Membrane Interaction of Disease-Related Dynorphin A Variants
Membrane Interaction of Disease-Related Dynorphin A Variants
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DOI：
10.1021/bi4004205
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发表时间：
2013-06-18
期刊：
影响因子：
2.9
通讯作者：
Maier, Lena
中科院分区：
文献类型：
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作者：
Bjorneras, Johannes;Graslund, Astrid;Maier, Lena
用圆二色谱（CD）和核磁共振（NMR）研究了神经肽强啡肽A（DynA）的两个单残基变体R6 W和L5 S的膜相互作用性质。最近在人类中发现了相应的基因突变，并与神经退行性疾病有因果关系。在缓冲液和q = 0.3的具有1，2-二肉豆蔻酰-sn-甘油基-3-磷酸胆碱（DMPC）或DMPC（0.8）和1，2-二肉豆蔻酰-sn-甘油基-3-磷酸（1 '-rac-甘油）（DMPG）（0.2）的双胞的各向同性溶液中研究肽。CD结果和NMR二级化学位移表明，R6 W-DynA在缓冲液中具有小的α-螺旋部分，其在双胞的存在下增加，而L5 S-DynA在这里研究的所有条件下主要是非结构化的。R6 W-DynA与两性离子双胞具有几乎完全的缔合（类似于90%，如通过NMR扩散实验探测的），类似于wtDynA的行为，而L5 S-DynA具有较弱的缔合（类似于50%）。对于所有肽，在带负电荷的双胞中双胞缔合的水平增加。的L5 A-DynA肽采用一个非常浅的位置在头基区的bicelle双层，研究顺磁自旋弛豫增强实验，使用顺磁探针。类似地，结果显示R6 W-DynA更深地埋在双层中，仅C-末端残基暴露于溶剂，再次与野生型DynA的情况更相似。我们认为，这里提出的结果可以解释这些疾病相关的神经肽变异体的细胞毒性的差异。
The membrane interaction properties of two single-residue variants, R6W and L5S, of the 17-amino acid neuropeptide dynorphin A (DynA) were studied by circular dichroism (CD) and nuclear magnetic resonance (NMR) spectroscopy. Corresponding gene mutations have recently been discovered in humans and causatively linked to a neurodegenerative disorder. The peptides were investigated in buffer and in isotropic solutions of q = 0.3 bicelles with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) or DMPC (0.8) and 1,2-dimyristoyl-sn-glycero-3-phospho(1'-rac-glycerol) (DMPG) (0.2). The CD results and the NMR secondary chemical shifts show that R6W-DynA has a small a-helical fraction in buffer, which increases in the presence of bicelles, while L5S-DynA is mainly unstructured under all conditions studied here. R6W-DynA has an almost complete association with zwitterionic bicelles (similar to 90%, as probed by NMR diffusion experiments), similar to the behavior of wtDynA, while L5S-DynA has a weaker association (similar to 50%). For all peptides, the level of bicelle association is increased in negatively charged bicelles. The L5A-DynA peptide adopts a very shallow position in the headgroup region of the bicelle bilayer, as studied by paramagnetic spin relaxation enhancement experiments using paramagnetic probes. Similarly, the results show that R6W-DynA is more deeply buried in the bilayer, with only the C-terminal residues exposed to solvent, again more similar to the case of wild-type DynA. We suggest that the results presented here may explain the differences in cell toxicity of these disease-related neuropeptide variants.