Examination of the mechanism of human brain aspartoacylase through the binding of an intermediate analogue.

Abstract

Canavan disease is a fatal neurological disorder caused by the malfunctioning of a single metabolic enzyme, aspartoacylase, that catalyzes the deacetylation of N-acetyl-L-aspartate to produce L-aspartate and acetate. The structure of human brain aspartoacylase has been determined in complex with a stable tetrahedral intermediate analogue, N-phosphonomethyl-L-aspartate. This potent inhibitor forms multiple interactions between each of its heteroatoms and the substrate binding groups arrayed within the active site. The binding of the catalytic intermediate analogue induces the conformational ordering of several substrate binding groups, thereby setting up the active site for catalysis. The highly ordered binding of this inhibitor has allowed assignments to be made for substrate binding groups and provides strong support for a carboxypeptidase-type mechanism for the hydrolysis of the amide bond of the substrate, N-acetyl- l-aspartate.

• Authors: Johanne Le Coq, Alexander Pavlovsky, Radhika Malik, Ruslan Sanishvili, Chengfu Xu, Ronald E Viola
• Journal: Biochemistry (Biochemistry) Vol. 47 Issue 11 Pg. 3484-92 (Mar 18 2008) ISSN: 0006-2960 [Print] United States
• PMID: 18293939 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, U.S. Gov't, Non-P.H.S.)

Chemical References

• Apoenzymes
• Enzyme Inhibitors
• N-phosphonomethylaspartic acid
• Organophosphorus Compounds
• Aspartic Acid
• Carboxypeptidases
• Amidohydrolases
• aspartoacylase

Topics

• Amidohydrolases (antagonists & inhibitors, chemistry, genetics, metabolism)
• Apoenzymes (antagonists & inhibitors, chemistry, genetics, metabolism)
• Aspartic Acid (analogs & derivatives, chemistry, metabolism)
• Binding Sites (genetics)
• Brain (enzymology)
• Carboxypeptidases (chemistry, metabolism)
• Catalysis
• Crystallography, X-Ray
• Enzyme Inhibitors (metabolism)
• Glycosylation
• Humans
• Mutagenesis, Site-Directed
• Organophosphorus Compounds (chemistry, metabolism)
• Protein Binding (genetics)