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chemical ligation : ウィキペディア英語版 | chemical ligation
Chemical ligation is a set of techniques used for creating long peptide or protein chains. It is the second step of a convergent approach. First, smaller peptides containing 30-50 amino acids are prepared by conventional chemical peptide synthesis. Then, they are completely deprotected. Chemical ligation is the technique of coupling these peptides by chemoselective reaction to give a unique reaction product, usually in aqueous solution. With several coupling steps, proteins of up to 200-300 amino acids can be produced. ==Methods of chemical ligation== There are various techniques described in literature. The most practical and robust method for the chemoselective reaction of unprotected peptides is native chemical ligation. Native chemical ligation has overcome the limitations of the classical synthetic organic chemistry approach to the total synthesis of proteins, and enables the routine total or semi- synthesis of protein molecules. The original chemical ligation methods involved the formation of a non-native bond at the ligation site. Subsequently, native chemical ligation was developed. In native chemical ligation, an unprotected peptide-thioester reacts with a Cys-peptide to give a ligation product with a native amide ('peptide') bond at the ligation site. In this method, the initial thioester-linked ligation product intermediate rearranges to form an amide bond. Native chemical ligation relies on the presence of a cysteine residue at the ligation site. Methods using removable auxiliary groups can in some instances extend the use of native chemical ligation to non-cysteine residues, as can the use of desulfurization subsequent to the ligation (e.g. converting a Cys to an Ala).
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「chemical ligation」の詳細全文を読む
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