Transient electrostatic interactions dominate the conformational equilibrium sampled by multi-domain splicing factor U2AF65: A combined NMR and SAXS study.
 

Transient electrostatic interactions dominate the conformational equilibrium sampled by multi-domain splicing factor U2AF65: A combined NMR and SAXS study.

Related Articles Transient electrostatic interactions dominate the conformational equilibrium sampled by multi-domain splicing factor U2AF65: A combined NMR and SAXS study.

J Am Chem Soc. 2014 Apr 16;

Authors: Huang JR, Warner LR, Sanchez C, Gabel F, Madl T, Mackereth CD, Sattler M, Blackledge M

Abstract
Multi-domain proteins containing intrinsically disordered linkers exhibit large-scale dynamic modes that play key roles in a multitude of molecular recognition and signaling processes. Here we determine the conformational space sampled by the multi-domain splicing factor U2AF65 using complementary nuclear magnetic resonance spectroscopy and small angle scattering data. Available degrees of conformational freedom are initially stochastically sampled and experimental data then used to delineate the potential energy landscape in terms of statistical probability. The spatial distribution of U2AF65 conformations is found to be highly anisotropic, comprising significantly populated inter-domain contacts that appear to be electrostatic in origin. This hypothesis is supported by the reduction of signature PREs reporting on this interface with increasing salt concentration. The described spatial distribution reveals the complete spectrum of the unbound forms of U2AF65 that co-exist with the small percentage of a pre-formed RNA-bound domain arrangement required for polypyrimidine-tract recognition by conformational selection. The presence of a range of dynamically interconverting conformers may imply beneficial conformational entropy for unbound U2AF65. More generally, the proposed approach to describing conformational equilibria of multi-domain proteins can be further combined with other experimental data that are sensitive to domain dynamics.


PMID: 24734879 [PubMed - as supplied by publisher]



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