hamus

cellstructuremech:hamus · Appendage · Appendage · Proposed

An archaeal cell-surface appendage composed of proteinaceous helical filaments with periodic prickles and a terminal grappling hook, used by Candidatus Altarchaeum hamiconexum cells to attach to biotic and abiotic surfaces. [DOI:10.1111/j.1365-2958.2005.04294.x]

Synonyms: hami; altiarchaeal grappling hook; nano-grappling hook

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
hamus 120 kDa subunits	Protein	part of	Reviewed label only (reviewed name; no accession asserted)			UNKNOWN	Major proteinaceous constituents of the extracellular helical filament and terminal hook. `DOI:10.1111/j.1365-2958.2005.04294.x` Moissl et al. 2005 biochemically and ultrastructurally characterized hami as mostly 120 kDa proteinaceous subunits assembled into helical appendages with grappling-hook termini. `DOI:10.3389/fmicb.2015.00543` Perras et al. 2015 compared the grappling-hook hami of Candidatus Altarchaeum hamiconexum with archaeal S-layer proteins in sequence and structure.

Taxonomic distribution

NCBITaxon:1803513 Candidatus Altarchaeum hamiconexum — COMMON: Hami were ultrastructurally characterized on cells of the uncultivated SM1/Altarchaeum archaeon from cold sulphidic springs. [DOI:10.1111/j.1365-2958.2005.04294.x]

Canonical examples

NCBITaxon:1803513 Candidatus Altarchaeum hamiconexum — Uncultivated archaeal species whose surface hami were described by electron microscopy and cryo-electron tomography. [DOI:10.1111/j.1365-2958.2005.04294.x]

Functions

biotic and abiotic surface adhesion — Hami project from the archaeal cell surface and mediate strong adhesion to chemically distinct biotic and abiotic surfaces.
- DOI:10.1111/j.1365-2958.2005.04294.x Moissl et al. 2005 connected each cell's halo of hami with adhesion to surfaces of different chemical composition.
- DOI:10.3389/fmicb.2014.00397 Perras et al. 2014 localized hami as major contact structures at the SM1/Altarchaeum cell surface in biofilm ultrastructure.

Mechanism graphs

Proteinaceous hami present grappling hooks for surface adhesion (FUNCTION)

The hami of Candidatus Altarchaeum hamiconexum contain 120 kDa subunits and present a helical filament with periodic prickles and a terminal grappling hook from the cell surface to mediate adhesion to biotic and abiotic surfaces.

Subject	Predicate	Object	Evidence
hamus 120 kDa subunits	are major constituents of	helical hamus filament	`DOI:10.1111/j.1365-2958.2005.04294.x` Moissl et al. 2005 characterized the dominant 120 kDa hamus subunits and the helical appendage ultrastructure.
helical hamus filament	bears	periodic hamus prickles	`DOI:10.1111/j.1365-2958.2005.04294.x` Moissl et al. 2005 resolved periodic prickles along the helical hamus structure.
helical hamus filament	terminates in	terminal grappling hook	`DOI:10.1111/j.1365-2958.2005.04294.x` Moissl et al. 2005 identified a tripartite barbed grappling hook at the distal end of the hamus.
terminal grappling hook	is part of	hamus	`DOI:10.1111/j.1365-2958.2005.04294.x` Moissl et al. 2005 combined whole-hamus electron microscopy with cryo-ET of the distal grappling-hook region.
hamus	mediates	biotic and abiotic surface adhesion	`DOI:10.1111/j.1365-2958.2005.04294.x` Moissl et al. 2005 connected hami with strong cell adhesion to chemically distinct surfaces. `DOI:10.3389/fmicb.2014.00397` Perras et al. 2014 analyzed how hami occupy cell-surface contact sites in archaeal biofilms.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral protein-family groundings and component boundaries for Candidatus Altarchaeum hamiconexum hamus subunits. The first hamus record keeps the 120 kDa structural proteins as a label-only cohort because this uncultivated archaeon's hami have not yet been mapped here to an exact InterPro, Pfam or NCBIfam accession.

Evidence

DOI:10.1111/j.1365-2958.2005.04294.x Moissl et al. 2005, The unique structure of archaeal hami, highly complex cell appendages with nano-grappling hooks, Molecular Microbiology.
DOI:10.3389/fmicb.2014.00397 Perras et al. 2014, Grappling archaea: ultrastructural analyses of an uncultivated, cold-loving archaeon, and its biofilm, Frontiers in Microbiology.
DOI:10.3389/fmicb.2015.00543 Perras et al. 2015, S-layers at second glance? Altiarchaeal grappling hooks (hami) resemble archaeal S-layer proteins in structure and sequence, Frontiers in Microbiology.

Curation history

2026-09-11T13:44:40Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-11T13:45:26Z codex · EXPANDED_RECORD — Added hamus synonymy, cell-projection parentage, a label-only 120 kDa protein subunit component, Candidatus Altarchaeum hamiconexum distribution and exemplar rows, surface-adhesion function evidence, DOI provenance, a nonmechanistic hami surface-attachment graph, and a protein-family grounding TODO.
2026-09-11T13:55:17Z codex · ADDRESS_REVIEW — Resolved #490 by removing biofilm context from the Moissl-backed taxonomic note, resolved #491 by narrowing the canonical example to Moissl-backed EM and cryo-ET characterization, and resolved #492 by changing the first graph edge from an assembly claim to a constituent claim.

Source: data/structures/appendage/hamus.yaml