Weber P L, Brown S C, Mueller L
Department of Physical and Structural Chemistry, Smith Kline and French Laboratories, King of Prussia, Pennsylvania 19406-0939.
Biochemistry. 1987 Nov 17;26(23):7282-90. doi: 10.1021/bi00397a013.
1H NMR assignments of human ubiquitin (76 amino acids, Mr 8565) have been made by a combination of DQF-COSY, DQF-RELAY, NOESY, DQ, and isotropic mixing experiments. Complete NH, C alpha H, and C beta H assignments were obtained; resonances not yet assigned are the side-chain amides of Q-40, Q-41, Q-49, N-60, and Q-62 and the peripheral protons (C gamma H and outward) of M-1 and K-27. A total of 558 out of 579 (96%) potentially observable protons were assigned. Particular attention was directed toward obtaining complete assignments of the aliphatic residues (seven Ile, nine Leu, four Val) since these residues form an extensive hydrophobic core and NOEs from these residues are invaluable for structure calculations. The secondary structure elements were also identified from the sequential NOE data and differ slightly in description from the published 2.8 A resolution crystal structure [Vijay-Kumar, S., Bugg, C. E., Wilkinson, K. D., & Cook, W. J. (1985) Proc. Natl. Acad. Sci. U.S.A. 82, 3582-3585]; the NMR data suggest that residues 48-50 form a short fifth strand in the beta-sheet and that residues 56-61 form a helical turn. The sequential assignment results presented here are in agreement with the main chain directed assignments presented in the preceding paper [Di Stephano, D., & Wand, A. J. (1987) Biochemistry (preceding paper in this issue)].
通过双量子滤波相关谱（DQF - COSY）、双量子滤波接力相关谱（DQF - RELAY）、核Overhauser效应谱（NOESY）、双量子（DQ）和各向同性混合实验相结合的方法，已完成了人泛素（76个氨基酸，分子量8565）的¹H核磁共振（NMR）归属。获得了完整的NH、CαH和CβH归属；尚未归属的共振峰是第40位谷氨酰胺（Q - 40）、第41位谷氨酰胺（Q - 41）、第49位谷氨酰胺（Q - 49）、第60位天冬酰胺（N - 60）和第62位谷氨酰胺（Q - 62）的侧链酰胺以及第1位甲硫氨酸（M - 1）和第27位赖氨酸（K - 27）的外周质子（CγH及向外的质子）。在579个潜在可观测质子中，共归属了558个（96%）。特别关注获得脂肪族残基（7个异亮氨酸、9个亮氨酸、4个缬氨酸）的完整归属，因为这些残基形成了一个广泛的疏水核心，并且来自这些残基的核Overhauser效应（NOE）对于结构计算非常重要。二级结构元件也从序列NOE数据中得以鉴定，其描述与已发表的2.8埃分辨率晶体结构[Vijay - Kumar, S., Bugg, C. E., Wilkinson, K. D., & Cook, W. J. (1985) Proc. Natl. Acad. Sci. U.S.A. 82, 3582 - 3585]略有不同；NMR数据表明，第48 - 50位残基在β - 折叠中形成一条短的第五条链，并且第56 - 61位残基形成一个螺旋转角。这里给出的序列归属结果与前文[Di Stephano, D., & Wand, A. J. (1987) Biochemistry（本期前文）]中基于主链的归属结果一致。
