Anderson Jordan M, Kier Brandon L, Jurban Brice, Byrne Aimee, Shu Irene, Eidenschink Lisa A, Shcherbakov Alexander A, Hudson Mike, Fesinmeyer R M, Andersen Niels H
Department of Chemistry, University of Washington, Seattle, WA, 98195.
Biopolymers. 2016 Jun;105(6):337-356. doi: 10.1002/bip.22821.
We have extended our studies of Trp/Trp to other Aryl/Aryl through-space interactions that stabilize hairpins and other small polypeptide folds. Herein we detail the NMR and CD spectroscopic features of these types of interactions. NMR data remains the best diagnostic for characterizing the common T-shape orientation. Designated as an edge-to-face (EtF or FtE) interaction, large ring current shifts are produced at the edge aryl ring hydrogens and, in most cases, large exciton couplets appear in the far UV circular dichroic (CD) spectrum. The preference for the face aryl in FtE clusters is W ≫ Y ≥ F (there are some exceptions in the Y/F order); this sequence corresponds to the order of fold stability enhancement and always predicts the amplitude of the lower energy feature of the exciton couplet in the CD spectrum. The CD spectra for FtE W/W, W/Y, Y/W, and Y/Y pairs all include an intense feature at 225-232 nm. An additional couplet feature seen for W/Y, W/F, Y/Y, and F/Y clusters, is a negative feature at 197-200 nm. Tyr/Tyr (as well as F/Y and F/F) interactions produce much smaller exciton couplet amplitudes. The Trp-cage fold was employed to search for the CD effects of other Trp/Trp and Trp/Tyr cluster geometries: several were identified. In this account, we provide additional examples of the application of cross-strand aryl/aryl clusters for the design of stable β-sheet models and a scale of fold stability increments associated with all possible FtE Ar/Ar clusters in several structural contexts. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 337-356, 2016.
我们已将对色氨酸/色氨酸（Trp/Trp）的研究扩展至其他芳基/芳基（Aryl/Aryl）的通过空间相互作用，这些相互作用可稳定发夹结构及其他小多肽折叠结构。在此，我们详细阐述了这类相互作用的核磁共振（NMR）和圆二色性（CD）光谱特征。NMR数据仍是表征常见T形取向的最佳诊断方法。这种相互作用被指定为边对面（EtF或FtE）相互作用，在边缘芳基环氢处会产生大的环电流位移，并且在大多数情况下，在远紫外圆二色光谱（CD）中会出现大的激子偶合峰。在FtE簇中，对面芳基的偏好顺序为W≫Y≥F（Y/F顺序存在一些例外情况）；该顺序与折叠稳定性增强的顺序相对应，并且总能预测CD光谱中激子偶合峰较低能量特征的幅度。FtE W/W、W/Y、Y/W和Y/Y对的CD光谱在225 - 232 nm处均有一个强特征峰。在W/Y、W/F、Y/Y和F/Y簇中还可见到一个额外的偶合峰特征，即在197 - 200 nm处有一个负特征峰。酪氨酸/酪氨酸（Tyr/Tyr，以及F/Y和F/F）相互作用产生的激子偶合峰幅度要小得多。采用色氨酸笼折叠结构来探寻其他色氨酸/色氨酸和色氨酸/酪氨酸簇几何结构的CD效应：已鉴定出几种。在本报告中，我们提供了跨链芳基/芳基簇在稳定β-折叠模型设计中的应用的更多实例，以及在几种结构背景下与所有可能的FtE Ar/Ar簇相关的折叠稳定性增量尺度。© 2016威利期刊公司。生物聚合物105: 337 - 356, 2016。
