Phase diagram for a model of urate oxidase.
Urate oxidase from Asperigillus flavus has been shown to be a model protein for studying the effects of polyethylene glycol (PEG) on the crystallization of large proteins. Extensive experimental studies based on small angle x-ray scattering [Vivares and Bonnete, J. Phys. Chem. B 108, 6498 (2004)] have determined the effects of salt, pH, temperature, and most importantly PEG on the crystallization of this protein. Recently, some aspects of the phase diagram have also been determined experimentally. In this paper, we use Monte Carlo techniques to predict the phase diagram for urate oxidase in solution with PEG, including the liquid-liquid and liquid-solid coexistence curves. The model used includes an electrostatic interaction, van der Waals attraction, and a polymer-induced depletion interaction [Vivares et al., Eur. Phys. J. E 9, 15 (2002)]. Results from the simulation are compared with experimental results.
Wentzel
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Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015, USA. njw4@lehigh.edu
Pagan
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Gunton
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JD
D001231:Aspergillus flavus / Q000201:enzymology*; D003198:Computer Simulation; D005656:Fungal Proteins / Q000737:chemistry*; D008956:Models, Chemical; D009010:Monte Carlo Method; D044367:Phase Transition; D011092:Polyethylene Glycols / Q000737:chemistry; D014503:Urate Oxidase / Q000737:chemistry*
D005656:Fungal Proteins; D011092:Polyethylene Glycols; D014503:Urate Oxidase