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A secondary structure of proteins, characterized by a single, spiral chain of amino acids stabilized by hydrogen bonds.
[From alpha-form, the form taken by unstretched protein molecules.]
al′pha-hel′i·cal (-hĕl′ĭ-kəl, -hē′lĭ-) adj.
(Biochemistry) biochem a helical conformation of a polypeptide chain, found abundantly in the structure of proteins
the spatial configuration of many protein molecules in which the polypeptide backbone is stabilized by hydrogen bonds between amino acids in successive helical turns.