{
  "id": 78751,
  "title": "Dynamics of the α2-chimaerin-Rac1 interface in Duane retraction syndrome and computational design of candidate probes",
  "url": "https://urgent.news/2026/08/02/dynamics-of-the-2-chimaerin-rac1-interface-in-duane-retraction",
  "topic": "health",
  "section": "Health & Medicine",
  "published": "2026-08-02T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.07.29.741529v1?rss=1"
  },
  "original_language": "en",
  "account": "Duane retraction syndrome (DRS) stems from mutations in CHN1, a gene encoding 2-chimaerin. These mutations result in excessive suppression of Rac1, a protein crucial for axon guidance. The specifics of the CHN1-Rac1 interaction have been poorly understood until now. Researchers utilized all-atom molecular dynamics to simulate the CHN1-Rac1 complex, identifying key features of their interface. A hydrophobic ridge formed by Ile420 and Arg445 remained consistent across simulations. However, the 304-310 patch, hosting the catalytic arginine finger, displayed higher variability. A systematic screening of CHN1's BioGRID partners using AlphaFold3 and ipSAE revealed Rac1, NCK1, and NCK2 as potential binding partners. Among them, Rac1 and NCK1 exhibited persistent binding in all simulation replicates, while NCK2 held stable bonds in two out of three instances. The MM-GBSA interface free energy change (Delta)G for Rac1 was found to be -20 +/- 10 kcal/mol. The study further investigated how small molecules and peptides could interact with this surface. A strategy was employed to identify candidate chemical probes, starting with natural products from COCONUT, refining promising hits via CReM fragment growth, and generating peptides with BoltzGen. These ligands and peptides were then evaluated using molecular dynamics and MM-PBSA endpoint free-energy calculations. Over a cumulative simulation time of 6 microseconds, the contact network defining the CHN1-Rac1 interface successfully aligned with ligand and peptide engagement. This research elucidates the critical residues within the CHN1-Rac1 interface and pinpoints promising chemical probes for future experimental validation.",
  "summary": "Duane retraction syndrome (DRS) is an eye movement disorder caused by gain-of-function mutations in CHN1, which encodes 2-chimaerin. Mutations in CHN1 cause excessive Rac1 suppression during axon guidance, but the dynamics of the 2-chimaerin-Rac1 interaction remain largely uncharacterized. We simulated the CHN1-Rac1 complex with all-atom molecular dynamics to characterize this interface. An…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}