Structure of coronavirus main proteinase reveals combination of a chymotrypsin fold with an extra alpha-helical domain.
Structure of coronavirus main proteinase reveals combination of a chymotrypsin fold with an extra alpha-helical domain.
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冠状病毒主蛋白酶的结构揭示了甲over依蛋白酶折叠与额外的α-螺旋结构域的组合。
DOI：
10.1093/emboj/cdf327
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发表时间：
2002-07-01
期刊：
影响因子：
11.4
通讯作者：
Hilgenfeld, Rolf
中科院分区：
文献类型：
--
作者：
Anand, Kanchan;Palm, Gottfried J;Mesters, Jeroen R;Siddell, Stuart G;Ziebuhr, John;Hilgenfeld, Rolf
冠状病毒多蛋白加工中的关键酶是病毒主要蛋白酶，MPRO，一种与其他病毒和细胞蛋白酶序列相似性极低的蛋白质。在这里，报道了33.1 kDa传染性胃肠炎(冠状)病毒MPRO的晶体结构。结构被细化到1.96%Å分辨率，并在不对称单元中显示了三个二聚体。每个二聚体中的原型相互排列表明，MPRO的自我处理发生在反式中。活性部位由Cys144和His41组成，是类糜蛋白酶折叠的一部分，该折叠通过一个16位残基环连接到一个具有新的α-螺旋折叠的额外结构域。分子模拟和突变数据表明，该环与底物结合，并阐明了S1和S2亚基适合容纳MPRO底物的P1谷氨酰胺和P2亮氨酸残基的侧链。涉及N-末端和α-螺旋结构域的相互作用使环稳定在反式切割活动所需的方向上。这项研究表明，RNA病毒已经进化出了经典胰凝乳酶折叠的前所未有的变异。
The key enzyme in coronavirus polyprotein processing is the viral main proteinase, Mpro, a protein with extremely low sequence similarity to other viral and cellular proteinases. Here, the crystal structure of the 33.1 kDa transmissible gastroenteritis (corona)virus Mpro is reported. The structure was refined to 1.96 Å resolution and revealed three dimers in the asymmetric unit. The mutual arrangement of the protomers in each of the dimers suggests that Mpro self-processing occurs in trans. The active site, comprised of Cys144 and His41, is part of a chymotrypsin-like fold that is connected by a 16 residue loop to an extra domain featuring a novel α-helical fold. Molecular modelling and mutagenesis data implicate the loop in substrate binding and elucidate S1 and S2 subsites suitable to accommodate the side chains of the P1 glutamine and P2 leucine residues of Mpro substrates. Interactions involving the N-terminus and the α-helical domain stabilize the loop in the orientation required for trans-cleavage activity. The study illustrates that RNA viruses have evolved unprecedented variations of the classical chymotrypsin fold.