Santos-López Gerardo, Borraz-Argüello María T, Márquez-Domínguez Luis, Flores-Alonso Juan Carlos, Ramírez-Mendoza Humberto, Priem Bernard, Fort Sébastien, Vallejo-Ruiz Verónica, Reyes-Leyva Julio, Herrera-Camacho Irma
Laboratorio de Biología Molecular y Virología, Centro de Investigación Biomédica de Oriente, Instituto Mexicano del Seguro Social, Metepec, Puebla, Mexico.
Departamento de Ingeniería en Biotecnología Universidad Politécnica de Puebla, Calpan, Puebla, Mexico.
Res Vet Sci. 2017 Oct;114:218-224. doi: 10.1016/j.rvsc.2017.05.008. Epub 2017 May 6.
Porcine rubulavirus (PorPV), also known as La Piedad Michoacan Virus (LPMV) causes encephalitis and reproductive failure in newborn and adult pigs, respectively. The hemagglutinin-neuraminidase (HN) glycoprotein is the most exposed and antigenic of the virus proteins. HN plays central roles in PorPV infection; i.e., it recognizes sialic acid-containing cell receptors that mediate virus attachment and penetration; in addition, its neuraminidase (sialic acid releasing) activity has been proposed as a virulence factor. This work describes the purification and characterization of PorPV HN protein (isolate PAC1). The specificity of neuraminidase is restricted to sialyl(α2,3)lactose (3SL). HN showed typical Michaelis-Menten kinetics with fetuin as substrate (km=0.029μM, Vmax=522.8nmolminmg). When 3SL was used as substrate, typical cooperative kinetics were found (S=0.15μM, Vmax=154.3nmolminmg). The influenza inhibitor zanamivir inhibited the PorPV neuraminidase with IC of 0.24μM. PorPV neuraminidase was activated by Ca and inhibited by nucleoside triphosphates with the level of inhibition depending on phosphorylation level. The present results open possibilities to study the role of neuraminidase in the pathogenicity of PorPV infection and its potential inhibitors.
猪腮腺炎病毒（PorPV），也被称为米却肯州拉皮德城病毒（LPMV），分别在新生仔猪和成年猪中引起脑炎和繁殖障碍。血凝素神经氨酸酶（HN）糖蛋白是病毒蛋白中暴露程度最高且具有抗原性的蛋白。HN在PorPV感染中起核心作用；也就是说，它识别含唾液酸的细胞受体，介导病毒的附着和穿透；此外，其神经氨酸酶（释放唾液酸）活性被认为是一种毒力因子。这项工作描述了PorPV HN蛋白（分离株PAC1）的纯化和特性。神经氨酸酶的特异性仅限于唾液酸（α2,3）乳糖（3SL）。以胎球蛋白为底物时，HN表现出典型的米氏动力学（km = 0.029μM，Vmax = 522.8nmol/min·mg）。当使用3SL作为底物时，发现典型的协同动力学（S = 0.15μM，Vmax = 154.3nmol/min·mg）。流感抑制剂扎那米韦以0.24μM的IC抑制PorPV神经氨酸酶。PorPV神经氨酸酶被Ca激活，并被核苷三磷酸抑制，抑制水平取决于磷酸化水平。目前的结果为研究神经氨酸酶在PorPV感染致病性中的作用及其潜在抑制剂提供了可能性。
