Insights into Halophilic Protein Stability via the Generalized Born Model

Abstract

In contrast to proteins from bacteria that live in low salinity environments, proteins from halophiles, bacteria that live in inhospitable environments such as the Dead Sea, have been shown to be stabilized at high salt concentration and actually denature at ‘normal’ salinity. Furthermore, it is known that halophilic proteins have a higher number of negatively charged amino acids than non-halophilic proteins, particularly at their surfaces. Neither the reason for the halophilic proteins’ net surface charge nor its stabilization at high salinity is completely understood. In this study, randomly selected halophilic and non-halophilic proteins are investigated within the context of the Generalized Born model of implicit solvation. This analysis provides insight into how the charged nature of these halophilic proteins can increase their stability at high salinity while causing them denature at low salinity. Further insight is then gained via a detailed study of halophilic and non-halophilic protein homologues.