摘要： 以口蹄疫病毒株OA/58 RNA为模板，反转录并扩增目的cDNA，然后与pGEM-T Easy载体连接并转化JM109菌株，提取的重组质粒用凝胶电泳、PCR和EcoR I酶切法鉴定。该毒株与A12，O1K，O1Campos和TW5/97毒株序列通过对比分析发现，L基因中有2个起始密码子，第二个是首选；并且确定氨基酸保守区主要位于第35～39，3～5，65～67，75～80，90～111，113～12，16～16，18～157，159～172和176～187位。L蛋白酶含有球状区域，碳端有一柔性杆状结构。合成的L蛋白酶可形成二聚体结构。第1位的Lys、18位的His和163位的Asp可能是L蛋白酶的活性位点。保守区氨基酸残基在维持蛋白的空间构像和功能方面具有重要作用。由拉马钱德兰图可证明本试验构建L蛋白酶的空间结构是合理的，它对于进一步的研究具有指导性。

关键词: 口蹄疫病毒, L蛋白酶, 活性位点

Abstract: Foot-and-mouth disease virus strain OA/58 RNAs were used as templates for RT-PCR. The amplified cDNA products were cloned into pGEM-T Easy vectors and transformed into JM109. The recombinant plasmids were identified by electrophoresis, PCR, and EcoR I cleavage. The nucleotide and amino acid sequences were compared with the L genes of the other 4 reference strains. The results show that between 2 initiation codons, there is a special function sequence which enables small subunit of ribosome to recognize and utilize the second AUG to translate L protease that is called for Lb; the regions of 35-39th, 43-54th, 65-67th, 75-80th, 90-111th, 113-142th, 144-146th, 148-157th, 159-172th and 176-187th in L protease most probably are conservative. By homology modeling the FMDV strain OA/58 L protease, the 3D mold of this protease was obtained. Resolution of the 3D structure of L protease showed a compact globular form with a flexible C terminal extension from 187th to 201th. Depending on the region of hydrophilicity residues forming hydrophilicity power, L proteases can form dimmers. Lys144, His148 and Asp163 may be active amino acids which form the active site of L protease. By Ramachandran Plot showing, 3D mold of a FMDV strain OA/58 L protease is rather reasonable, this research should be used as an instruction in order to direct the work on FMDV L protease.

Key words: FMDV, L protease, Active site

中图分类号: 

• S852.66