Investigating the Structure and Topology of the Pinholin Membrane Protein Using Pulsed Deer and CW-EPR Spectroscopic Techniques

Abstract

surfaces. Through molecular dynamics simulations, we have identified fourteen basic residues on the human Slp-4 C2A domain that contribute directly to membrane binding. These include a cluster of three lysines that are known to comprise the central PIP2-binding site conserved among PIP2-binding C2 domains, while the remaining eleven are spread over a large electropositive surface. We hypothesize that this surface provides a nonspecific electrostatic anchor to PS and that therefore that the net charge on the surface is likely to be more strongly evolutionarily conserved than the individual residues. To test this hypothesis, we are using primary sequence alignments to assess the level of conservation at individual residues, along with electrostatic calculations coupled with high-throughput structure prediction to compare the electropositive surface among Slp C2 domains from a wide range of animals. Current results from this ongoing study will be shown. This approach may be of broad interest for characterizing nonspecific yet potentially strong electrostatic interactions between proteins and charged surfaces.