The structures of Exendin-4 (EX-4) and its analog in SDS micelles were studied by NMR spectroscopy. The results showed that EX-4 and its analog adopt α-helix structures with the N-termini disordered and the C-terminal parts folded as Trp-cage in the medium, but the EX-4 analog contains more helical turns in the N-terminal region than EX-4. The extension of helix to the N-terminus may favor affinity for extracellular domain of GLP-1 receptor and accurate positioning of the crucial N-terminal residues in the transmembrane domains responsible for receptor activation.%用核磁共振方法研究了十二烷基硫酸钠(SDS)胶束溶液中Exendin-4(EX-4)及其活性类似物的三维空间结构.结果表明,在SDS胶束溶液中EX-4及其活性类似物的结构都由具有α螺旋卷曲构象的中间区域、灵活的N端区域及形成Trp-cage结构的C端区域构成,但与原始肽结构不同的是类似物的螺旋区域向N端扩展了3个残基,螺旋结构向N端的延长可能改善了底物与受体的亲和力,提高了生物活性.
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