Dynamic polymorphism of Ras observed by single molecule FRET is the basis for molecular recognition.
Ras regulates signal transduction pathway function by dynamically interacting with various effectors. To understand the basis for Ras function, its conformational dynamics were measured in the absence and presence of effectors using single molecule fluorescence resonance energy transfer (FRET) between probes located on the Switch II region and GTP. The time trajectories of FRET efficiency from GTP-bound Ras showed that this conformation spontaneously varies among multiple states. Among them, a low FRET state was identified as an inactive state. The transition involving the inactive conformational state occurred in the time range of seconds. In contrast, fluctuation occurring most probably between multiple active high FRET conformational states lasted approximately 30 ms but converged to a specific conformational state upon binding to an effector. Thus, Ras conformation spontaneously fluctuates to readily interact with various effectors.
Department of Systems and Human Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka 560-9531, Japan.
Yoshiyuki
Y
Arai
Atsuko Hikikoshi
AH
Iwane
Tetsuichi
T
Wazawa
Hiroaki
H
Yokota
Yoshiharu
Y
Ishii
Tohru
T
Kataoka
Toshio
T
Yanagida
D031541:Fluorescence Resonance Energy Transfer / Q000379:methods; D005456:Fluorescent Dyes / Q000737:chemistry; D006160:Guanosine Triphosphate / Q000378:metabolism; D009154:Mutation; D011487:Protein Conformation; D016283:Proto-Oncogene Proteins p21(ras) / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D005456:Fluorescent Dyes; D006160:Guanosine Triphosphate; D016283:Proto-Oncogene Proteins p21(ras)