Cooperativity between the orthosteric.pdf (2.03 MB)
Download file

Cooperativity between the orthosteric and allosteric ligand binding sites of RORγt

Download (2.03 MB)
journal contribution
posted on 06.07.2021, 11:43 by RMJM de Vries, FA Meijer, RG Doveston, IA Leijten-Van de Gevel, L Brunsveld
Cooperative ligand binding is an important phenomenon in biological systems where ligand binding influences the binding of another ligand at an alternative site of the protein via an intramolecular network of interactions. The underlying mechanisms behind cooperative binding remain poorly understood, primarily due to the lack of structural data of these ternary complexes. Using time-resolved fluorescence resonance energy transfer (TR-FRET) studies, we show that cooperative ligand binding occurs for RORγt, a nuclear receptor associated with the pathogenesis of autoimmune diseases. To provide the crucial structural insights, we solved 12 crystal structures of RORγt simultaneously bound to various orthosteric and allosteric ligands. The presence of the orthosteric ligand induces a clamping motion of the allosteric pocket via helices 4 to 5. Additional molecular dynamics simulations revealed the unusual mechanism behind this clamping motion, with Ala355 shifting between helix 4 and 5. The orthosteric RORγt agonists regulate the conformation of Ala355, thereby stabilizing the conformation of the allosteric pocket and cooperatively enhancing the affinity of the allosteric inverse agonists.

Funding

This work was supported by the Netherlands Organization for Scientific Research through Gravity program 024.001.035 and Vici grant 016.150.366 and the European Union through a Marie Skłodowska-Curie Actions (MSCA) Individual Fellowship (R.G.D., H2020-MSCA-IEF-2016, grant no. 705188).

History

Citation

PNAS, 2021 118 (6) e2021287118

Author affiliation

School of Chemistry

Version

VoR (Version of Record)

Published in

Proceedings of the National Academy of Sciences (PNAS)

Volume

118

Issue

6

Publisher

National Academy of Sciences

issn

0027-8424

eissn

1091-6490

Acceptance date

31/12/2020

Copyright date

2021

Available date

06/07/2021

Spatial coverage

United States

Language

eng