Tropomyosin Paracrystals Formed by Divalent Cations

Abstract
Rabbit tropomyosin exhibits a polymorphism dependent on divalent cations and pH. Above a critical divalent cation concentration fibers with a period of about 400 angstroms are formed. Below this concentration, and near the isoelectric point, lattices are formed. Implications for the morphology and function of striated and smooth muscle are discussed.
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