Biophysical Society Conference | Tahoe 2023

Proton Reactions: From Basic Science to Biomedical Applications

Poster Abstracts

12-POS Board 12 DE NOVO DESIGN ELUCIDATES THE PHYSICOCHEMICAL DETERMINANTS OF PROTON TRANSPORT IN BIOLOGICAL SYSTEMS Gisselle Prida 2 ; Vincent T Silverman 1 ; Huong T Kratochvil 1 ; 1 University of North Carolina at Chapel Hill, Chemistry, Chapel Hill, NC, USA 2 University of North Carolina at Chapel Hill, Biochemistry and Biophysics, Chapel Hill, NC, USA In de novo protein design, we engineer proteins from first principles to isolate and critically investigate complex biophysical phenomena in simple, artificial model systems. In previous work, we defined the roles of water and hydrophobic domains in proton channels for the selective transport of protons across cell membranes. We engineered artificial proton channels by incorporating key polar proton loading sites in otherwise apolar stretches, allowing us to experimentally test the hypothesis of transient water wire formation in proton channel activity. Our work revealed how we can use de novo protein design to examine the roles of proton induced water wires in the selective transport of the proton. Now, we extend this work to investigate other physicochemical aspects of proton conduction in biological systems. Here, we design de novo proton channels with longer polar segments to explore the roles of pore solvation in proton conduction rates. In this work, we test how the length of the water wire that can form in the absence of a proton affects proton conductivity rates. Further, we explore how charged residues, like His, Asp, and Glu, affect aspects of channel assembly and function. Our combined approach of protein design, simulation, and biophysical experiment allows us to tackle key questions of the molecular and chemical basis for proton-selective transport in these complex natural systems.

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