Comparison of the conformation and GTP hydrolysing ability of N-terminal ras p21 protein segments.
Conformational, GTP binding, and GTP hydrolytic studies are carried out with synthetically prepared N-terminal 34 residue segments (residues 2-35) of p21 ras oncogenic (12-Val) and non-oncogenic (12-Gly) proteins. It was found that these N-terminal regions bind nucleotides through their phosphate groups, and that substitution of valine for glycine produces a more pronounced alpha-helical structure and decreases the conformational flexibility. The glycine containing peptide, when compared to the valine containing analog, catalyses the hydrolysis of GTP 6 times more efficiently. Results suggest that restriction of conformational adaptation may contribute to the transforming capacity of the Val-12 p21 protein.
Niu
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Division of Metabolism and Endocrine Drug Products, FDA, Rockville, MD 20852.
Han
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Roller
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PP
D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D002471:Cell Transformation, Neoplastic; D002942:Circular Dichroism; D005998:Glycine; D006160:Guanosine Triphosphate / Q000378:metabolism*; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D015689:Oncogene Protein p21(ras); D009856:Oncogene Proteins, Viral / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism*; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D014633:Valine
D009363:Neoplasm Proteins; D009856:Oncogene Proteins, Viral; D010446:Peptide Fragments; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D015689:Oncogene Protein p21(ras); D014633:Valine; D005998:Glycine