Blackledge M J, Brüschweiler R, Griesinger C, Schmidt J M, Xu P, Ernst R R
Laboratorium für Physikalische Chemie, Eidgenössische Technische Hochschule, Zürich, Switzerland.
Biochemistry. 1993 Oct 19;32(41):10960-74. doi: 10.1021/bi00092a005.
A general procedure for the analysis of biomolecular structures by NMR in the presence of rapid conformational dynamics has been applied to the study of the cyclic decapeptide antamanide. Two-dimensional experiments, relaxation measurements in the rotating frame, and homo- and heteronuclear coupling constant determinations have been used to characterize the dynamic properties of the molecule, in combination with a novel search algorithm for investigating multiconformational equilibria. Direct evidence for the presence of a conformational exchange process with an activation energy of approximately 20 kJ mol-1 and an exchange lifetime of approximately 25 microseconds at 320 K has been obtained from rotating frame relaxation measurements. This evidence is combined with the information derived from the multiconformational search algorithm MEDUSA to propose sets of structures that coexist in a dynamic exchange equilibrium.
一种在快速构象动力学存在的情况下通过核磁共振分析生物分子结构的通用程序已应用于环十肽抗霉素A的研究。二维实验、旋转坐标系中的弛豫测量以及同核和异核耦合常数测定已被用于表征该分子的动力学性质，并结合一种用于研究多构象平衡的新型搜索算法。通过旋转坐标系弛豫测量获得了在320K时存在构象交换过程的直接证据，其活化能约为20kJ/mol，交换寿命约为25微秒。该证据与从多构象搜索算法MEDUSA得出的信息相结合，提出了在动态交换平衡中共存的结构集。
