Streptavidin and purification method thereof

The invention belongs to the technical field of molecular biology, and discloses streptavidin and a purification method thereof. The amino acid sequence of the streptavidin is shown as SEQ ID NO.1. The preparation method comprises the following steps: artificial gene synthesis and site-specific mutagenesis introduction, initiation codon addition, codon optimization, termination codon addition, synthesis, sequence introduction and expression, culture and purification. The streptavidin JC2 is analyzed and determined, and the JC2 is subjected to directional mutation modification to improve the biotin binding capacity of the JC2. 本发明属于分子生物学技术领域，公开了一种链霉亲和素及其纯化方法。链霉亲和素氨基酸序列如SEQ ID NO.1所示，其制备方法步骤包括：人工基因合成及定点突变引入、添加起始密码子、密码子优化、添加终止密码子、合成、序列导入及表达、培养、纯化。本发明分析并确定了链霉亲和素JC2，并且对JC2进行定向突变改造提高其结合生物素的能力。