Dermody T S, Nibert M L, Bassel-Duby R, Fields B N
Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115.
J Virol. 1990 Oct;64(10):5173-6. doi: 10.1128/JVI.64.10.5173-5176.1990.
Hemagglutination (HA) by the mammalian reoviruses is mediated by interactions between the viral sigma 1 protein and sialoglycoproteins on the erythrocyte surface. Three serotype 3 (T3) reovirus strains were identified that do not agglutinate either bovine or type O human erythrocytes (HA negative): T3 clone 43 (T3C43), T3 clone 44 (T3C44), and T3 clone 84 (T3C84). These three strains also showed a diminished capacity to bind the major erythrocyte sialoglycoprotein, glycophorin, in an enzyme-linked immunosorbent assay. To determine the molecular basis for these findings, we examined the deduced sigma 1 amino acid sequences of the three HA-negative T3 strains and four HA-positive T3 strains. The limited number of sequence differences in the sigma 1 proteins of these seven strains allowed us to identify single unique amino acid residues in each of the HA-negative strains (aspartate 198 in T3C43, leucine 204 in T3C44, and tryptophan 202 in T3C84) that cluster within a discrete region of the sigma 1 tail. The identification of sigma 1 residues important for HA and glycophorin binding suggests that tail-forming sequences are exposed on the virion surface, where they interact with carbohydrate residues on the surface of cells.
哺乳动物呼肠孤病毒的血细胞凝集（HA）作用是由病毒σ1蛋白与红细胞表面的唾液酸糖蛋白之间的相互作用介导的。已鉴定出三种3型（T3）呼肠孤病毒株不凝集牛或O型人红细胞（HA阴性）：T3克隆43（T3C43）、T3克隆44（T3C44）和T3克隆84（T3C84）。在酶联免疫吸附测定中，这三种毒株与主要红细胞唾液酸糖蛋白血型糖蛋白的结合能力也有所下降。为了确定这些发现的分子基础，我们检查了三种HA阴性T3毒株和四种HA阳性T3毒株推导的σ1氨基酸序列。这七种毒株的σ1蛋白中有限数量的序列差异使我们能够在每个HA阴性毒株中鉴定出单个独特的氨基酸残基（T3C43中的天冬氨酸198、T3C44中的亮氨酸204和T3C84中的色氨酸202），这些残基聚集在σ1尾部的一个离散区域内。对HA和血型糖蛋白结合重要的σ1残基的鉴定表明，形成尾部的序列暴露在病毒粒子表面，在那里它们与细胞表面的碳水化合物残基相互作用。
