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Updated: Aug 13, 2026

The Importance of Correct Protein Concentration for Kinetics and Affinity Determination in Structure-function Analysis
Published on: March 17, 2010
Catalysis of serine oligopeptidases is controlled by a gating filter mechanism
V Fülöp1, Z Szeltner, L Polgár
1Department of Biological Sciences, University of Warwick, Coventry, UK.
Abstract:
Proteases have a variety of strategies for selecting substrates in order to prevent uncontrolled protein degradation. A recent crystal structure determination of prolyl oligopeptidase has suggested a way for substrate selection involving an unclosed seven-bladed beta-propeller domain. We have engineered a disulfide bond between the first and seventh blades of the propeller, which resulted in the loss of enzymatic activity. These results provided direct evidence for a novel strategy of regulation in which oscillating propeller blades act as a gating filter during catalysis, letting small peptide substrates into the active site while excluding large proteins to prevent accidental proteolysis.
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