Donghua University, Shanghai, People's Republic of China.
Curr Microbiol. 2010 Jun;60(6):461-5. doi: 10.1007/s00284-009-9565-x. Epub 2009 Dec 23.
O-acetylserine sulfhydrylase (OASS) is a key enzyme involved in the pathway of the cysteine biosynthesis. The gene of OASS from Acidithiobacillus ferrooxidans ATCC 23270 was cloned and expressed in E. coli, the soluble protein was purified by one-step affinity chromatography to apparent homogeneity. Colors and UV-vis scanning results of the recombinant protein confirmed that it was a pyridoxal 5'-phosphate (PLP)-containing protein. Sequence alignment and site-directed mutation of the enzyme revealed that the cofactor PLP is covalently bound in Schiff base linkage with K30, as well as the two residues H150 and H168 were the crucial residues for PLP binding and stabilization.
O-乙酰丝氨酸巯基酶（OASS）是半胱氨酸生物合成途径中的关键酶。从氧化亚铁硫杆菌 ATCC 23270 中克隆并在大肠杆菌中表达了 OASS 基因，通过一步亲和层析将可溶性蛋白纯化至明显均一。重组蛋白的颜色和 UV-vis 扫描结果证实它是一种含有吡哆醛 5'-磷酸（PLP）的蛋白质。酶的序列比对和定点突变表明，辅因子 PLP 通过希夫碱键与 K30 共价结合，并且 H150 和 H168 两个残基是 PLP 结合和稳定的关键残基。
