Recently, there has been significant interest in intrinsically disordered proteins (IDPs) because they challenge the postulate that the structure of a protein dictates its function. Bacterial anti-σ factor FlgM is one such IDP, which exists in thermophile A. aeolicus and maintains its function despite being both in a high temperature environment (358K optimum growth temperature) and intrinsically disordered. FlgM binds to σ28 in a regulatory step of the bacterial flagellar biosynthesis pathway. This study uses molecular dynamics simulations and computational analysis to assess the evolution of secondary structure over time, root mean square fluctuation of the protein backbone, and other measures of FlgM structure at both 300K and 358K. Parallel simulations were performed with FlgM in complex with σ28 to further assess IDP behavior and FlgM stability. Additionally, in order to control the fleeting ordered conformation of FlgM, we varied concentrations of the room temperature ionic liquid (RTIL) 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C4mpy][Tf2N]) in the FlgM and FlgM- σ28 complex simulations. The increased ionic strength and viscosity of RTIL in the solvation shell will stabilize either the ordered or disordered state of FlgM. The analysis is specifically focused on the thermal and ionic environmental factors that influence the stability of FlgM. The RTIL-FlgM simulations will also provide important information regarding the utility of RTILs in protein and IDP systems in the future.

Influence of environment and temperature on the structure of the thermophilic intrinsically disordered protein FlgM

251st National Meeting (2016)

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