Hydrophilic peptides derived from the transframe region of Gag-Pol inhibit the HIV-1 protease
Hydrophilic peptides derived from the transframe region of Gag-Pol inhibit the HIV-1 protease
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DOI：
10.1021/bi972059x
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发表时间：
1998-02-24
期刊：
影响因子：
2.9
通讯作者：
Davies, DR
中科院分区：
文献类型：
--
作者：
Louis, JM;Dyda, F;Davies, DR
HIV-1跨框区（transframe region，TFR）位于Gag-Pol多聚蛋白的结构域和功能域之间，其N端和C端分别为核衣壳和蛋白酶结构域。跨框八肽（Transframe octapeptide，TFP）Phe-Leu-Arg-Glu-Asp-Leu-Ala-Phe，TFR的N端及其类似物是成熟HIV-1蛋白酶作用的竞争性抑制剂。最小、最有效的类似物是三肽：Glu-Asp-Leu和Glu-Asp-Phe的Ki值分别接近50和20 μ M，TFP中的酸性氨基酸被中性氨基酸和Glu-Asp-Leu的D或反D构型取代导致Ki增加>40倍，Glu-Asp-Leu对蛋白酶的抑制作用依赖于pK（a）为3.8的基团的质子化形式;与其它高度疏水的HIV-1蛋白酶抑制剂不同，Glu-Asp-Leu极溶于水，并且其结合亲和力随NaCl浓度的增加而降低。然而，Glu-Asp-Leu是哺乳动物天冬氨酸蛋白酶胃蛋白酶的不良抑制剂（K-1类似于7.5 mM）。在pH4.2的条件下，用X-射线晶体学方法研究了Glu-Asp-Leu的P2位Glu和P1位Leu与HIV-1蛋白酶活性位点残基的相互作用，结果表明，它们与其它产物-酶复合物的作用类似。病毒TFP对HIV-1蛋白酶的序列特异性选择性抑制表明TFP在HIV-1复制过程中调节蛋白酶功能的作用。
The HIV-1 transframe region (TFR) is between the structural and functional domains of the Gag-Pol polyprotein, flanked by the nucleocapsid and the protease domains at its N and C termini, respectively, Transframe octapeptide (TFP) Phe-Leu-Arg-Glu-Asp-Leu-Ala-Phe, the N terminus of TFR, and its analogues are competitive inhibitors of the action of the mature HIV-1 protease. The smallest, most potent analogues are tripeptides: Glu-Asp-Leu and Glu-Asp-Phe with K-i values of similar to 50 and similar to 20 mu M, respectively, Substitution of the acidic amino acids in the TFP by neutral amino acids and D or retro-D configurations of Glu-Asp-Leu results in an >40-fold increase in K-i, Protease inhibition by Glu-Asp-Leu is dependent on a protonated form of a group with a pK(a), of 3.8; unlike other inhibitors of HIV-I protease which are highly hydrophobic, Glu-Asp-Leu is extremely soluble in water, and its binding affinity decreases with increasing NaCl concentration. However, Glu-Asp-Leu is a poor inhibitor (K-1 similar to 7.5 mM) of the mammalian;aspartic acid protease pepsin. X-ray crystallographic studies at pH 4.2 show that the interactions of Glu at P2 and Leu at P1 of Glu-Asp-Leu with residues of the active site of HIV-1 protease are similar to those of other product-enzyme complexes, It was not feasible to understand the interaction of intact TFP with HIV-1 protease under conditions of crystal growth due to its hydrolysis giving rise to two products. The sequence-specific, selective inhibition of the HIV-1 protease by the viral TFP suggests a role for TFP in regulating protease function during HIV-I replication.