长叶车前花叶病毒(HRV_(sh))外壳蛋白赖氨酸残基的修饰

我们曾报道长叶车前花叶病毒上海分离株(简称HRVsh)的外壳蛋白有二个赖氨酸残基,在PH8.5无变性剂存在的条件下,完整病毒颗粒表面的赖氨酸残基可与三硝基苯磺酸(TNPS)起反应,反应后的TNP-HRVsh病毒颗粒的感染力丧失达90％以上。 本文又进行了甲基乙亚胺甲酯(MEI)对HRVsh赖氨酸残基的修饰反应,修饰后的MEI-HRVsh病毒颗粒的感染力也同样丧失90％以上。 从三硝基苯磺酸修饰的病毒颗粒(TNP-HRVsh)中分离得到的RNA能与天然的HRVsh的外壳蛋白重建病毒颗粒,并具有感染力,说明修饰过程中核酸并不受影响。 进一步用同位素~(35)S,~(32)P双标记病毒,再以TNPS修饰标记的病毒,得到(~(35)S,~(32)P)-HRVsh及TNP-(~(35)S,~(32)P)-HRVsh。将两者分别接种于系统寄主青菜(Brassica chinensis)的一片叶片,一天后在非接种叶片上都可测得~(35)S,~(32)P的放射计数。其中,(~(35)S,~(32)P)-HRVsh的~(35)S/~(32)P比值降低了,而TNP-(~(35)S,~(32)P)-HRVsh的~(35)S/~(32)P比值保持不变。说明HRVsh外壳蛋白赖氨酸残基的修饰并不影响病毒颗粒进入寄主细胞,以及在寄主细胞间的转移。同位素双标记的结果表明,其感染力丧失的原因可能是由于上述修饰作用阻止了病毒在感染中所必须的脱壳过程。

MODIFICATION OF LYSINE RESIDUE OF THE COAT PROTEIN OF HOLMES' RIBGRA9S VIRUS (HRVsh)

The previous paper described that there are two lysine residues in the coatprotein of HRVsh. One of the lysine residues located on the surface of the virion of HRVsh was modified by trinitriphenylsulfonic acid under mild condition.After modification, the HRVsh nearly lost its whole infectivity.In this paper, double radioactive labeled 36S, 32P-HRVsh and TNP-modi fied '"S.'P-HRVsh were prepared. Through the infection of systemic host-Chinese cabagge ( Brassica Chinensis) with radioactive HRVsh and TNP-modified radioactive HRVsh, the result showed that both HRVsh and TNP -modified HRVsh could be transmitted to whole plant from the inoculated leaf.RNA from inactive TNP-modified HRVsh could be reconstructed with natural coat protein of HRVsh to form an active virus particles.It means that the modification of lysine residue of HRVsh does not affect on the virus RNA.The precipitate of the extract of radioactive HRVsh and TNP-modified radioactive HRVsh showed that the ratio of 35S/32P of HRVsh was changed, whereas the ratio of 35S/32P of TNP-modified HRVsh was unchanged.It was suggested that the disappearance of the infectivity of TNP-modified HRVsh may be due to the prevention of the uncoating process.