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In statistical mechanics, the Zimm–Bragg model is a helix-coil transition model that describes helix-coil transitions of macromolecules, usually polymer chains. Most models provide a reasonable approximation of the fractional helicity of a given polypeptide; the Zimm–Bragg model differs by incorporating the ease of propagation with respect to nucleation. ==Helix-coil transition models== Helix-coil transition models assume that polypeptides are linear chains composed of interconnected segments. Further, models group these sections into two broad categories: ''coils'', random conglomerations of disparate unbound pieces, are represented by the letter 'C', and ''helices'', ordered states where the chain has assumed a structure stabilized by hydrogen bonding, are represented by the letter 'H'. Thus, it is possible to loosely represent a macromolecule as a string such as CCCCHCCHCHHHHHCHCCC and so forth. The number of coils and helices factors into the calculation of fractional helicity, , defined as : where : is the average helicity and : is the number of helix or coil units. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Zimm–Bragg model」の詳細全文を読む スポンサード リンク
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