Insights into protein stability in cell lysate by 19F NMR spectroscopy

Abstract

In living organisms, protein folding and function take place in an inhomogeneous, highly crowded environment possessing a concentration of diverse macromolecules of up to 400 g/L. It has been shown that the intracellular environment has a pronounced effect on the stability, dynamics and function of the protein under study and has for this reason to be considered. However, most protein studies are neglecting the presence of these macromolecules. Consequently, we probe here the overall thermodynamic stability of cold shock protein B from Bacillus subtilis ( Bs CspB) in cell lysate. We found that an increase in cell lysate concentration causes a monotonic increase in thermodynamic stability of Bs CspB. This result strongly underlines the importance of considering the biological environment when inherent protein parameters shall be quantitatively determined. Moreover, we demonstrate that the targeted application of 19 F NMR spectroscopy operates as an ideal tool utilized to protein studies performed in complex cellular surroundings.