Determining the minimal amount of DMSO necessary to stabilize the Angiomotin lipid binding domain

Abstract

Angiomotins (Amots) are a family of adaptor proteins with important roles in cell growth, migration, and proliferation. The Amot coiled-coil homology (ACCH) domain has a high affinity for non-phosphorylated and mono-phosphorylated phosphatidylinositol which provides specificity in the membrane association. The membrane specificity is linked with targeting and recycling of the membrane protein to maintain normal cell phenotypes and function. Therefore, we endeavored to find the minimal amount of DMSO to stabilize the Amot lipid binding domain to eventually understand the protein function by studying its atomic structure. Our laboratory looked to determine the structure using nuclear magnetic resonance (NMR), which requires higher protein concentrations than those possible in our current buffered solutions. Based on literature reported on other proteins, DMSO can be used as a stabilizing agent up to 33-70%. Therefore, this work shows our preliminary findings for the minimal amount of dimethyl sulfoxide (DMSO) needed to stabilize the domain at higher concentrations without disrupting its native structure. To that end, we determined DMSO related changes in protein structure by analyzing shifts in the melting point determined by dynamic scanning fluorescence measurements. As a result, we found that the ACCH domain is denatured in solutions >10% DMSO.