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Updated: May 11, 2026

A Microfluidic Approach for the Study of Ice and Clathrate Hydrate Crystallization
Published on: August 18, 2022
Effects of cryoprotectants on the structure and thermostability of the human carbonic anhydrase II-acetazolamide
Mayank Aggarwal1, Christopher D Boone, Bhargav Kondeti
1Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, 1600 SW Archer Road, PO Box 100245, Gainesville, FL 32610, USA.
Abstract:
Protein X-ray crystallography has seen a progressive shift from data collection at cool/room temperature (277-298 K) to data collection at cryotemperature (100 K) because of its ease of crystal preparation and the lessening of the detrimental effects of radiation-induced crystal damage, with 20-25%(v/v) glycerol (GOL) being the preferred choice of cryoprotectant. Here, a case study of the effects of cryoprotectants on the kinetics of carbonic anhydrase II (CA II) and its inhibition by the clinically used inhibitor acetazolamide (AZM) is presented. Comparative studies of crystal structure, kinetics, inhibition and thermostability were performed on CA II and its complex with AZM in the presence of either GOL or sucrose. These results suggest that even though the cryoprotectant GOL was previously shown to be directly bound in the active site and to interact with AZM, it affects neither the thermostability of CA II nor the binding of AZM in the crystal structure or in solution. However, addition of GOL does affect the kinetics of CA II, presumably as it displaces the water proton-transfer network in the active site.
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