Conformational disorder of membrane peptides investigated from solid-state NMR line widths and line shapes.
Conformational disorder of membrane peptides investigated from solid-state NMR line widths and line shapes.
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DOI：
10.1021/jp205002n
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发表时间：
2011-09-15
影响因子：
3.3
通讯作者：
Hong, Mei
中科院分区：
文献类型：
--
作者：
Su, Yongchao;Hong, Mei
将固态核磁共振波谱应用于膜肽和膜蛋白时面临的一个挑战是，与溶液核磁共振波谱相比，其谱线宽度相对较宽。为了了解对膜蛋白核磁共振波谱线宽有贡献的因素，我们在固定条件下测量了几种研究较为透彻的膜肽的非均匀和均匀线宽。均匀标记了\(^{13}C\)的残基的\(^{13}C\ T_2\)弛豫时间表明，在相同的\(^{1}H\)去耦和魔角旋转条件下，这些肽的均匀线宽与晶体模型化合物的均匀线宽相当，这意味着均匀线宽是由与构象无关的因素决定的，包括剩余偶极耦合、\(J\)耦合和本征\(T_2\)弛豫。然而，膜肽表现出比晶体化合物更大的表观线宽，这表明存在构象无序。一种阳离子细胞穿透肽——人类免疫缺陷病毒TAT，表现出最大的表观线宽，大约是均匀线宽的5倍，而流感M2肽的跨膜螺旋以及β -发夹抗菌肽PG - 1表现出比晶体化合物适度更大的表观线宽。这些结果与TAT肽的无规卷曲性质相符，这与分子内氢键结合的M2和PG - 1形成对比。二维双量子相关谱的交叉峰线形表明，构象无序可以发生在残基水平，并且可能源于三个方面：脂质 - 肽相互作用、氨基酸序列中编码的本征构象无序以及侧链旋转异构体平均化。对于阳离子膜肽来说，一种特别重要的脂质 - 肽相互作用是胍盐 - 磷酸根离子对相互作用。因此，核磁共振线宽和线形对于理解膜肽和膜蛋白的构象无序是有用的。
A challenge in the application of solid-state NMR spectroscopy to membrane peptides and proteins is the relatively broad linewidths compared to solution NMR spectra. To understand the linewidth contributions to membrane protein NMR spectra, we have measured the inhomogeneous and homogeneous linewidths of several well-studied membrane peptides under immobilized conditions. 13C T2 relaxation times of uniformly 13C-labeled residues show that the homogeneous linewidths of the peptides are comparable to those of crystalline model compounds under identical 1H decoupling and magic-angle-spinning conditions, indicating that the homogeneous linewidths are determined by conformation-independent factors, including residual dipolar coupling, J coupling and intrinsic T2 relaxation. However, the membrane peptides exhibit larger apparent linewidths than the crystalline compounds, indicating conformational disorder. A cationic cell-penetrating peptide, the human immunodeficiency virus TAT, exhibits the largest apparent linewidths, which are about 5-fold larger than the homogeneous linewidths, while the transmembrane helix of the influenza M2 peptide and the β-hairpin antimicrobial peptide PG-1 show moderately larger apparent linewidths than the crystalline compounds. These results are consistent with the random coil nature of the TAT peptide, which contrasts with the intramolecularly hydrogen-bonded M2 and PG-1. Cross peak lineshapes of 2D double-quantum correlation spectra show that the conformational disorder can occur at the residue level and can result from three origins: lipid-peptide interaction, intrinsic conformational disorder encoded in the amino acid sequence, and sidechain rotameric averaging. A particularly important lipid-peptide interaction for cationic membrane peptides is guanidinium-phosphate ion pair interaction. Thus, NMR linewidths and lineshapes are useful for understanding the conformational disorder of membrane peptides and proteins.
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影响因子：
2.7
作者：
Cady SD;Hong M
通讯作者：
Hong M
影响因子：
4.4
作者：
BENNETT, AE;RIENSTRA, CM;GRIFFIN, RG
通讯作者：
GRIFFIN, RG
影响因子：
2.7
作者：
Akbey, Uemit;Lange, Sascha;Oschkinat, Hartmut
通讯作者：
Oschkinat, Hartmut
DOI：
10.1073/pnas.0900908106
发表时间：
2009-06-09
影响因子：
11.1
作者：
Bajaj, Vikram S.;Mak-Jurkauskas, Melody L.;Griffin, Robert G.
通讯作者：
Griffin, Robert G.
DOI：
10.1006/jmra.1993.1242
发表时间：
1993-10-15
期刊：
JOURNAL OF MAGNETIC RESONANCE SERIES A
影响因子：
--
作者：
COWANS, BA;GRUTZNER, JB
通讯作者：
GRUTZNER, JB