1IHB

CRYSTAL STRUCTURE OF P18-INK4C(INK6)

Summary for 1IHB

• Entry DOI: 10.2210/pdb1ihb/pdb
• Descriptor: CYCLIN-DEPENDENT KINASE 6 INHIBITOR (2 entities in total)
• Functional Keywords: cell cycle inhibitor, p18-ink4c(ink6), ankyrin repeat, cdk 4/6 inhibitor
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 2
• Total formula weight: 35129.47

Authors

Ravichandran, V.,Swaminathan, K.,Marmorstein, R. (deposition date: 1997-10-25, release date: 1998-12-02, Last modification date: 2024-02-07)

Primary citation

Venkataramani, R.,Swaminathan, K.,Marmorstein, R.
Crystal structure of the CDK4/6 inhibitory protein p18INK4c provides insights into ankyrin-like repeat structure/function and tumor-derived p16INK4 mutations.
Nat.Struct.Biol., 5:74-81, 1998

PubMed Abstract: p18INK4c is a member of a family of INK4 proteins that function to arrest the G1 to S cell cycle transition by inhibiting the activity of the cyclin-dependent kinases 4 and 6. The X-ray crystal structure of the human p18INK4c protein to a resolution of 1.95 A reveals an elongated molecule comprised of five contiguous 32- or 33-residue ankyrin-like repeat units. Each ankyrin-like repeat contains a beta-strand helix-turn-helix extended strand beta-strand motif that associates with neighboring motifs through beta-sheet, and helical bundle interactions. Conserved ankyrin-like repeat residues function to facilitate the ankyrin repeat fold and the tertiary interactions between neighboring repeat units. A large percentage of residues that are conserved among INK4 proteins and that map to positions of tumor-derived p16INK4 mutations play important roles in protein stability. A subset of these residues suggest an INK4 binding surface for the cyclin-dependent kinases 4 and 6. This surface is centered around a region that shows structural features uncharacteristic of ankyrin-like repeat units.

PubMed: 9437433
DOI: 10.1038/nsb0198-74

Experimental method

X-RAY DIFFRACTION (1.95 Å)