Polypharmacology within CXCR4: Multiple binding sites and allosteric behavior

Jesús M. Planesas, Violeta I. Pérez-Nueno, José I. Borrell, Jordi Teixidó

Research output: Book chapterConference contributionpeer-review

Abstract

CXCR4 is a promiscuous receptor, which binds multiple diverse ligands. As usual in promiscuous proteins, CXCR4 has a large binding site, with multiple subsites, and high flexibility. Hence, it is not surprising that it is involved in the phenomenon of allosteric modulation. However, incomplete knowledge of allosteric ligand-binding sites has hampered an in-depth molecular understanding of how these inhibitors work. For example, it is known that lipidated fragments of intracellular GPCR loops, so called pepducins, such as pepducin ATI-2341, modulate CXCR4 activity using an agonist allosteric mechanism. Nevertheless, there are also examples of small organic molecules, such as AMD11070 and GSK812397, which may act as antagonist allosteric modulators. Here, we give new insights into this issue by proposing the binding interactions between the CXCR4 receptor and the above-mentioned allosteric modulators. We propose that CXCR4 has minimum two topographically different allosteric binding sites. One allosteric site would be in the intracellular loop 1 (ICL1) where pepducin ATI-2341 would bind to CXCR4, and the second one, in the extracellular side of CXCR4 in a subsite into the main orthosteric binding pocket, delimited by extracellular loops n° 1, 2, and the N-terminal end, where antagonists AMD11070 and GSK812397 would bind. Prediction of allosteric interactions between CXCR4 and pepducin ATI-2341 were studied first by rotational blind docking to determine the main binding region and a subsequent refinement of the best pose was performed using flexible docking methods and molecular dynamics. For the antagonists AMD11070 and GSK812397, the entire CXCR4 protein surface was explored by blind docking to define the binding region. A second docking analysis by subsites of the identified binding region was performed to refine the allosteric interactions. Finally, we identified the binding residues that appear to be essential for CXCR4 (agonists and antagonists) allosteric modulators.

Original languageEnglish
Title of host publicationInternational Conference of Computational Methods in Sciences and Engineering 2014, ICCMSE 2014
EditorsTheodore E. Simos, Theodore E. Simos, Theodore E. Simos, Theodore E. Simos, Theodore E. Simos, Zacharoula Kalogiratou, Theodore Monovasilis
PublisherAmerican Institute of Physics Inc.
Pages1036-1038
Number of pages3
ISBN (Electronic)9780735412552
DOIs
Publication statusPublished - 6 Oct 2014
EventInternational Conference of Computational Methods in Sciences and Engineering 2014, ICCMSE 2014 - Athens, Greece
Duration: 4 Apr 20147 Apr 2014

Publication series

NameAIP Conference Proceedings
Volume1618
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Conference

ConferenceInternational Conference of Computational Methods in Sciences and Engineering 2014, ICCMSE 2014
Country/TerritoryGreece
CityAthens
Period4/04/147/04/14

Keywords

  • CXCR4
  • Polypharmacology
  • allostery
  • binding subsites

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