{
  "abstract": "Alkylsuccinate synthase (AssA / MasD) catalyses fumarate-dependent anaerobic alkane activation. Characterised enzymes are confined to a few cultured sulfate reducers, nitrate-reducers and the archaeon Archaeoglobus fulgidus, and each acts over a narrow carbon-number range. Sequence similarity alone does not separate AssA from its glycyl-radical paralogs. Screening GTDB r232 recovered 1,272 AssA-like MAGs across 28 phyla. The catalytic glycyl-radical core is invariant across the recovered sequences, so it cannot identify AssA. Discrimination rests instead on two clade-variable features: completeness of the assABCDE operon and retention of the (1-methylalkyl)succinate synthase (MASS) pocket. On these criteria the 1,272 MAGs yield only 92 canonical AssA sequences (Clade A1), 89 of them with an assignable host MAG. The rest fall into a paralog-like Clade A2 (n = 29), a divergent AssA-like Clade B (n = 251) and a pyruvate-formate-lyase-paralog comparator (Clade C, n = 900). An assA marker screen retaining all homology hits therefore over-recovers non-degraders more than several fold. Canonical AssA nonetheless extends well beyond the cultured Desulfobacterota into additional bacterial phyla with no prior record, most of them on the evidence of a single MAG, and includes largely uncultivated hosts such as SAR324 and Spirochaetota. Clades A2 and B carry no accessory subunits and match neither the MASS pocket nor the benzylsuccinate-synthase pocket. Neither clade contains a characterised enzyme, so their substrates cannot be assigned. Carriers derive predominantly from anoxic, hydrocarbon-bearing habitats, and gene-tree/species-tree discordance is consistent with horizontal mobility of assA. Operon and pocket criteria therefore provide a benchmark against misannotation of glycyl-radical enzymes in environmental datasets. The substrate of Clades A2 and B is the priority for biochemical work.",
  "abstract_shown": true,
  "affiliations": [
    "Institutional Research Office, Manila Central University",
    "Department of Biology, College of Arts and Sciences, Manila Central University"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 3,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Boonfei Tan"
    },
    {
      "affs": [
        1
      ],
      "name": "Christian Zafra"
    },
    {
      "affs": [
        0
      ],
      "name": "Charmaine Ng"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/6ery8a1e2raam.bib",
  "cited_by": 0,
  "doi": "10.1038/s41598-026-71283-x",
  "fulltext_url": "https://doi.org/10.1038/s41598-026-71283-x",
  "id": "6ery8a1e2raam",
  "issns": [
    "2045-2322"
  ],
  "landing_url": "https://doi.org/10.1038/s41598-026-71283-x",
  "language": "en",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "lcc",
      "Q"
    ],
    [
      "lcc",
      "R"
    ],
    [
      "openalex",
      "2310|Microbial bioremediation and biosurfactants"
    ]
  ],
  "openalex": "W7213353785",
  "pdf_url": "https://www.nature.com/articles/s41598-026-71283-x_reference.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-01",
  "publisher": "Nature Portfolio",
  "ris": "https://research.draconitic.com/paper/6ery8a1e2raam.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T13:45:58Z",
      "native_id": "a7aea93b32a84697b062b4c088cf5142",
      "source": "doaj",
      "url": "https://doi.org/10.1038/s41598-026-71283-x"
    }
  ],
  "subjects": [
    {
      "field": "earth",
      "origin": "openalex:2310|Microbial bioremediation and biosurfactants",
      "subfield": "environmental-science"
    }
  ],
  "title": "Phylogenomic survey of GTDB r232 expands the taxonomic and ecological range of alkylsuccinate synthase and distinguishes divergent AssA-like paralogs",
  "title_text": "Phylogenomic survey of GTDB r232 expands the taxonomic and ecological range of alkylsuccinate synthase and distinguishes divergent AssA-like paralogs",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T13:45:58Z",
  "url": "https://research.draconitic.com/paper/6ery8a1e2raam",
  "venue": "Scientific Reports",
  "versions": []
}