Biophysical Society Conference | Tahoe 2024

Molecular Biophysics of Membranes

Poster Abstracts

10-POS Board 13 IDENTIFYING THE EFFECTS OF PROTON CHANNEL HYDRATION ON SELECTIVE CONDUCTION ACROSS A MEMBRANE Nolan P. Jacob ; Vincent Silverman 1 ; Gisselle Prida 2 ; Huong Kratochvil 1 ; 1 The University of North Carolina at Chapel Hill, Chemistry, Chapel Hill, NC, USA 2 The University of North Carolina at Chapel Hill, BCBP, Chapel Hill, NC, USA Membrane channels are important for performing basic biological mechanisms such as regulating intracellular pH and creating ion gradients, both of which are necessary for proper cellular function and signaling. However, the size, complexity, and stability of these channels make them difficult to study in vitro. De novo protein design allows us to distill these proteins into simple model systems which we can use to test basic mechanisms of channel and transporter function. Specifically, previous research determined the role of water wires in the transport of protons within a designed pentameric scaffold channel by replacing nonpolar pore-facing residues with polar side chains to introduce water into the channel and achieve selective proton conduction across the membrane. My project sought to extend water wire formation throughout the channel by adding additional polar residues to address questions of pore hydration’s effect on proton conductivity. We used computational molecular dynamics simulations, X-ray crystallography, and functional assays to define the roles of water wires in proton movement. From these experiments, we show that the relative placement of polar residues in the pore not only affects their channel assembly, but also alters their ability to explore different rotameric states, which ultimately impacts water accessibility into the pore.

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