Probing the conformational dynamics of an OTU deubiquitinase enzyme active site

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Date
2016
Authors
Hutchings, Roy
Hutchings, Roy
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Abstract
Enzymes are fundamental to cell function. Despite this, exactly how they work remains unclear. Enzymes exist as 3D folded structures determined by their amino acid sequence, and these structures are necessary for function. However, enzymes change their 3D conformation frequently during the course of a reaction, and an understanding of these dynamic motions is necessary for a complete understanding of enzyme function. As a model for enzyme dynamics, we have studied the catalytic domain of Otu1, an ovarian tumour domain-containing deubiquitinase from yeast Saccharomyces cerevisiae. Deubiquitinases catalyze the breakdown of ubiquitin, and play an important role in regulating cell functions including immune response and signal transduction. We have probed the structural dynamics of the catalytic domain of Otu1 using the cysteine-labelling molecule 4,4’-dithiodipyridine (DTDP). The labelling reaction kinetics have been followed using stopped-flow fluorescence spectroscopy methods and have revealed the presence of a conformational change with a frequency of 127 ± 7 s-1. This conformational change may potentially play a role in the enzyme’s catalytic mechanism.
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Biochemistry, Enzyme dynamics
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