and 6. The p16(INK4a) member of the INK4 protein family is alte ...

    p18(INK4c) is a member of the INK4 family of proteins that regulate the G(1) to S cell cycle transition by binding to and inhibiting the pRb kinase activity of cyclin-dependent kinases 4 and 6. The p16(INK4a) member of the INK4 protein family is altered in a variety of cancers and structure-function studies of the INK4 proteins reveal that the vast majority of missense tumor-derived p16(INK4a) mutations reduce protein thermodynamic stability. Based on this observation, we used p18(INK4c) as a model to test the proposal that INK4 proteins with increased stability might have enhanced cell cycle inhibitory activity. Structure-based mutagenesis was used to prepare p18(INK4c) mutant proteins with a predicted increase in stability. Using this approach, we report the generation of three mutant p18(INK4C) proteins, F71N, F82Q, and F92N, with increased stability toward thermal denaturation of which the F71N mutant also showed an increased stability to chemical denaturation. The x-ray crystal structures of the F71N, F82Q, and F92N p18INK4C mutant proteins were determined to reveal the structural basis for their increased stability properties. Significantly, the F71N mutant also showed enhanced CDK6 interaction and cell cycle inhibitory activity in vivo, as measured using co-immunoprecipitation and transient transfection assays, respectively. These studies show that a structure-based approach to increase the thermodynamic stability of INK4 proteins can be exploited to prepare more biologically active molecules with potential applications for the development of molecules to treat p16(INK4a)-mediated cancers.


    Organizational Affiliation

    The Wistar Institute, Philadelphia, Pennsylvania 19104, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Cyclin-dependent kinase 6 inhibitor
A, B
168Homo sapiensGene Names: CDKN2C (CDKN6)
Find proteins for P42773 (Homo sapiens)
Go to Gene View: CDKN2C
Go to UniProtKB:  P42773
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.263 
  • R-Value Work: 0.237 
  • Space Group: P 21 21 2
Unit Cell:
Length (Å)Angle (°)
a = 55.005α = 90.00
b = 150.843β = 90.00
c = 40.574γ = 90.00
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
CNSrefinement
CNSphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2002-10-16
    Type: Initial release
  • Version 1.1: 2008-04-28
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance