[Objective] This study aimed to reconstruct the HP intein by overlap-exten- sion PCR. [Method] Several primers were designed according to the principle of overlap-extension PCR that the repeat sequences were overlapped and served as the template to the other DNA strand in amplification. Then, several rounds of over- lap PCR reaction were conducted to mutate the four cysteines in the HP intein into serines, and introduce a linker sequence containing a tag for product detection and purification. [Result] DNA sequencing analysis proved that the four cysteines in the HP intein were successfully mutated into serines; the PCR precursor fragments were also rejoined into an intact HP gene fragment, without introducing any other unex- pected mutation; the DNA linker of 46 bp was successfully inserted into the de- signed HP gene sequences, without any mutation and base pair mismatch. [Conclu- sion] The HP intein was rapidly reconstructed by overlap-extension PCR in this study, which not only expands the application of overlap PCR in protein engineering, but also provides a simple, efficient and highly accurate tool for the reconstruction and modification of intein.
由蛋白质内含子介导的亲和蛋白质纯化系统(IMPACT)已得到广泛应用,通过其纯化得到的目的蛋白不含蛋白纯化标签以及多余的氨基酸残基,且操作简单成本低廉。这些优点使得其相对于其他蛋白纯化系统有着无与伦比的优势。但是现有报道都局限于非变性条件下使用,这往往会限制其在一些包涵体蛋白变性条件下使用。以一已知表达形成包涵体形式的丝素蛋白为例,研究IMPACT系统在时变性条件下使用变性剂浓度、温度和诱导断裂还原剂浓度。实验表明,在4 M尿素,100 mM DTT室温作用下蛋白质内含子会获得最大断裂效率(80%)。柱上在线断裂实验表明,其最终蛋白得率超过65%。
