Long-range cooperative interactions modulate dimerization in SARS 3CLpro
Long-range cooperative interactions modulate dimerization in SARS 3CLpro
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DOI：
10.1021/bi0616302
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发表时间：
2006-12-19
期刊：
影响因子：
2.9
通讯作者：
Freire, Ernesto
中科院分区：
文献类型：
--
作者：
Barrila, Jennifer;Bacha, Usman;Freire, Ernesto
严重急性呼吸综合征（SARS）是由人类冠状病毒（SARS-CoV）引起的一种传染病。主要的病毒蛋白酶SARS 3CL（pro）是开发抗病毒疗法的有效靶点。由于酶是一种同源二聚体，并且单个单体是无活性的，因此使用两种方法来开发抑制剂：靶向活性位点的酶活性抑制剂和二聚化抑制剂。二聚化抑制剂通常靶向二聚化界面，并且需要与亚基之间的吸引力竞争才有效。在本文中，我们表明，SARS 3CLpro的二聚化也在变构控制下，并且远离二聚化界面的额外的和能量上更有利的靶位点也可能导致亚基解离。我们先前鉴定了位于3CLpro的活性位点附近的一簇保守丝氨酸残基（Ser 139、Ser 144和Ser 147），其可以有效地靶向于抑制蛋白酶[Bacha，U等人（2004）Biochemistry 43，4906-4912]。这些丝氨酸残基中的任何一个突变为丙氨酸对3CLpro的催化活性具有削弱作用。特别地，Ser 147的突变，其不与相对亚基进行任何接触，并且位于距离二聚体界面约9埃处，完全抑制二聚化，并导致酶活性的完全丧失。远离二聚体界面的残基能够控制二聚化的发现定义了用于设计二聚化抑制剂的替代靶标。
Severe acute respiratory syndrome (SARS) is an infectious disease caused by the human coronavirus, SARS-CoV. The main viral protease, SARS 3CL(pro), is a validated target for the development of antiviral therapies. Since the enzyme is a homodimer and the individual monomers are inactive, two approaches are being used to develop inhibitors: enzyme activity inhibitors that target the active site and dimerization inhibitors. Dimerization inhibitors are usually targeted to the dimerization interface and need to compete with the attractive forces between subunits to be effective. In this paper, we show that the dimerization of SARS 3CLpro is also under allosteric control and that additional and energetically more favorable target sites away from the dimerization interface may also lead to subunit dissociation. We previously identified a cluster of conserved serine residues (Ser139, Ser144, and Ser147) located adjacent to the active site of 3CLpro that could effectively be targeted to inactivate the protease [Bacha, U et al. (2004) Biochemistry 43, 4906-4912]. Mutation of any of these serine residues to alanine had a debilitating effect on the catalytic activity of 3CLpro. In particular, the mutation of Ser147, which does not make any contact with the opposing subunit and is located approximately 9 angstrom away from the dimer interface, totally inhibited dimerization and resulted in a complete loss of enzymatic activity. The finding that residues away from the dimer interface are able to control dimerization defines alternative targets for the design of dimerization inhibitors.