{
  "abstract": "Nearly all bacteria are surrounded by a mesh-like macromolecule called peptidoglycan that gives them their shape and helps them resist turgor pressure. To grow and maintain their peptidoglycan, bacteria produce a wide range of enzymes, including the relatively understudied ,[x1D05]-transpeptidase (LDT) family. LDTs can catalyse several different reactions and vary widely in copy number: some bacteria have none, whilst others have more than twenty. To better understand why some bacteria have so many LDTs, we examined 18 putative ones from Rhizobium johnstonii, a nitrogen-fixing, symbiotic bacterium. Heterologous expression revealed several highly active enzymes, one of which, LdtRj8, we further characterized in detail. In vitro assays showed that LdtRj8 was capable of ,[x1D05]-transpeptidation, carboxypeptidation, substitution, and endopeptidation, but that its preferred activity differed at different pHs. LdtRj8 particularly excelled at ,[x1D05]-substitution, utilizing all of the tested [x1D05]-amino acids, and, surprisingly, most of the -amino acids as well. LdtRj8's pH-modulated activity could help R. johnstonii respond to acidic conditions encountered throughout the rhizobium-legume symbiosis, and its -amino acid substitution activity, which we show to be a more general property of LDTs, may regulate ,[x1D05]-transpeptidation and explain the existence of isomeric muropeptides often reported in the literature.",
  "abstract_shown": true,
  "affiliations": [
    "The University of Sheffield"
  ],
  "article_type": "New results",
  "arxiv": null,
  "author_total": 4,
  "authors": [
    {
      "name": "B. J. Rady"
    },
    {
      "name": "R. Bahadur"
    },
    {
      "name": "C. A. Evans"
    },
    {
      "affs": [
        0
      ],
      "name": "S. Mesnage"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/6mrdhf3ddsg01.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.06.30.735398",
  "fulltext_url": "https://www.biorxiv.org/content/10.64898/2026.06.30.735398v2.full",
  "id": "6mrdhf3ddsg01",
  "issns": [],
  "landing_url": "https://www.biorxiv.org/content/10.64898/2026.06.30.735398v2",
  "language": null,
  "licence": "CC-BY-NC",
  "licence_label": "CC BY-NC",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "biorxiv",
      "biochemistry"
    ],
    [
      "openalex",
      "1311|Bacterial Genetics and Biotechnology"
    ]
  ],
  "openalex": "W7166888191",
  "pdf_url": "https://www.biorxiv.org/content/10.64898/2026.06.30.735398v2.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-06-30",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/6mrdhf3ddsg01.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:34Z",
      "native_id": "10.64898/2026.06.30.735398",
      "source": "biorxiv",
      "url": "https://www.biorxiv.org/content/10.64898/2026.06.30.735398v2"
    }
  ],
  "subjects": [
    {
      "field": "biology",
      "origin": "openalex:1311|Bacterial Genetics and Biotechnology",
      "subfield": "genetics-genomics"
    }
  ],
  "title": "Rhizobial enzyme reveals pH-driven catalytic switching and ʟ-amino acid incorporation by ʟ,-transpeptidases",
  "title_text": "Rhizobial enzyme reveals pH-driven catalytic switching and ʟ-amino acid incorporation by ʟ,-transpeptidases",
  "type": "preprint",
  "updated_at": "2026-10-30T12:18:34Z",
  "url": "https://research.draconitic.com/paper/6mrdhf3ddsg01",
  "venue": "bioRxiv",
  "versions": []
}