Siderocalin Q83 exhibits differential slow dynamics upon ligand binding

Author(s)
Nicolas Coudevylle, Leonhard Geist, Matthias Hoetzinger, Martin Tollinger, Robert Konrat
Abstract

Siderocalin Q83 is a small soluble protein that has the ability to bind two different ligands (enterobactin and arachidonic acid) simultaneously in two distinct binding sites. Here we report that Q83 exhibits an intriguing dynamic behavior. In its free form, the protein undergoes significant micro-to-millisecond dynamics. When binding arachidonic acid, the motions of the arachidonic acid binding site are quenched while the dynamics at the enterobactin binding site increases. Reciprocally, enterobactin binding to Q83 quenches the motions at the enterobactin binding site and increases the slow dynamics at the arachidonic acid binding site. Additionally, in the enterobactin-bound state, the excited state of the arachidonic acid binding site resembles the arachidonic acid-bound state. These observations strongly suggest an allosteric regulation where binding of one ligand enhances the affinity of Q83 for the other one. Additionally, our data strengthen the emerging view of proteins as dynamic ensembles interconverting between different sub-states with distinct functionalities.

Organisation(s)
Department of Structural and Computational Biology
External organisation(s)
Max F. Perutz Laboratories GmbH (MFPL), Leopold-Franzens-Universität Innsbruck
Journal
Journal of Biomolecular NMR
Volume
51
Pages
83-88
No. of pages
6
ISSN
0925-2738
DOI
https://doi.org/10.1007/s10858-011-9543-z
Publication date
2011
Peer reviewed
Yes
Austrian Fields of Science 2012
106041 Structural biology
Portal url
https://ucris.univie.ac.at/portal/en/publications/siderocalin-q83-exhibits-differential-slow-dynamics-upon-ligand-binding(f5e20673-e2ad-4b92-a2b6-1871ddbd93f7).html