Kaare Bjerregaard-Andersen

P8 Isatin hydrolase: Diagnostics tool at atomic resolution (selected for oral presentation)

Kaare Bjerregaard-Andersen et al.

p8 Isatin hydrolase: Diagnostics tool at atomic resolution

Isatin is a small aromatic compound found in a range of biological systems, e.g. in mammals as mono amine oxidase (MAO)
inhibitor and in plants as a hormone. In mammals it has also been identified as a potential biomarker in Parkinsons disease1. We used isatin hydrolase, isolated from Labrenzia aggregata from in the Baltic sea, in a detection and quantification as- say for isatin in biological samples. In this study we determined the crystal structure of isatin hydrolase to 1.4A resolution to understand the mechanism of enzyme reactivity. We also char- acterized the enzyme kinetics and thermody- namics. Isatin hydrolase is stable to 65 oC and binds manganese(II) with KD = 10 μM – app. 12 fold stronger than other common divalent metal 
ions. The enzyme structure revealed a dimeric enzyme with two domain swaps. A substrate recognition site and water entry channel to active site has also been identified. An inhib- itor was identified and co-crystallized with the enzyme. Using the crystal structure isatin hydrolase can provide a scaffold for rational protein engineering toward new specificities. Schiff-bases of isatins forms a group of mole- cules with high pharmacological potential as e.g. cancer drugs.
1  Res Commun Mol Pathol Pharmacol. 2000  Jul-Aug;108(1-2):63-73.