酿酒酵母ATP-硫酸化酶在大肠杆菌中的表达纯化及其在焦测序中的应用

Expression and Purification of ATP Sulfurylase from Saccharomyces cerevisias in Escherichia coli and Its Application in Pyrosequencing

ATP-硫酸化酶(ATPS,EC2.7.7.4)是一种可逆催化ATP和SO42-反应生成腺嘌呤-5′-磷酸硫酸(APS)和焦磷酸盐(PPi)的酶,已经用于焦测序反应。以酿酒酵母(Saccharomyces cerevisias,CICC1202)基因组DNA为模板,用PCR扩增得到ATPS基因,并克隆到原核表达质粒pET28a(+),得到重组表达质粒pET28a(+)-ATPS,在IPTG诱导下,携带pET28a(+)-ATPS的大肠杆菌BL21(DE3)表达分子量约为60kD的带有His标签的ATPS酶,经镍亲和层析和超滤两步纯化后,可得到电泳纯级ATPS,比活达5.1×104u/mg,并成功应用于焦测序反应中。

ATP sulfurylase （ATPS, EC 2.7.7.4） reversibly catalyzes the reaction between ATP and sulfate to produce AlaS and pyrophosphate（PPi）, and has been used in pyrosequencing. The gene coding ATP sulfurylase was amplified from the genomic DNA of Saccharomyces cerevisias （CICC 1202）, and cloned into prokaryntic expression plasmid pET28a （ ＋ ） to provide a recombinant expression plasmid pET28a（ ＋ ）-ATPS. Upon IPTG induction, ATP sulfurylase was produced by E. coli BL21 （DE3） harboring the recombinant expression plasmid pET28a（ ＋ ）-ATPS. The relative molecular weight of recombinant ATP sulfurylase with His tag was about 60kD. The recombinant ATP sulfurylase with electrophoretic pure grade was obtained only by two purification steps： His-Bind Resin affinity chromatography and uhrafiltration. The specific activity of the purified recombinant ATP sulfurylase was as high as 5.1 ×10^4 u/mg. The successful application of the enzyme in pyrosequencing was also demostrated.