Lamassu Hydrolase-Protease system

traitmech:000567 · CLASS · PROPOSED

A Lamassu system in which an organism possesses a defense locus encoding a protease-domain LmuA effector together with a hydrolase-like protein, an SMC-like LmuB sensor, and LmuC.

Trait evidence (7)

DOI:10.1073/pnas.2519643122
Protease (accompanied by a hydrolase-like protein)

Results, effector-diversity paragraph: the protease branch is paired with a hydrolase-like protein in both long and short Lamassu. Figure 1A shows the paired architecture with LmuB and LmuC. These annotations do not establish exact effector substrates.
DOI:10.1073/pnas.2519643122
one system from Bacillus cereus B4077, encoding Hydrolase-Protease effectors

Results, LmuB phylogeny paragraph: identifies B4077 as the source of a previously validated long-Lamassu system, citing Millman et al. (2022). This supports a strain-qualified possession example, not species-wide prevalence or a native-host infection assay.
DOI:10.1016/j.chom.2022.09.017
Mutation in the effector domains of these systems also abolished defense, as well as the deletion of lmuC

Figure 2C and its Results paragraph report loss of defense after effector mutations or lmuC deletion in tested Lamassu systems, including the hydrolase/protease construct. The functional tests used heterologous hosts. This does not establish a substrate or the biochemical order of activation for the paired proteins.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/definitions/DefenseFinder/Lamassu-Fam/Lamassu_Hydrolase-Protease.xml
<model inter_gene_max_space="1" min_mandatory_genes_required="4" min_genes_required="4" vers="2.0">

The executable model requires four mandatory components, with at most one intervening gene between components.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/definitions/DefenseFinder/Lamassu-Fam/Lamassu_Hydrolase-Protease.xml
<gene name="Lamassu__LmuA_Protease" presence="mandatory"> <exchangeables> <gene name="Lamassu__LmuA_Protease_II"/> </exchangeables> </gene> <gene name="Lamassu__LmuA_Hydrolase" presence="mandatory"/>

The model requires both protease and hydrolase components; Protease_II can substitute for the primary protease profile. Separate mandatory blocks also require LmuB_Long (exchangeable with LmuB_Short) and LmuC_Clade_I (with listed alternatives).
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/definitions/DefenseFinder/Lamassu-Fam/Lamassu_Hydrolase-Protease.xml
<gene name="Lamassu__LmuC_Clade_I" presence="mandatory">

LmuC is mandatory in this executable model, with alternative LmuC profiles listed in its exchangeables block.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv
Lamassu-Fam Lamassu-Hydrolase_Protease 3 3

The summary TSV places the paired subtype within Lamassu-Fam but gives three mandatory matches and three genes. Its mandatory column lists the legacy Hydrolase, Protease and Cap4_nuclease_II SMC profiles, and its accessory column lists the Lipase LmuC profile. This summary disagrees with the executable XML at the same commit and is retained only as provenance for the older label.

Provenance

Identifier source: TraitMech local identifier
Definition source: DOI:10.1073/pnas.2519643122

Parent traits (1)

Lamassu type II system traitmech:000572

Synonyms (2)

Lamassu-Hydrolase_Protease RELATED_SYNONYM · https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv
Lamassu_Hydrolase-Protease RELATED_SYNONYM · https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/definitions/DefenseFinder/Lamassu-Fam/Lamassu_Hydrolase-Protease.xml

kg-microbe context

No kg-microbe node embedding matched this record in the 2026-04-25 deepwalk.

Canonical examples (1)

Organisms cited as exemplars of this trait. Taxon ids are NCBITaxon and link out to the NCBI record.

Bacillus cereus NCBITaxon:1396 DOI:10.1073/pnas.2519643122 Strain B4077 is the source of the experimentally validated long-Lamassu Hydrolase-Protease system identified by Haudiquet et al. with reference to Millman et al. (2022). The species identifier anchors this strain-qualified example; it does not imply that all B. cereus strains possess it.

Discussions and Knowledge Gaps (1)

Open questions attached to this trait. Seeded by just knowledge-gap-scan and curated; see the corpus-wide index.

Reconcile model-summary drift and resolve paired effector chemistry.

KNOWLEDGE GAP OPEN lamassu-hydrolase-protease-model-and-mechanism · raised by codex · 2026-10-03

Not yet attached to a section of this record — a curator sets attaches_to (e.g. causal_graphs#some_edge) so the gap shows beside the mechanism it concerns.

The pinned XML uses four mandatory components and newer Lamassu__ profile names, but its companion TSV uses three mandatory legacy profiles and accessory LmuC. The inventory's Hydrolase_protease LmuB and hydrolase_protease LmuC rows also differ from both representations. Model-summary reconciliation is required before using that TSV for genotype calls. The definition follows the biological paired architecture and executable model, not the table's thresholds. Exact substrates, activation order, native-host activity, and accession-level protein examples remain unresolved. No causal mechanism graph is asserted without those molecular anchors. The single-effector table-defined siblings are not asserted to be parents or equivalents of this paired system. The direct parent is now traitmech:000572 Lamassu type II system because the biological definition already includes LmuC. The paired effector architecture illustrates why type II is not restricted to exactly three genes. This refinement does not resolve the legacy detector-summary drift or assign the whole trait to one LmuB-length family.

Curation history

2026-10-03T09:29:00Z · MINTED_TRAITMECH_ID · codex
Added the literature-supported paired Lamassu architecture with DOI and pinned executable-model evidence, exact snippets, and a B4077 canonical example. Ignored-and-hidden searches found only pending parent mentions, not an exact existing record or METPO term. Reserved METPO:1052100 in proposals/metpo_traitmech_v444. Recorded summary-table drift rather than adopting its constraints.
2026-10-03T15:14:27Z · ADD_TYPE_II_PARENT · codex
Linked traitmech:000572 Lamassu type II system using the LmuC-containing classification in DOI:10.1093/nar/gkab883. Preserved biological definitions, evidence, examples and length-family distinctions. Historical proposal parent axioms remain true; v449 documents the additional subclass relations for upstream minting. This is not new experimental validation.