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Heparan N ‐sulfatase: cysteine 70 plays a role in the enzyme catalysis and processing
Author(s) -
Daniele Aurora,
Di Natale Paola
Publication year - 2001
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(01)02867-8
Subject(s) - cysteine , biochemistry , serine , enzyme , chemistry , iodoacetamide , sulfatase , active site , amino acid , mutagenesis , site directed mutagenesis , peptide sequence , mutant , stereochemistry , gene
Sulfatases are members of a highly conserved family of enzymes that catalyze the hydrolysis of sulfate ester bonds from a variety of substrates. The functional correlation reflects a high degree of amino acid sequence similarity along the entire length, in particular in the active site where the C(X)PSR consensus sequence is present. Cysteine undergoes an important co‐ or post‐translation modification essential for the accomplishment of catalytic activity: conversion in formylglycine. In this work, the cysteine of heparan N ‐sulfatase (NS) was replaced either by a serine (C70S) or by a methionine (C70M) using site‐directed mutagenesis. C70S and C70M mutant cDNAs were expressed and analyzed in COS cells; both mutations caused a loss of NS activity; however, while C70S showed a normal precursor form undergoing processing to a reduced mature form within the lysosomes, C70M was poorly synthesized and formed a complex with the molecular chaperone immunoglobulin binding protein.