Communication routes in ARID domains between distal residues in helix 5 and the DNA-binding loops

PLoS Comput Biol. 2014 Sep 4;10(9):e1003744. doi: 10.1371/journal.pcbi.1003744. eCollection 2014 Sep.

Abstract

ARID is a DNA-binding domain involved in several transcriptional regulatory processes, including cell-cycle regulation and embryonic development. ARID domains are also targets of the Human Cancer Protein Interaction Network. Little is known about the molecular mechanisms related to conformational changes in the family of ARID domains. Thus, we have examined their structural dynamics to enrich the knowledge on this important family of regulatory proteins. In particular, we used an approach that integrates atomistic simulations and methods inspired by graph theory. To relate these properties to protein function we studied both the free and DNA-bound forms. The interaction with DNA not only stabilizes the conformations of the DNA-binding loops, but also strengthens pre-existing paths in the native ARID ensemble for long-range communication to those loops. Residues in helix 5 are identified as critical mediators for intramolecular communication to the DNA-binding regions. In particular, we identified a distal tyrosine that plays a key role in long-range communication to the DNA-binding loops and that is experimentally known to impair DNA-binding. Mutations at this tyrosine and in other residues of helix 5 are also demonstrated, by our approach, to affect the paths of communication to the DNA-binding loops and alter their native dynamics. Overall, our results are in agreement with a scenario in which ARID domains exist as an ensemble of substates, which are shifted by external perturbation, such as the interaction with DNA. Conformational changes at the DNA-binding loops are transmitted long-range by intramolecular paths, which have their heart in helix 5.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • DNA / chemistry*
  • DNA / metabolism*
  • DNA-Binding Proteins / chemistry*
  • DNA-Binding Proteins / metabolism*
  • Humans
  • Molecular Dynamics Simulation
  • Protein Binding
  • Protein Structure, Tertiary
  • Transcription Factors / chemistry*
  • Transcription Factors / metabolism*

Substances

  • ARID3A protein, human
  • DNA-Binding Proteins
  • Transcription Factors
  • DNA

Grants and funding

This work was supported by the CASPUR Standard HPC Grants 2012 to EP and GI and by ISCRA-Cineca Grant 2012 (HP10C12N21) and 2013 (HP10CS5VQ7) to EP. Part of the simulations were carried out thanks to the DECI-11 Grant DyNet to EP. EP and KLL were supported by a Hallas-Møller stipend from the Novo Nordisk Foundation (to KLL). GI was supported by a Marie Curie IEF Fellowship. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.