Sulfatases catalyze the hydrolysis of sulfuric acid esters and play a key role in a number of biological processes of both higher eukaryotes and prokaryotes. According to literature data, for the implementation of catalysis, some representatives of this group of enzymes require posttranslational modification of serine or cysteine residues in the active center into the unique amino acid Cα-formylglycine. Nevertheless, it is confirmed that even in the absence of this modification, some sulfatases are capable of catalyzing the hydrolysis of sulfoesters. In this work, we studied the structural and functional features of active recombinant sulfatase from the mycelial fungus Fusarium proliferatum LE1, which contains a cysteine residue in the active center. A theoretical atomic model of the enzyme was first constructed, the structural organization of its active center was determined, and key amino acid residues involved in the binding of p-nitrophenyl sulfate and in the reaction of its hydrolysis were identified. Point amino acid substitutions of the identified residues led to inactivation of the enzyme. In particular, mutant forms of the enzyme with the replacement of catalytic cysteine by serine and threonine containing a hydroxyl group in the side chain completely lost activity, which indicates the direct participation of the mercapto group of cysteine in the hydrolysis reaction.

中文翻译：

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来自菌丝体增殖镰刀菌 LE1 的未修饰重组硫酸酯酶活性中心的结构组织

硫酸酯酶催化硫酸酯的水解，并在高等真核生物和原核生物的许多生物过程中起关键作用。根据文献资料，为实现催化作用，该组酶的一些代表需要将活性中心的丝氨酸或半胱氨酸残基翻译后修饰成独特的氨基酸Cα-甲酰基甘氨酸。尽管如此，已经证实即使没有这种修饰，一些硫酸酯酶也能够催化磺基酯的水解。在这项工作中，我们研究了来自菌丝体 Fusarium proliferatum LE1 的活性重组硫酸酯酶的结构和功能特征，其活性中心含有一个半胱氨酸残基。首先构建了酶的理论原子模型，确定了其活性中心的结构组织，并确定了参与对硝基苯硫酸盐结合及其水解反应的关键氨基酸残基。已鉴定残基的点氨基酸取代导致酶失活。特别是，催化半胱氨酸被侧链中含有羟基的丝氨酸和苏氨酸取代的酶的突变形式完全失去活性，这表明半胱氨酸的巯基直接参与水解反应。