In molecular biology, the calponin family repeat is a 26 amino acid protein domain.
Calponin 1 (CNN1) contains three copies of this domain.
This domain is also found in vertebrate smooth muscle protein (SM22 or transgelin), and a number of other proteins whose physiological role is not yet established, including Drosophila synchronous flight muscle protein SM20, Caenorhabditis elegans unc-87 protein,[1] rat neuronal protein NP25,[2] and an Onchocerca volvulus antigen.
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