Macromolecule Content

• Total Structure Weight: 18.15 kDa 
• Atom Count: 1275 
• Residue Count: 168 
• Unique protein chains: 1

1BU9

SOLUTION STRUCTURE OF P18-INK4C, 21 STRUCTURES

• DOI: 10.2210/pdb1BU9/pdb

• Classification: HORMONE/GROWTH FACTOR
• Organism(s): Homo sapiens
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 1998-09-15 Released: 1999-09-13 
• Deposition Author(s): Byeon, I.-J.L., Li, J., Tsai, M.-D.

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Experimental Data Snapshot

• Method: SOLUTION NMR
• Conformers Calculated: 50 
• Conformers Submitted: 21 
• Selection Criteria: CLOSEST TO MEAN STRUCTURE WHICH SHOWS GOOD AGREEMENT WITH THE CONSTRAINTS 

Literature

Tumor suppressor INK4: determination of the solution structure of p18INK4C and demonstration of the functional significance of loops in p18INK4C and p16INK4A.

Li, J., Byeon, I.J., Ericson, K., Poi, M.J., O'Maille, P., Selby, T., Tsai, M.D.

(1999) Biochemistry 38: 2930-2940

• PubMed: 10074345 
• DOI: 10.1021/bi982286e
• Primary Citation of Related Structures:  
  1BU9


• PubMed Abstract: 
  

Since the structures of several ankyrin-repeat proteins including the INK4 (inhibitor of cyclin-dependent kinase 4) family have been reported recently, the detailed structures and the functional roles of the loops have drawn considerable interest. This paper addresses the potential importance of the loops of ankyrin-repeat proteins in three aspects. First, the solution structure of p18INK4C was determined by NMR, and the loop structures were analyzed in detail. The loops adapt nascent antiparallel beta-sheet structures, but the positions are slightly different from those in the crystal structure. A detailed comparison between the solution structures of p16 and p18 has also been presented. The determination of the p18 solution structure made such detailed comparisons possible for the first time. Second, the [1H,15N]HSQC NMR experiment was used to probe the interactions between p18INK4C and other proteins. The results suggest that p18INK4C interacts very weakly with dna K and glutathione S-transferase via the loops. The third aspect employed site-specific mutagenesis and functional assays. Three mutants of p18 and 11 mutants of p16 were constructed to test functional importance of loops and helices. The results suggest that loop 2 is likely to be part of the recognition surface of p18INK4C or p16INK4A for CDK4, and they provide quantitative functional contributions of specific residues. Overall, our results enhance understanding of the structural and functional roles of the loops in INK4 tumor suppressors in particular and in ankyrin-repeat proteins in general.

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Organizational Affiliation: 

Department of Chemistry, Campus Chemical Instrument Center, The Ohio State University, Columbus 43210, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
PROTEIN (CYCLIN-DEPENDENT KINASE 6 INHIBITOR)	A	168	Homo sapiens	Mutation(s): 0  Gene Names: CDKN2C, CDKN6
Find proteins for P42773 (Homo sapiens) Explore P42773  Go to UniProtKB:  P42773
NIH Common Fund Data Resources
PHAROS  P42773 GTEx  ENSG00000123080

Experimental Data & Validation

Experimental Data

• Method: SOLUTION NMR
• Conformers Calculated: 50 
• Conformers Submitted: 21 
• Selection Criteria: CLOSEST TO MEAN STRUCTURE WHICH SHOWS GOOD AGREEMENT WITH THE CONSTRAINTS 
• OLDERADO: 1BU9 Olderado

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 1998-09-15 
• Released Date: 1999-09-13 
Deposition Author(s): Byeon, I.-J.L., Li, J., Tsai, M.-D.

Revision History 

• Version 1.0: 1999-09-13
  Type: Initial release
  
• Version 1.1: 2008-04-27
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance