Book of Abstracts: Albany 2007
June 19-23 2007
Surface Side Chains Dynamics in Protein Thermostability
Mechanism of thermostabilization of proteins structure is not yet known and still object of high interest. We showed that regulatory mechanism of thermostabilization has entropic nature, determined by dynamic properties of charged and polar side chains on the protein surface. These dynamic properties are crucial for formation of effective alternative hydrogen bonds (1). Apparently, thermostabilization strategy is to provide the required stability to the native structure not by formation of maximally possible amount of hydrogen bonds, but by using an optimal amount of alternative hydrogen bonds situated in the crucial place of protein structure.
In the context of development of model of alternative hydrogen bonding of side chains on the protein surface in this work an results of MD simulations of DNA binding protein SSO7D from Sulfoglobus solfataricus (1SSO) and his mutant form F31A (1B4O) at different temperatures in aqueous solution are presented. We analyzed conformations of charged and polar side chains of both proteins and their role in protein thermostability.
Figure illustrates mechanism of alternative H-bonding on the example of charged side chains of A1; K4, K6; R24; E11, E47; D15, D49, and S46 of SSO7D structure that are responsible for thermostability. From the Figure, one can see that, for example, Lysine K6 has three alternative H-bonding partners E11, S46, and D49; Lysine k4 has two partners -- E11 and D49.
References and Footnotes
A. V. Kabanov*
Institue of Cell Biophysics