{
  "id": 4341919,
  "title": "A structure-guided classification framework reveals the diversity and catalytic architecture of BECR ribonuclease",
  "url": "https://urgent.news/2026/08/29/a-structure-guided-classification-framework-reveals-the-diversity-and",
  "topic": "science",
  "section": "Science",
  "published": "2026-08-29T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.08.28.747851v1?rss=1"
  },
  "original_language": "en",
  "account": "Microbial organisms, present in every domain of life, utilize molecular warfare to outcompete others or react to biological threats. Ribonuclease toxins, a prevalent and varied subset, play a significant role in this context. A significant portion of these toxins belong to the BECR fold, a compact {beta} architecture enabling RNase function despite considerable variation. While several representative members of this class are well understood, many BECR-fold proteins remain challenging to identify due to low sequence similarity, varying catalytic residues, and structural features that complicate evolutionary connections. Recent advancements in high-confidence protein structure predictions offer an opportunity to reevaluate this extensive and varied protein family. This study utilizes iterative profile-HMM searches, profile-similarity networks, structural analyses, active-site mapping, and genomic context to investigate BECR proteins across the entire evolutionary tree. The investigation reveals a broader BECR-fold landscape encompassing both classic BECR and BECR-like families, refines the arrangement of conventional BECR proteins, and uncovers previously unknown families. Furthermore, the study confirms BECR-Tox2 as a toxin counteracted by a matching immunity protein and demonstrates that its homologs are found in both Menshen-like anti-phage systems and polymorphic toxin loci. In summary, these discoveries broaden and elucidate the BECR-fold landscape, offering a framework for recognizing and understanding highly divergent proteins of this fold.",
  "summary": "Microorganisms across all domains of life engage in molecular conflict, deploying toxins to inhibit competitors or respond to biological threats. Among these, ribonuclease toxins are particularly widespread and diverse. A substantial fraction is associated with the BECR fold, a compact /{beta} architecture that supports RNase activity despite extensive divergence. Although several canonical…",
  "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."
}