Ionic-Liquid-Functionalized Mineral Particles for Protein Crystallization

Kowacz, M, Marchel M, Juknaite L, Esperanca J, Romao MJ, Carvalho AL, Rebelo LPN.  2015.  Ionic-Liquid-Functionalized Mineral Particles for Protein Crystallization. Crystal Growth & Design. 15:2994-3003., Number 6


Nucleation is a critical step determining the outcome of the entire crystallization process. Finding an effective nucleant for protein crystallization is of utmost importance for structural biology. The latter relies on good-quality crystals to solve the three-dimensional structures of macromolecules. In this study we show that crystalline barium sulfate (BaSO4) with an etched and/or ionic liquid (IL)-functionalized surface (1) can induce protein nucleation at concentrations well below the concentration needed to promote crystal growth under control conditions, (2) can shorten the nucleation time, (3) can increase the growth rate, and finally (4) may help to improve the protein crystal morphology. These effects were shown for lysozyme, RNase A, trypsin, proteinase K, myoglobin, and hemoglobin. Therefore, the use of BaSO4 particles enables us to reduce the amount of protein in crystallization trials and increases the chance of obtaining protein crystals of the desired quality. In the context of the underlying mechanism, it is shown that the protein-solid contact formation is governed by the interaction of the polar compartments of the biomacromolecule with the support. The tendency of a protein to concentrate near the solid surface is enhanced by both the hydrophobicity of the protein and that of the surface (tuned by the functionalizing IL). These mechanisms of interaction of biomacromolecules with inorganic hydrophilic solids correspond to the principles of amphiphilic IL-mineral interactions.


ISI Document Delivery No.: CK0JB Times Cited: 0 Cited Reference Count: 42 Kowacz, M. Marchel, M. Juknaite, L. Esperanca, J. M. S. S. Romao, M. J. Carvalho, A. L. Rebelo, L. P. N. Esperanca, Jose/B-5116-2008; Esperanca, Jose/0000-0001-9615-8678; Marchel, Mateusz/0000-0002-2274-1139; Juknaite, Lina/0000-0002-5739-7788 Fundacao para a Ciencia e a Tecnologia (FCT), Portugal [PTDC/BBB-BEP/3058/2012, PEst-OE/EQB/LA0004/2013, UID/Multi/04378/2013, PEst-C/EQB/LA0006/2013, RECI/BBB-BEP/0124/2012, SFRH/BPD/63554/2009]; Investigator FCT Program; COMPETE Program The authors thank Dr. Teresa Santos-Silva and Ph.D. student Hugo Correia for kindly providing the crystallization conditions for bovine blood hemoglobin and pancreatic trypsin. The authors acknowledge financial support from Fundacao para a Ciencia e a Tecnologia (FCT), Portugal, through R&D Projects PTDC/BBB-BEP/3058/2012, PEst-OE/EQB/LA0004/2013 (to ITQB), UID/Multi/04378/2013, PEst-C/EQB/LA0006/2013 (to Associate Lab UCIBIO-REQUIMTE), and RECI/BBB-BEP/0124/2012 and also through a postdoctoral grant (SFRH/BPD/63554/2009) and a contract under the Investigator FCT 2012 Program and the COMPETE Program. The authors also thank the ESRF (Grenoble, France) and the Diamond Light Source (Didcot, U.K.) for access to data collection facilities. 9 Amer chemical soc Washington 1528-7505

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