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

ATP sulfurylase (ATPS, C 2.7.7.4) reversibly catalyzes the reaction between ATP and sulfate to produce APS 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 prokaryotic 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 60 kD. Including the extra desalting step, only two purification steps are required to obtain the recombinant ATPS with electrophoretic pure grade. The specific activity of the purified recombinant ATP sulfurylase was as high as 5.1×104 u/mg. The successful application of the enzyme in pyrosequencing was also demonstrated