title: Time-resolved X-ray crystallographic study of the conformational change in Ha-Ras p21 protein on GTP hydrolysis.
abstract: Crystals of Ha-Ras p21 with caged GTP at the active site have been used to investigate the conformational changes of p21 on GTP hydrolysis. The structure of the short-lived p21.GTP complex was determined by Laue diffraction methods. After GTP hydrolysis, substantial structural changes occur in the parts of the molecule implicated in the interaction with GTPase-activating protein. The trigger for this process seems to be a change in coordination of the active-site Mg2+ ion as a result of loss of the gamma-phosphate of GTP.
authors.affiliation: Abteilung Biophysik, Max-Planck-Institut für Medizinische Forschung, Heidelberg, FRG.
authors.forename: I
authors.initials: I
authors.lastname: Schlichting
authors.forename: S C
authors.initials: SC
authors.lastname: Almo
authors.forename: G
authors.initials: G
authors.lastname: Rapp
authors.forename: K
authors.initials: K
authors.lastname: Wilson
authors.forename: K
authors.initials: K
authors.lastname: Petratos
authors.forename: A
authors.initials: A
authors.lastname: Lentfer
authors.forename: A
authors.initials: A
authors.lastname: Wittinghofer
authors.forename: W
authors.initials: W
authors.lastname: Kabsch
authors.forename: E F
authors.initials: EF
authors.lastname: Pai
authors.forename: G A
authors.initials: GA
authors.lastname: Petsko
mesh_terms: D001665:Binding Sites; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003460:Crystallization; D020558:GTP Phosphohydrolases / Q000378:metabolism; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism*; D006165:Guanylyl Imidodiphosphate / Q000378:metabolism; D006868:Hydrolysis; D008239:Lysine; D008274:Magnesium / Q000378:metabolism; D008958:Models, Molecular; D015394:Molecular Structure; D010710:Phosphates / Q000378:metabolism; D010782:Photolysis; D011487:Protein Conformation; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D016283:Proto-Oncogene Proteins p21(ras); D014961:X-Ray Diffraction
chemical_list: D010710:Phosphates; D011518:Proto-Oncogene Proteins; D006153:Guanosine Diphosphate; D006165:Guanylyl Imidodiphosphate; D006160:Guanosine Triphosphate; D020558:GTP Phosphohydrolases; D016283:Proto-Oncogene Proteins p21(ras); D008274:Magnesium; D008239:Lysine