Interaction of arylsulfatase-A (ASA) with its natural sulfoglycolipid substrates: a computational and site-directed mutagenesis study.
Glycoconj J
; 26(8): 1029-45, 2009 Nov.
Article
em En
| MEDLINE
| ID: mdl-19381802
ABSTRACT
Arylsulfatase A (ASA) hydrolyzes sulfate esters with a pH optimum of 5. Interactions between p-nitrocatechol sulfate (NCS, artificial substrate) and active site residues of ASA are revealed from their co-crystal structure. Since equivalent ASA interactions with its natural substrates, sulfogalactosylceramide (SGC) and sulfogalactosylglycerolipid (SGG), are not known, we computationally docked SGC/SGG to the ASA crystal structure. Our dockings suggested that Cys69 was the active site residue, and Lys302 & Lys123 as residues anchoring the sulfate group of SGC/SGG to the active site, as observed for NCS. We further confirmed these results using 2 recombinant ASA mutants C69A and CKK (Cys69, Lys302 and Lys123-all mutated to Ala). Both ASA mutants failed to desulfate SGC/SGG, and CKK showed minimal binding to [(14)C]SGC, although C69A still had affinity for this sulfoglycolipid. However, our dockings suggested additional intermolecular hydrogen bonding and hydrophobic interactions between ASA and SGC/SGG, thus contributing to the specificity of SGC/SGG as natural substrates.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Glicolipídeos
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Cerebrosídeo Sulfatase
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Mutagênese Sítio-Dirigida
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Biologia Computacional
Limite:
Animals
Idioma:
En
Revista:
Glycoconj J
Assunto da revista:
BIOQUIMICA
/
METABOLISMO
Ano de publicação:
2009
Tipo de documento:
Article
País de afiliação:
Canadá