Microsecond Timescale Dynamics of GDP-Bound Ras Underlies the Formation of Novel Inhibitor-Binding Pockets

The recent discovery of inhibitory compounds binding to distinct pockets on GDP‐bound Ras has renewed the view on the druggability of this crucial cancer driver. However, the origin of these pockets, which are not readily formed in the crystal structure in the absence of the compounds, is yet unclea...

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Bibliographic Details
Published in:	Angewandte Chemie 2016-12, Vol.128 (50), p.15858-15861
Main Authors:	Mao, Yunyun, Yao, Haijie, Wang, Hui, Cheng, Peng, Long, Dong
Format:	Article
Language:	eng ; ger
Subjects:	Binding Chemistry Correlation Crystal structure Dynamics Flexibility Inhibitorbindende Taschen Molekulare Erkennung NMR-Spektroskopie Origins Pocket Proteindynamik Ras Time
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Summary:	The recent discovery of inhibitory compounds binding to distinct pockets on GDP‐bound Ras has renewed the view on the druggability of this crucial cancer driver. However, the origin of these pockets, which are not readily formed in the crystal structure in the absence of the compounds, is yet unclear. Herein, we explored the intrinsic flexibility of Ras⋅GDP on microsecond to millisecond timescales using relaxation‐based NMR experiments, and identified substantial slow dynamics with τex of 34 μs at 5 °C, which maps to the regions showing a high level of correlation with those displaying conformational differences between the inhibitor‐bound and free states. These findings, which have been demonstrated in both wild‐type Ras and the oncogenic mutant (G12V), support the mechanism of extended conformational selection for Ras–inhibitor interactions where the small molecules redistribute the protein conformational ensemble favoring the final bound states. Relaxationsbasierte NMR‐Spektroskopie wurde genutzt, um die intrinsische Dynamik von GDP‐gebundenem Ras zu analysieren. Die Messungen ergeben eine langsame Austauschkorrelationszeit von 34 μs bei 5 °C und bestätigen einen hohen Grad an Korrelation mit den bei der Bindung niedermolekularer Inhibitoren umlagernden Regionen. Die Ergebnisse stützen den Mechanismus der Populationsumverteilung für die Bildung der neuartigen Bindungstaschen.
ISSN:	0044-8249 1521-3757