Allosteric Conformational Locking of Sestrin2 by Leucine: An Integrated Computational Analysis of Branched-Chain Amino Acid Recognition and Specificity.
Level 5 - mechanism / opinion, no new human data
In silico computational biophysical study without biological or clinical subjects
PubMed 41471815 · doi:10.3390/molecules30244791
What was done
The authors used an integrated in silico computational pipeline—combining molecular docking, all-atom molecular dynamics simulations, and binding free energy calculations—to evaluate the structural, thermodynamic, and dynamic basis of Sestrin2 (SESN2) binding specificity for leucine compared to isoleucine and valine.
What was found
Thermodynamic analysis demonstrated a binding affinity hierarchy of Leucine > Isoleucine > Valine, mediated primarily by van der Waals interactions and shape complementarity of leucine's isobutyl side chain in the hydrophobic pocket. Leucine binding induced conformational locking, collapsing the unbound protein's structural ensemble from 35 distinct conformations into 9 stable states (a four-fold reduction) and lowering transition rates between states. Absolute free energy and affinity values were not provided in the abstract.
Why it matters
This study defines the structural and dynamic mechanism of Sestrin2's selectivity for leucine in mTORC1 regulation, providing a molecular basis for designing SESN2-targeted allosteric therapeutics.
Limits
The study relies entirely on in silico computational modeling without experimental in vitro or in vivo biological validation reported in the abstract. Quantitative binding free energy values and kinetic rates are not numerically reported in the abstract text.
Cited by
- supports Among the three branched-chain amino acids, leucine is the main driver of mTORC1 activation, while isoleucine and valine are virtually irrelevant.