TUMOR SUPPRESSOR P15(INK4B) STRUCTURE BY COMPARATIVE MODELING AND NMR DATA
Tumor suppressor INK4: comparisons of conformational properties between p16(INK4A) and p18(INK4C).
GSPGIHMLGGSSDAGLATAAARGQVETVRQLLEAGADPNALNRFGRRPIQVMMMGSAQVAELLLLHGAEPNCADPATLTR PVHDAAREGFLDTLVVLHRAGARLDVCDAWGRLPVDLAEEQGHRDIARYLHAATGD
TRIPLE-RESONANCE NMR SPECTROSCOPY WAS USED TO DETERMINE THE P15 STRUCTURE
STRUCTURES WITH THE LEAST RESTRAINT VIOLATIONS, STRUCTURES WITH THE LOWEST ENERGY
DUE TO THE STRUCTURAL FLEXIBILITY AND INSTABILITY OF P15, ONLY A LIMITED NUMBER OF NMR CONSTRAINTS WERE COLLECTED. BECAUSE P15 SHARES MORE THAN 85% SEQUENCE HOMOLOGY WITH P16, 19 P15 STRUCTURES WERE GENERATED BY USING COMPARATIVE MODELING (MODELLER-4) WITH AN ENSEMBLE OF P16(INK4A) NMR STRUCTURES AS TEMPLATES. THE MODELING STRUCTURES WERE THEN SUBJECTED TO 1400 STEPS OF RESTRAINT ENERGY MINIMIZATION (X-PLOR) WITH THE NMR DATA (672 DISTANCE CONSTRAINTS). THE STRUCTURES THAT SATISFY THE NMR CONSTRAINTS WERE PICKED TO REPRESENT P15(INK4B).
COMPARATIVE MODELING, RESTRAINT ENERGY MINIMIZATION
0.2 MM P15, U-15N; 4 MM HEPES, 1 MM DTT, 5 UM EDTA
0.2 MM P15, U-15N,13C; 4 MM HEPES, 1 MM DTT, 5 UM EDTA
HELIX-TURN-HELIX, ANKYRIN REPEAT, SIGNALING PROTEIN