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Protein crystallization in ionic-liquid hydrogel composite membranes

DOI: 10.3390/cryst9050253 DOI Help

Authors: Benny Danilo Belviso (Institute of Crystallography, CNR) , Rosanna Caliandro (Free University of Bozen) , Shabnam Majidi Salehi (Institute on Membrane Technology, CNR) , Gianluca Di Profio (Institute on Membrane Technology, CNR) , Rocco Caliandro (Institute of Crystallography, CNR)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Crystals , VOL 9

State: Published (Approved)
Published: May 2019
Diamond Proposal Number(s): 15832

Open Access Open Access

Abstract: Protein crystallization is a powerful purification tool. It is the first step for crystallographic structural investigations, and can be preparatory for biotechnological applications. However, crystallizing proteins is challenging and methods to control the crystallization process are needed. Ionic-liquid hydrogel composite membranes (IL-HCMs) have been used here as material capable of supporting protein crystallization and hosting grown crystals. We found that IL-HCMs affect the selection mechanism of glucose isomerase (GI) polymorphs and make GI crystals grow completely immersed into the hydrogel layer. X-ray diffraction studies show that IL ions do not bind to the protein, likely because IL molecules are constrained in the polymeric framework. Our GI crystal structures have been compared with many existing GI crystal structures using multivariate analysis tools, allowing a comprehensive overview of factors determining structural similarities, i.e., temperature variations and external stresses exerted during or after crystal growth, such as dehydration or presence of hydrogel of a different nature. GI crystals grown on IL-HCM fit perfectly in this framework, showing typical features induced by external forces. Overall, protein crystallization by IL-HCMs show potential for biotechnological applications, as it could constitute a natural means for containing crystallized enzymes in working conditions.

Journal Keywords: ionic liquids; hydrogel composite membranes; protein crystallization; glucose isomerase; structural model comparison

Subject Areas: Biology and Bio-materials

Instruments: I04-Macromolecular Crystallography