Has anybody successfully used the following method?
A simple method for improving protein solubility and long-term stability.
Golovanov AP, Hautbergue GM, Wilson SA, Lian LY.
Department of Biomolecular Sciences, University of Manchester Institute of Science and Technology, P. O. Box 88, Manchester M60 1QD, UK.
a.golovanov@umist.ac.jp
J Am Chem Soc. 2004 Jul 28;126(29):8933-9.
Abstract:
Increasing a protein concentration in solution to the required level, without causing aggregation and precipitation is often a challenging but important task, especially in the field of structural biology; as little as 20% of nonmembrane proteins have been found to be suitable candidates for structural studies predominantly due to poor protein solubility. We demonstrate here that simultaneous addition of charged amino acids L-Arg and L-Glu at 50 mM to the buffer can dramatically increase the maximum achievable concentration of soluble protein (up to 8.7 times). These amino acids are effective in preventing protein aggregation and precipitation, and they dramatically increase the long-term stability of the sample; additionally, they protect protein samples from proteolytic degradation. Specific protein-protein and protein-RNA interactions are not adversely affected by the presence of these amino acids. These additives are particularly suitable for situations where high protein concentration and long-term stability are required, including solution-state studies of isotopically labeled proteins by NMR.