{
  "id": 17537764,
  "title": "Structure of a secreted lancelet carotenoid cleavage dioxygenase (CCD), from an ancestral CCD clade",
  "url": "https://urgent.news/2026/10/31/structure-of-a-secreted-lancelet-carotenoid-cleavage-dioxygenase-ccd",
  "topic": "science",
  "section": "Science",
  "published": "2026-10-31T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.10.29.762971v1?rss=1"
  },
  "original_language": "en",
  "account": "Carotenoid cleavage dioxygenases (CCDs) are a superfamily of enzymes found in all living kingdoms. Scientists have recently discovered a new subfamily of CCDs, called beta-carotene oxygenase-like (BCOL) proteins, which are unique to chordates. These BCOL proteins are particularly prevalent in marine invertebrates like mollusks and lancelets.\n\nResearchers have now determined the 3D structure of a BCOL protein from the lancelet Branchiostoma floridae, known as BCOLg. This enzyme is capable of asymmetrically cleaving beta-carotene into all-trans retinal. The team found six out of seven annotated BCOL transcripts in Branchiostoma gut tissue through RNA sequencing.\n\nBCOLg is synthesized with four N-linked glycosylation sites, making it heavily glycosylated. Its structure belongs to the seven-bladed propeller fold category, which is typical of this enzyme family. Moreover, the protein exhibits a disulfide bond that contributes to its structural stability. Like other CCDs, BCOLg contains Asp substitutions at two of three Glu positions, which strengthens the three His residues responsible for Fe2+ coordination.\n\nInterestingly, BCOLg does not possess the characteristic -PDPCK- motif that is present in the majority of metazoan CCDs.",
  "summary": "Carotenoid cleavage dioxygenases (CCDs) are a superfamily of non-heme iron-containing enzymes ubiquitous across all kingdoms of life. Previously, we identified a new subfamily of CCDs termed beta-carotene oxygenase-like (BCOL) proteins, a chordate expansion of an ancestral sister clade of metazoan CCDs, which are widely distributed in marine invertebrates, including mollusks and lancelets. Here…",
  "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."
}