β-折叠破坏肽 16-23 和 17-24 逆转淀粉样β肽 Abeta40 的温度诱导构象变化。

Reversal of temperature-induced conformational changes in the amyloid-beta peptide, Abeta40, by the beta-sheet breaker peptides 16-23 and 17-24.

机构信息

Department of Pharmacology, Division of Internal Medicine, Faculty of Medicine, Pamukkale University, Kinikli Campus, Denizli, Turkey.

出版信息

Br J Pharmacol. 2009 Oct;158(4):1165-72. doi: 10.1111/j.1476-5381.2009.00384.x. Epub 2009 Sep 25.

DOI:10.1111/j.1476-5381.2009.00384.x

PMID:19785651

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC2785537/

Abstract

BACKGROUND AND PURPOSE

Aggregates of the protein amyloid-beta (Abeta) play a crucial role in the pathogenesis of Alzheimer's disease (AD). Most therapeutic approaches to AD do not target Abeta, so determination of the factor(s) that facilitate aggregation and discovering agents that prevent aggregation have great potential therapeutic value.

EXPERIMENTAL APPROACH

We investigated ex vivo the temperature-sensitive regions of Abeta1-40 (Abeta40) and their interactions with octapeptides derived from sequences within Abeta40 -beta-sheet breaker peptides (betaSBP) - using enzyme-linked immunosorbent assay, and dot blot and far-UV circular dichroism (CD) spectroscopy. We measured changes within the physiological limits of temperature, using antibodies targeting epitopes 1-7, 5-10, 9-14 and 17-21 within Abeta40.

KEY RESULTS

Temperature-dependent conformational changes were observed in Abeta40 at epitopes 9-14 and 17-21 at 36-38 and 36-40 degrees C respectively. The betaSBPs 16-23 and 17-24, but not 15-22 and 18-25, could inhibit the changes. Moreover, betaSBPs 16-23 and 17-24 increased digestion of Abeta40 by protease K, indicating a decreased aggregation of Abeta40, whereas betaSBPs 15-22 and 18-25 did not increase this digestion. CD spectra revealed that beta-sheet formation in Abeta40 at 38 degrees C was reduced with betaSBPs 16-23 and 17-24.

CONCLUSIONS AND IMPLICATIONS

The epitopes 9-14 and 17-21 are the temperature-sensitive regions within Abeta40. The betaSBPs, Abeta16-23 and 17-24 reversed temperature-induced beta-sheet formation, and decreased Abeta40 aggregation. The results suggest that the 17-23 epitope of Abeta40 is crucially involved in preventing Abeta40 aggregation and consequent deposition of Abeta40 in AD brain.

摘要

背景与目的

蛋白淀粉样-β（Abeta）的聚集体在阿尔茨海默病（AD）的发病机制中起着至关重要的作用。大多数 AD 的治疗方法都不针对 Abeta，因此确定促进聚集的因素并发现防止聚集的药物具有巨大的潜在治疗价值。

实验方法

我们使用酶联免疫吸附试验、点印迹和远紫外圆二色性（CD）光谱法，研究了 Abeta1-40（Abeta40）的温度敏感区域及其与 Abeta40-β-断裂肽（βSBP）中的八肽的相互作用。我们使用针对 Abeta40 中的表位 1-7、5-10、9-14 和 17-21 的抗体，在生理温度范围内进行了测量。

主要结果

在 Abeta40 的表位 9-14 和 17-21 处观察到温度依赖性构象变化，分别在 36-38 和 36-40°C。βSBPs 16-23 和 17-24 但不是 15-22 和 18-25 可以抑制这些变化。此外，βSBPs 16-23 和 17-24 增加了蛋白酶 K 对 Abeta40 的消化，表明 Abeta40 的聚集减少，而βSBPs 15-22 和 18-25 并没有增加这种消化。CD 光谱表明，在 38°C 时，Abeta40 中的β-折叠形成减少了与βSBPs 16-23 和 17-24 的结合。

结论和意义

表位 9-14 和 17-21 是 Abeta40 中的温度敏感区域。βSBPs，Abeta16-23 和 17-24 逆转了温度诱导的β-折叠形成，并减少了 Abeta40 的聚集。结果表明，Abeta40 的 17-23 表位对于防止 Abeta40 聚集以及随后在 AD 脑中 Abeta40 的沉积至关重要。