Synthesis and Chemistry of Recombinant Gelsolin 1-3 as A Probe for The Ovarian Cancer Biomarker Lysophosphatidic Acid

Author(s): Navina Lotay, Cynthia Maria Suarez, Brian De La Franier, Rebecca Ann Jockusch and Michael Thompson

Gelsolin is an actin-binding protein that is competitively bound by lysophosphatidic acid (LPA), a possible biomarker for the early detection of ovarian cancer. Our group has previously shown the usage of gelsolin 1-3 (a fragment of gelsolin composed of the first three of its six subdomains) along with actin to detect the presence of lysophosphatidic acid. This histidine-tagged gelsolin 1-3 fragment is synthesized in our lab using bl21 Rosetta cells but required further characterization. This study aims to provide sufficient characterization of gelsolin 1-3 synthesized in our lab via both sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and mass spectrometry (MS) using a Fourier-transform ion cyclotron resonance mass spectrometer (FTICR-MS). These techniques show the presence of protein at the expected mass of approximately 41 kDa. Additionally, the dissociation of a smaller fragment of the complex when introduced into the gas phase which was equivalent to the approximate mass of one subdomain of gelsolin 1-3 further supports this conclusion.