Sequential 1H NMR assignment and secondary structure determination of salmon calcitonin in solution.
Sequential 1H NMR assignment and secondary structure determination of salmon calcitonin in solution.
复制标题
溶液中鲑鱼降钙素的连续 1H NMR 归属和二级结构测定。
作者：
A. Motta;M. Morelli;N. Goud;P. Temussi
用核磁共振（NMR）技术研究了鲑鱼降钙素（sCT）在90%DMSOd6 - 10%1H2O（v/v）混合溶剂中的NMR谱，频率为500 MHz，温度为278 K。所有的骨架和侧链共振的激素已被分配通过使用高分辨率相敏二维技术。分析所观察到的连续核Overhauser效应的类型和幅度，NH-α CH自旋-自旋耦合常数，以及在278 K下在80%DMSOd6 - 20%2H2O（v/v）中测量的1H/2 H交换动力学，从而能够预测二级结构。总的来说，延伸构象是该溶液的主要特征，但在包含残基12-18的中心区域中存在短的双链反平行β折叠的明确指示，其通过由残基14-16形成的三残基发夹环连接。还鉴定了由残基6-9和25-28形成的两个紧转弯，但没有发现存在规则螺旋片段的证据。β折叠有利于残基的两亲性分布，使主要亲水性的Ser 13、Glu 15和His 17侧链定向在折叠平面上方，而主要疏水性的Leu 12、Gln 14和Leu 16定向在其下方。这被解释为两亲性α螺旋的“种子”，假定该两亲性α螺旋负责sCT与脂质的相互作用，这种情况让人想起信号肽在与膜相互作用中的折叠机制。顺反Pro23异构的可能意义进行了讨论。
Salmon calcitonin (sCT) has been investigated by NMR at 500 MHz in a 90% DMSOd6-10% 1H2O (v/v) mixture at 278 K. All backbone and side-chain resonances of the hormone have been assigned by using high-resolution phase-sensitive two-dimensional techniques. Analysis of the type and magnitude of the observed sequential nuclear Overhauser effects, the NH-alpha CH spin-spin coupling constants, and the 1H/2H exchange kinetics measured in 80% DMSOd6-20% 2H2O (v/v) at 278 K enabled prediction of the secondary structure. Overall, an extended conformation is the dominant feature of the solution, but there are clear indications for a short double-stranded antiparallel beta sheet in the central region comprising residues 12-18, connected by a three-residue hairpin loop formed by residues 14-16. Two tight turns, made by residues 6-9 and 25-28, were also identified, but no evidence was found for the presence of a regular helical segment. The beta sheet favors an amphipathic distribution of the residues, orienting the predominantly hydrophilic Ser13, Glu15, and His17 side chains above the plane of the sheet, and the predominantly hydrophobic Leu12, Gln14, and Leu16 below it. This is interpreted as the "seed" of the amphipathic alpha helix postulated to be responsible for the interaction of sCT with lipids, a situation reminiscent of the folding mechanism of signal peptides in the interaction with membranes. The possible significance of the cis-trans Pro23 isomerism is discussed.
影响因子：
56.9
作者：
BRIGGS, MS;CORNELL, DG;GIERASCH, LM
通讯作者：
GIERASCH, LM