Studies on the structure and mechanism of H-ras p21.
Current knowledge of the structure of H-ras p21 is reviewed with particular emphasis on the interaction between guanine nucleotides and the active site of the protein. The nature of the conformational change induced by GTP hydrolysis is discussed. The major change is seen in the region known as the effector loop (loop 2), with significant but less well-defined changes occurring in loop 4, which is implicated in the GTPase reaction. Other evidence concerning the mechanism of GTP hydrolysis and its activation by GAP (GTPase-activating protein) is also discussed. Evidence regarding the rate limiting step in the p21 GTPase reaction, and the manner in which this and possibly other steps are accelerated by GAP, is inconclusive.
Abteilung Biophysik, Max-Planck-Institut für Medizinische Forschung, Heidelberg, F.R.G.
R S
RS
Goody
E F
EF
Pai
I
I
Schlichting
H
H
Rensland
A
A
Scheidig
S
S
Franken
A
A
Wittinghofer
D000595:Amino Acid Sequence; D001665:Binding Sites; D020690:GTPase-Activating Proteins; D006150:Guanine Nucleotides / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009154:Mutation; D015689:Oncogene Protein p21(ras) / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D020703:ras GTPase-Activating Proteins
D020690:GTPase-Activating Proteins; D006150:Guanine Nucleotides; D011506:Proteins; D020703:ras GTPase-Activating Proteins; D015689:Oncogene Protein p21(ras)