Structural Organization of the Active Center of Unmodified Recombinant Sulfatase from the Mycelial Fungi Fusarium proliferatum LE1

— 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.