Second Virial Coefficient Studies of Cosolvent-Induced Protein Self-Interaction

Abstract

Protein self-interaction is important in protein crystal growth, solubilization, and aggregation, both in vitro and in vivo, as with protein misfolding diseases, such as Alzheimer's. Although second virial coefficient studies can supply invaluable quantitative information, their emergence as a systematic approach to evaluating protein self-interaction has been slowed by the limitations of traditional measurement methods, such as static light scattering. Comparatively, self-interaction chromatography is an inexpensive, high-throughput method of evaluating the osmotic second virial coefficient (B) of proteins in solution. In this work, we used self-interaction chromatography to measure B of lysozyme in the presence of various cosolvents, including sucrose, trehalose, mannitol, glycine, arginine, and combinations of arginine and glutamic acid and arginine and sucrose in an effort to develop a better fundamental understanding of protein self-interaction in complex cosolvent systems. All of these cosolvents, alone or in combination, increased B, indicating a reduction in intermolecular attraction. However, the magnitude of cosolvent-induced changes in B was found to be largely dependent on the ability to control long-range electrostatic repulsion. To the best of our knowledge, this work represents the most comprehensive virial coefficient study to date focusing on complex cosolvent-induced effects on the self-interaction of lysozyme.

Applications of the second virial coefficient: protein crystallization and solubility

“…B-value experiments performed on approximately 70 different aqueous and membrane proteins clearly demonstrate the potential of the values as a diagnostic for initial crystallization conditions as well as for improving existing crystallization conditions (Berger et al, 2005(Berger et al, , 2006Dumetz et al, 2007;García, Hadley et al, 2003;Patro & Przybycien, 1996;Pjura et al, 2000;Tessier & Lenhoff, 2003;Tessier, Vandrey et al, 2002;Valente et al, 2005). However, in spite of the demonstrated capability of SLS B-value measurements to serve as a diagnostic for solution conditions that are more likely to result in crystals, this experimental approach has not gained traction within the crystallographic community.…”

“…The experiments shown here took approximately 20 min to generate a value for B, compared with Comparison of SIC (blue diamonds) and SLS data for lysozyme as a function of NaCl concentration. The data are taken from the following references: blue diamonds, Valente et al (2005); red squares, García, Holman et al (2003); green triangles, Guo et al (1999); purple circles, . several hours for each SLS data point.…”

Lysozyme‐lysozyme self‐interactions as assessed by the osmotic second virial coefficient: Impact for physical protein stabilization

“…Valente et al [13] have reported that sugars (e.g. sucrose) influence the conformational dynamics of proteins, favoring the most compact conformation within the native-state ensembles.…”

“…sucrose) influence the conformational dynamics of proteins, favoring the most compact conformation within the native-state ensembles. This reduction of protein volume is accompanied by a concomitant reduction in the hydrophobicity of the protein surface, thus reducing the tendency for protein-protein self association [13]. Kaushik and Bhat [98] have pointed out to another possible stabilization mechanism that has to be considered.…”

“…Different solution conditions have a strong impact on protein-protein interactions [10][11][12][13] and parameters that minimize proteinprotein interactions have to be identified in order to avoid the potential formation of protein aggregates [14][15][16].…”