Presenter(s): Lejla Biberic—Biochemistry
Faculty Mentor(s): Amber Rolland, James Prell
Session: Prerecorded Poster Presentation
Membrane proteins, including pore-forming toxins (PFTs), play important roles in human health . PFTs are promising for nanopore sequencing and drug delivery, but to maximize success in these applications, it is important to know the size of the pore and thus the oligomeric state (number of identical subunits) . The flexibility of alpha-PFT transmembrane helices may allow their oligomeric state to vary in different environments . Elucidating the relationship between oligomeric state and detergent environment is thus important for PFT bionanotechnology applications . Here, we studied how native oligomeric states of Cytolysin A (ClyA), an alpha-PFT found in pathogenic strains of Escherichia coli, varied in different detergent environments using native mass spectrometry (MS) . Native MS enables preservation of noncovalent complexes and accurate measurement of the complex mass . Together with a known monomer mass, this allows unambiguous determination of oligomeric state . ClyA was incubated with various detergents and screened for complex formation using Blue Native PAGE . Preliminary native MS results show that ClyA forms various oligomeric complexes ranging from octameric to dodecameric in n-dodecylÎ2-D-maltoside and octaethylene glycol monododecyl ether. ClyA forms no identifiable pore complexes in n-octyl-Î2-D-glucoside, in contrast to previous reports, while n-tetradecylphosphocholine heavily adducts to and stabilizes ClyA monomers only . Combining these experimental results with computational modeling enables further investigation into the relationship between detergent properties and oligomeric state . These findings will not only advance the fields of MS and structural biology but also provide new insight for PFT applications in bionanotechnology through manipulation of desired oligomeric state and pore size .