中文摘要：

为构建抗黄曲霉毒素M1单链抗体（seFv）基因，并进行蛋白质结构模拟及理化特性分析。采用重叠延伸PCR方法，以能特异性分泌抗黄曲霉毒素M1单克隆抗体的杂交瘤细胞株1812为原料，构建其单链抗体基因，进行测序，采用生物信息软件进行氨基酸序列推导、结构预测以及理化性质分析。抗黄曲霉毒素M1seFv基因全长737bp，对应245个氨基酸，单链抗体分子量约为25897．4，等电点预测值6．90；二级结构显示抗黄曲霉毒素M。单链抗体含a螺旋38处，卢折叠24处，延伸链74处，随机卷曲109处。三级结构建模显示重链（VH）和轻链（VL）的6个环区（CDR区），共同组成抗体的抗原结合区，符合scFv的结构特点，具有抗原结合位点的空间构象。构建了一个抗黄曲霉毒素M1scFv基因，应用生物信息学技术所获得的预测和分析结果为该单链抗体的进一步表达、纯化和活性研究提供信息。

英文摘要：

To construct the gene of single chain Fv （scFv） fragment against aflatoxin M1 ,to predict secondary and tertia- ry structures of its encoding protein by computer assisted modeling and to analyze its physical and chemical properties. The gene of anti-afiatoxin M1 scFv was constructed with I B12 hybridoma cells that is able to secret monoclonal antibodies （mAb） with high activity and specificity against aflatoxin M1 as the raw material, and sequenced by splicing overlap exten- sion（SOE） PCR assay. Furthermore,its amino acid sequence was deduced and the secondary and tertiary structures were predicted using biological information software. Meanwhile, its physical and chemical properties were analyzed. The full- length scFv gene had 737 bp and encoded 245 amino acids. The relative molecular weight of the scFv was 25 897.4, its predictive isoelectric point（pl） was 6. 90. The predicted sec- ondary structure indicated that the protein contained 38 α-he- lix,24 β-sheet,74 extended strand and 109 random coli. The mimic tertiary structure model of the scFv indicted that all the six CDRs of VL and VH were contribute to the antlgen-bind- ing site. The successful construction of a scFv gene against af- latoxin M1 can laid the foundation for the further research into the expression, purification and bioactivity of genetic engi- neering antibody.