The fundamental units of collagen fibrils, consisting of three helically arranged polypeptide chains.
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tro·po·col·la·gen .träp-ə-'käl-ə-jən, .trōp- n a subunit of collagen fibrils consisting of three polypeptide strands arranged in a helix
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n.
the molecular unit of collagen. It consists of a helix of three collagen molecules: this arrangement confers on the fibres structural stability and resistance to stretching.
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tro·po·col·la·gen (tro″po-kolґə-jən) [tropo- + collagen] the basic structural unit of collagen; a helical structure consisting of three polypeptide chains, each chain composed of about a thousand amino acids, coiled around each other to form a spiral and stabilized by inter- and intrachain covalent bonds. It is rich in glycine, which occurs nearly one residue out of three, as well as in proline, hydroxyproline, and hydroxylysine; the last two rarely occur in other proteins.Medical dictionary. 2011.