Nair M M, Jackson G E, Gäde G
Department of Chemistry, University of Cape Town, South Africa.
J Comput Aided Mol Des. 2001 Mar;15(3):259-70. doi: 10.1023/a:1008123604588.
Mem-CC (pGlu-Leu-Asn-Tyr-Ser-Pro-Asp-Trp-NH2), Tem-HrTH (pGlu-Leu-Asn-Phe-Ser-Pro-Asn-Trp-NH2) and Del-CC (pGlu-Leu-Asn-Phe-Ser-Pro-Asn-Trp-Gly-Asn-NH2) are adipokinetic hormones, isolated from the corpora cardiaca of different insect species. These hormones regulate energy metabolism during flight and so are intimately involved in an insect's mobility. Secondary structural elements of these peptides and the N7 analogue, [N7]-Mem-CC (pGlu-Leu-Asn-Tyr-Ser-Pro-Asn-Trp-NH2), have been determined in dimethylsulfoxide solution using NMR restrained molecular mechanic simulations. The neuropeptides were all found to have an extended structure for the first 4 residues and a beta-turn between residues 4-8. For Tem-HrTH and Del-CC, asparagine (N7) which is postulated to be involved in receptor binding and/or activation, projects outward form the beta-turn. Mem-CC does not have an asparagine at position 7 while, for [N7]-Mem-CC, the N7 sidechain folds inside the beta-turn preventing its interaction with the receptor.
Mem - CC（焦谷氨酸 - 亮氨酸 - 天冬酰胺 - 酪氨酸 - 丝氨酸 - 脯氨酸 - 天冬氨酸 - 色氨酸 - 氨基）、Tem - HrTH（焦谷氨酸 - 亮氨酸 - 天冬酰胺 - 苯丙氨酸 - 丝氨酸 - 脯氨酸 - 天冬酰胺 - 色氨酸 - 氨基）和Del - CC（焦谷氨酸 - 亮氨酸 - 天冬酰胺 - 苯丙氨酸 - 丝氨酸 - 脯氨酸 - 天冬酰胺 - 色氨酸 - 甘氨酸 - 天冬酰胺 - 氨基）是从不同昆虫物种的心侧体中分离出的脂肪动激素。这些激素在飞行过程中调节能量代谢，因此与昆虫的活动密切相关。利用核磁共振受限分子力学模拟，已在二甲亚砜溶液中确定了这些肽及其N7类似物[N7] - Mem - CC（焦谷氨酸 - 亮氨酸 - 天冬酰胺 - 酪氨酸 - 丝氨酸 - 脯氨酸 - 天冬酰胺 - 色氨酸 - 氨基）的二级结构元件。所有神经肽在前4个残基处均具有伸展结构，在残基4 - 8之间有一个β - 转角。对于Tem - HrTH和Del - CC，据推测参与受体结合和/或激活的天冬酰胺（N7）从β - 转角向外突出。Mem - CC在第7位没有天冬酰胺，而对于[N7] - Mem - CC，N7侧链折叠在β - 转角内部，阻止其与受体相互作用。
