Biomolecules possess an extraordinary level of functional specificity and efficiency, making it advantageous to immobilize them onto inorganic substrates and exploit their properties for applications in sensing or catalysis. Successful immobilization of biomolecules requires the preservation of conformation when bound at surfaces that deviate drastically from their native cellular environment. Moreover, the stability of a biomolecule’s structure depends on the distinct presence or absence of water molecules in and around their domains. Despite this, conventional methods for characterizing biomolecules at inorganic surfaces do not give direct information about water molecules associated with the surface, or how biomolecules conform upon transitioning from ambient environments to aqueous solutions. Our laboratory uses neutron reflectometry to elucidate the location of molecularly bound water within peptides and proteins functionalized onto gold surfaces. Additionally, we are measuring how these structures change when immersed in water. To accomplish this, we have developed a strategy for protein functionalization of surfaces that preserves native protein structure by covalently tethering short, helical peptides to a self-assembled monolayer on a gold substrate. Our helical peptides are designed to have solution-facing surfaces that electrostatically attract and immobilize proteins of interest to the surface. Our peptide functionalized surfaces were analyzed with the Liquids Reflectometer at Oak Ridge National Laboratory under contrasting environments to determine water’s role in stabilizing the structures of the helical peptide. This information, and future reflectometry analysis of immobilized proteins, will fill a vital gap in understanding that stands in the way of developing a truly comprehensive knowledge of how biomolecules behave at bio/abio interfaces.

Understanding water interactions at the biomolecule/surface interface through neutron reflectometry

253rd National Meeting (2017)

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