title: Comparison of the predicted structure for the activated form of the P21 protein with the X-ray crystal structure.
abstract: The predicted conformation and position of the central transforming region (residues 55-67) of the p21 protein are compared with the conformation and position of this segment in a recently determined X-ray crystal structure of residues 1-166 of this protein in the activated state bound to a nonhydrolyzable GTP derivative. We previously predicted that this segment of the protein would adopt a roughly extended conformation from Ile 55-Thr 58, a reverse turn at Ala 59-Gln 61, followed by an alpha-helix from Glu 62-Met 67. We further predicted that this region of the activated protein occupies a position that is virtually identical to corresponding regions in the homologous purine nucleotide-binding proteins, bacterial elongation factor (EF-tu), and adenylate kinase (ADK). We find that there is a close correspondence between the conformation and position of our predicted structure and those found in the X-ray crystal structure. A mechanism for activation of the protein is proposed and is corroborated by X-ray crystallographic data.
authors.affiliation: Department of Chemistry, New York University, New York 10003.
authors.forename: J M
authors.initials: JM
authors.lastname: Chen
authors.forename: G
authors.initials: G
authors.lastname: Lee
authors.forename: P W
authors.initials: PW
authors.lastname: Brandt-Rauf
authors.forename: R B
authors.initials: RB
authors.lastname: Murphy
authors.forename: S
authors.initials: S
authors.lastname: Rackovsky
authors.forename: M R
authors.initials: MR
authors.lastname: Pincus
mesh_terms: D003198:Computer Simulation; D008956:Models, Chemical; D011487:Protein Conformation; D016283:Proto-Oncogene Proteins p21(ras) / Q000737:chemistry* / Q000378:metabolism; D014961:X-Ray Diffraction
chemical_list: D016283:Proto-Oncogene Proteins p21(ras)