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Updated: May 15, 2026

Comparing the Affinity of GTPase-binding Proteins using Competition Assays
Published on: October 8, 2015
Specific Conformational States of Ras GTPase upon Effector Binding
Julie Baussand1, Jens Kleinjung
1Division of Mathematical Biology, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, United Kingdom.
Ras GTPase binding to effectors involves subtle, local conformational changes. A computational method identified specific signaling routes and hot-spot residues, revealing mechanisms for effector specificity and Ras stabilization.
Area of Science:
- Molecular biology
- Structural biology
- Biophysics
Background:
- Ras GTPase plays a crucial role in cellular signaling pathways.
- Specific binding to downstream effectors is essential for Ras function.
- Understanding Ras-effector interactions is key to deciphering cellular regulation.
Purpose of the Study:
- To investigate the structural and dynamical changes in Ras GTPase upon effector binding.
- To identify the determinants of highly specific Ras-effector interactions.
- To elucidate the conformational mechanisms underlying Ras signaling specificity.
Main Methods:
- Molecular dynamics simulations of Ras in uncomplexed and complexed states.
- Cross-comparison of simulation trajectories.
- Application of a structural alphabet for quantifying local conformational changes.
Main Results:
- Identified effector-specific and effector-unspecific conformational changes in Ras.
- Discovered a set of nine structurally connected residues forming a potential effector-unspecific signaling route.
- Detected propagation of binding signals from the effector interface to distant hot-spot residues like Y5 and D57.
Conclusions:
- Ras-effector binding induces subtle local conformational changes influencing signaling.
- A conserved signaling route and hot-spot residues contribute to effector specificity.
- These findings provide insights into the conformational mechanisms stabilizing Ras activity and determining effector specificity.
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