Site Specific Interaction of the Polyphenol EGCG with the SEVI Amyloid Precursor Peptide PAP(248-286)
Site Specific Interaction of the Polyphenol EGCG with the SEVI Amyloid Precursor Peptide PAP(248-286)
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DOI：
10.1021/jp2121577
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发表时间：
2012-03-22
影响因子：
3.3
通讯作者：
Ramamoorthy, Ayyalusamy
中科院分区：
文献类型：
--
作者：
Popovych, Nataliya;Brender, Jeffrey R.;Ramamoorthy, Ayyalusamy
最近，从精液中分离到一段39个氨基酸的前列腺酸性磷酸酶多肽片段，它可以使HIV病毒的传染性提高4-5个数量级。PAP(248-286)只有在聚集成称为SEVI的淀粉样纤维时才能有效地增强艾滋病毒的传染性。多酚EGCG(表没食子儿茶素没食子酸酯)已被证明能干扰SEVI的形成和SEVI对HIV的促进作用，但其完成这一任务的机制尚不清楚。在这里，我们发现EGCG在主要带电残基的两个区域(K251-R257和N269-I277)，特别是赖氨酸，与单体PAP(248-286)的侧链特异性相互作用。这两个位点的相互作用的特异性与以前关于EGCG与其他淀粉样蛋白相互作用的研究相反，后者表明EGCG与未折叠的淀粉样蛋白暴露的骨架位点之间存在非特异性相互作用。这种相互作用是EGCG所特有的，作为相关的半乳糖儿茶素(GC)分子，其抗淀粉样蛋白活性大大降低，与单体PAP(248-286)的相互作用最小。EGCG的结合分两步进行，首先形成弱结合的复合体，然后形成与pH有关的紧密结合的复合体。对PAP(248-286)的赖氨酸残基进行化学修饰的实验表明，该紧密结合的络合物是由赖氨酸残基与席夫碱形成的。这项研究的结果可能有助于开发SEVI和其他淀粉样蛋白的小分子抑制剂。
Recently, a 39 amino acid peptide fragment from prostatic acid phosphatase has been isolated from seminal fluid that can enhance infectivity of the HIV virus by up to 4-5 orders of magnitude. PAP(248-286) is effective in enhancing HIV infectivity only when it is aggregated into amyloid fibers termed SEVI. The polyphenol EGCG (epigallocatechin-3-gallate) has been shown to disrupt both SEVI formation and HIV promotion by SEVI, but the mechanism by which it accomplishes this task is unknown. Here, we show that EGCG interacts specifically with the side chains of monomeric PAP(248-286) in two regions (K251-R257 and N269-I277) of primarily charged residues, particularly lysine. The specificity of interaction to these two sites is contrary to previous studies on the interaction of EGCG with other amyloidogenic proteins, which showed the nonspecific interaction of EGCG with exposed backbone sites of unfolded amyloidogenic proteins. This interaction is specific to EGCG as the related gallocatechin (GC) molecule, which shows greatly decreased antiamyloid activity, exhibits minimal interaction with monomeric PAP(248-286). The EGCG binding was shown to occur in two steps, with the initial formation of a weakly bound complex followed by a pH dependent formation of a tightly bound complex. Experiments in which the lysine residues of PAP(248-286) have been chemically modified suggest the tightly bound complex is created by Schiff-base formation with lysine residues. The results of this study could aid in the development of small molecule inhibitors of SEVI and other amyloid proteins.