State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
Department of Biomedical Research, National Jewish Health, Denver, CO 80206, USA.
Viruses. 2020 Feb 14;12(2):215. doi: 10.3390/v12020215.
Porcine reproductive and respiratory syndrome virus (PRRSV) is prevalent throughout the world and has caused great economic losses to the swine industry. Nonstructural protein 10 (nsp10) is a superfamily 1 helicase participating in multiple processes of virus replication and one of the three most conserved proteins in nidoviruses. Here we report three high resolution crystal structures of highly pathogenic PRRSV nsp10. PRRSV nsp10 has multiple domains, including an N-terminal zinc-binding domain (ZBD), a β-barrel domain, a helicase core with two RecA-like domains, and a C-terminal domain (CTD). The CTD adopts a novel fold and is required for the overall structure and enzymatic activities. Although each domain except the CTD aligns well with its homologs, PRRSV nsp10 adopts an unexpected extended overall structure in crystals and solution. Moreover, structural and functional analyses of PRRSV nsp10 versus its closest homolog, equine arteritis virus nsp10, suggest that DNA binding might induce a profound conformational change of PRRSV nsp10 to exert functions, thus shedding light on the mechanisms of activity regulation of this helicase.
猪繁殖与呼吸综合征病毒（PRRSV）在全球范围内广泛流行，给养猪业造成了巨大的经济损失。非结构蛋白 10（nsp10）是参与病毒复制多个过程的超级家族 1 解旋酶，也是尼多病毒中三个最保守的蛋白之一。本研究报道了三种高致病性 PRRSV nsp10 的高分辨率晶体结构。PRRSV nsp10 具有多个结构域，包括 N 端锌结合结构域（ZBD）、β桶状结构域、具有两个 RecA 样结构域的解旋酶核心，以及 C 端结构域（CTD）。CTD 采用一种新颖的折叠方式，对于整体结构和酶活性都是必需的。尽管除 CTD 以外的每个结构域都与其同源物很好地对齐，但 PRRSV nsp10 在晶体和溶液中的整体结构呈现出出乎意料的延伸状态。此外，PRRSV nsp10 与其最接近的同源物马动脉炎病毒 nsp10 的结构和功能分析表明，DNA 结合可能会引起 PRRSV nsp10 的深刻构象变化，从而发挥作用，这为该解旋酶的活性调节机制提供了线索。
