Structural similarities of micelle-bound peptide YY (PYY) and neuropeptide Y (NPY) are related to their affinity profiles at the Y receptors
Structural similarities of micelle-bound peptide YY (PYY) and neuropeptide Y (NPY) are related to their affinity profiles at the Y receptors
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DOI：
10.1016/j.jmb.2004.04.032
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发表时间：
2004-06-18
影响因子：
5.6
通讯作者：
Zerbe, O
中科院分区：
文献类型：
--
作者：
Lerch, M;Mayrhofer, M;Zerbe, O
在这里，我们研究了猪肽YY（pPYY）的结构时，在pH 4.2的溶液中解开时，在pH 5.5的十二烷基磷酸胆碱（DPC）胶束结合。溶液中的pPYY显示PP-折叠，其中N-末端区段反向折叠到C-末端α-螺旋上，其从残基17延伸到31。与Keire等人在2000年发表的溶液结构相反，C-末端螺旋在残基23-25周围不显示扭结。对于残基14-31，构象异构体的NMR系综的骨架原子与平均结构的均方根偏差（RMSD）为0.99（+/-0.35）埃。N-15{H-1}-NOE的值为0.60 +/- 0.1，残基5-31的广义有序参数S-2为0.74 +/- 0.1，这表明肽在该片段中折叠，支持了反向折叠。我们还使用DPC胶束作为膜模型，并确定了pPYY与其结合时的结构，其中，在包含残基17-31的片段中存在α-螺旋，N末端在溶液中自由扩散。两亲性螺旋的疏水侧形成胶束结合界面，并且疏水侧链延伸到胶束内部。螺旋构象的显著稳定发生在C-末端五肽中，这对于受体结合是重要的。后者得到该节段中异源NOE正值（0.52 +/- 0.1，而未连接形式为0.08 +/- 0.4）和S2值0.6 +/- 0.2（而未连接形式为0.38 +/- 0.2）的支持。胶束结合的pPYY和pNPY的结构比pPYY和bPP的结构更相似，成对RMSD分别为1.23（+/-0.21）埃或3.21（+/-0.39）埃。与DPC结合状态下的构象相似性相反，它们在溶液中的结构非常不同。事实上，pPYY更类似于bPP，其对Y-4受体的强烈偏好显示出完全不同的结合特征。考虑到pNPY和pPYY的高度序列同源性（> 80%）以及它们在所有受体亚型上的结合亲和力都很高并且更重要的是相当相似的事实，PYY和NPY更有可能从膜结合状态被Y受体识别。作为后者的结果，PP折叠对于在Y受体处识别PYY或NPY并不重要。据我们所知，这项工作提供了第一次强有力的论据来自结构数据，支持膜结合受体识别途径。(C)2004爱思唯尔有限公司保留所有权利。
Here, we investigate the structure of porcine peptide YY (pPYY) both when unligated in solution at pH 4.2 and when bound to dodecylphosphocholine (DPC) micelles at pH 5.5. pPYY in solution displays the PP-fold, with the N-terminal segment being back-folded onto the C-terminal a-helix, which extends from residue 17 to 31. In contrast to the solution structure of Keire et al. published in the year 2000 the C-terminal helix does not display a kink around residue 23-25. The root mean square deviation (RMSD) for backbone atoms of the NMR ensemble of conformers to the mean structure is 0.99 (+/-0.35) Angstrom for residues 14-31. The back-fold is supported by values of 0.60 +/- 0.1 for the N-15{H-1}-NOE and by generalized order parameters S-2 of 0.74 +/- 0.1 for residues 5-31 which indicate that the pepticle is folded in that segment. We have additionally used DPC micelles as a membrane model and determined the structure of pPYY when bound to it. Therein, an a-helix occurs in the segment comprising residues 17-31 and the N terminus freely diffuses in solution. The hydrophobic side of the amphipathic helix forms the micelle-binding interface and hydrophobic side-chains extend into the micelle interior. A significant stabilization of helical conformation occurs in the C-terminal pentapeptide, which is important for receptor binding. The latter is supported by positive values of the heteronuclear NOE in that segment (0.52 +/- 0.1 compared to 0.08 +/- 0.4 for the unligated form) and by values of S2 of 0.6 +/- 0.2 (versus 0.38 +/- 0.2 for the unligated form). The structures of micelle-bound pPYY and pNPY are much more similar than those of pPYY and bPP with pairwise RMSDs of 1.23(+/-0.21) Angstrom or 3.21 (+/-0.39) Angstrom respectively. In contrast to the conformational similarities in the DPC-bound state their structures in solution are very different. In fact pPYY is more similar to bPP, which with its strong preference for the Y-4, receptor displays a completely different binding profile. Considering the high degree of sequence homology of pNPY and pPYY (> 80%) and the fact, that their binding affinities at all receptor subtypes are high and, more importantly, rather similar, it is much more likely that PYY and NPY are recognized by the Y receptors from the membrane-bound state. As a consequence of the latter the PP-fold is not important for recognition of PYY or NPY at the Y receptors. To our knowledge this work provides for the first time strong arguments derived from structural data that support a membrane-bound receptor recognition pathway. (C) 2004 Elsevier Ltd. All rights reserved.