Application | Comment | Organism |
---|---|---|
drug development | the enzyme is a target for the development of structure-based drug design for the devastating neurodegenerative disorder mucopolysaccharidosis type IIIA or Sanfilippo A syndrome | Homo sapiens |
Cloned (Comment) | Organism |
---|---|
recombinant expression of C-terminally His6-tagged full-length enzyme in HEK-293 cells | Homo sapiens |
Crystallization (Comment) | Organism |
---|---|
purified recombinant C-terminally His6-tagged, glycosylated full-length enzyme, small unit and large unit crystal forms, X-ray diffraction structure determination and analysis at 2.0-2.4 A resolution, molecular replacement. The enzyme appears to exist as a homodimer in both crystal forms | Homo sapiens |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
phosphate | - |
Homo sapiens | |
sulfate | - |
Homo sapiens |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Homo sapiens | P51688 | - |
- |
Posttranslational Modification | Comment | Organism |
---|---|---|
glycoprotein | Asn41, Asn151, Asn264 and Asn413 are four of the five N-glycosylation sites | Homo sapiens |
Purification (Comment) | Organism |
---|---|
recombinant C-terminally His6-tagged full-length enzyme from HEK-293 cells by nickel affinity croomatography | Homo sapiens |
Reaction | Comment | Organism | Reaction ID |
---|---|---|---|
N-sulfo-D-glucosamine + H2O = D-glucosamine + sulfate | catalytic reaction mechanism: the active-site formylglycine (FGly70), which is intrinsically reactive, undergoes hydration to form the resting state of the enzyme with a gem-diol group (step 1). Coordination of one of the hydroxyl groups of the gem-diol to a Ca2+ ion facilitates the development of a negative charge on the O atom as its proton is lost to a base. The negatively charged O atom nucleophilically attacks the sulfur centre of the N-linked sulfate group on the glucosamine substrate (step 2), resulting in a covalently bound enzyme-substrate complex with a pentavalent sulfur transition state. An acid (possibly His181) facilitates the cleavage of the S-N bond by protonating the bridging N atom to form an amine leaving group on the N-desulfated substrate, which diffuses away, leaving an O-sulfated enzyme (step 3). Finally, in a step that underlines the importance of the formylglycine residue, another base (His125) deprotonates the second hydroxyl group, resulting in a negatively charged O atom (step 4) that forms a double bond with the C atom as the C-O bond between it and the bridging O atom of the sulfate group breaks, eliminating the sulfate ion and regenerating the formylglycine residue (step 5) | Homo sapiens |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
4-methylumbelliferyl-alpha-D-N-sulfoglucosaminide + H2O | - |
Homo sapiens | 4-methylumbelliferyl alpha-D-glucosaminide + sulfate | - |
? | |
additional information | the enzymatic activity of the enzyme is measured in a two-step reaction: 4-methylumbelliferyl-alpha-D-N-sulfoglucosaminide is desulfated by the enzyme to become a substrate for alpha-glucosidase, which converts 4-methylumbelliferyl-alpha-D-N-sulfoglucosamine to methylumbelliferone, which is a fluorescent compound | Homo sapiens | ? | - |
? |
Subunits | Comment | Organism |
---|---|---|
homodimer | recombinant enzyme, crystal structure analysis. Two SGSH monomers associate noncovalently to form a butterfly-shaped homodimer burying approximately 10.3% of the accessible surface area of each subunit | Homo sapiens |
More | the monomeric enzyme subunit comprises of two domains, each centred on a beta-sheet: a large N-terminal domain (domain 1) and a smaller C-terminal domain (domain 2), as is typical for the sulfatase fold. There are 14 beta-strands, 13 alpha-helices and six 310-helices (T1-T6) in total | Homo sapiens |
Synonyms | Comment | Organism |
---|---|---|
SGSH | - |
Homo sapiens |
sulfamate sulfohydrolase | - |
Homo sapiens |
sulfamidase | - |
Homo sapiens |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
37 | - |
assay at | Homo sapiens |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
6.7 | - |
assay at | Homo sapiens |
IC50 Value | IC50 Value Maximum | Comment | Organism | Inhibitor | Structure |
---|---|---|---|---|---|
1 | - |
pH 6.7, 37°C, recombinant enzyme | Homo sapiens | phosphate | |
5 | - |
pH 6.7, 37°C, recombinant enzyme | Homo sapiens | sulfate |
General Information | Comment | Organism |
---|---|---|
evolution | despite the low sequence identity between the unique N-sulfatase and the group of O-sulfatases, they share a similar overall fold and active-site architecture, including a catalytic formylglycine, a divalent metal-binding site and a sulfate-binding site. A highly conserved lysine in O-sulfatases is replaced in the N-sulfoglucosamine sulfohydrolase by an arginine (Arg282) that is positioned to bind the N-linked sulfate substrate | Homo sapiens |
malfunction | mucopolysaccharidoses are a group of recessively inherited lysosomal storage disorders caused by a deficiency of enzymes involved in the metabolic breakdown of glycosaminoglycans. Mucopolysaccharidosis type IIIA (Sanfilippo A syndrome), a fatal childhood-onset neurodegenerative disease with mild facial, visceral and skeletal abnormalities, is caused by an inherited deficiency of the enzyme N-sulfoglucosamine sulfohydrolase, more than 100 mutations in the SGSH gene are found to reduce or eliminate its enzymatic activity. The Sanfilippo syndrome signs of neurodegeneration are the initial symptoms and comprise of hyperactivity, developmental stagnation and psychomotor regression | Homo sapiens |
additional information | the enzyme shows low structural flexibility. The consensus active site lies in domain 1 in a narrow pocket at the bottom of a surface cleft and close to the end of the first beta-strand, active site structure, overview. Proposed interactions between the terminal N-sulfoglucosamine residue of the substrate with the enzyme in the active site | Homo sapiens |