HORMAdomainlike

HORMAdomainlike refers to protein regions or whole proteins that show structural or sequence similarity to the HORMA domain, a conserved module named for its presence in Hop1, Rev7, and MAD2. The HORMA domain is involved in protein–protein interactions and can undergo conformational changes between open and closed states, often in association with a closure motif. HORMAdomainlike annotations typically arise in bioinformatic analyses when an uncharacterized protein region yields a detectable resemblance to known HORMA domains through profile-based methods or comparative structural modeling.

Key features of HORMAdomainlike regions include a core fold resembling the HORMA domain and, in some cases, elements that hint at regulatory interactions with partner proteins. However, sequence similarity to canonical HORMA domains can be low, and structural modeling or experimental validation is often required to confirm a true HORMA-like fold. The biological significance of HORMAdomainlike regions is variable: some may represent bona fide HORMA-domain–like interaction modules that participate in meiosis or DNA damage response pathways, while others may be distant or divergent relatives without a defined function.

Identification approaches combine computational and experimental strategies. Computationally, researchers use hidden Markov models and other profile-based tools against HORMA-domain databases, supplemented by structural prediction techniques. Experimentally, validation may involve protein expression and purification, crystallography or cryo-EM to confirm folding, and interaction assays to establish partner binding. As a comparative concept, HORMAdomainlike serves as a useful label for exploring potential HORMA-like architecture in uncharacterized proteins. See also HORMA domain; Hop1; Rev7; MAD2.