Biomolecular Binding at Aqueous Interfaces of Langmuir Monolayers of Bioconjugated Amphiphilic Mesogenic Molecules: A Molecular Dynamics Study

We
report a molecular dynamics (MD) simulation study of protein
binding at the aqueous–liquid crystal (LC) interfaces of bioconjugated
mesogenic molecules. As a simple model of these interfaces, we use
monolayers composed of biotin-conjugated or biotin-free amphiphilic
mesogenic molecules and streptavidin in water. The all-atom MD simulations
reveal that the binding of streptavidin to the biotin mesogenic monolayer
is significantly stronger than that to biotin-free mesogenic monolayers.
Although specific protein binding marginally increases the overall
orientational order and the tilt of the biotin-conjugated mesogenic
molecules of the monolayer, significant changes in tilt were observed
near the bound protein (in contrast to the protein interaction with
the monolayer without biotin). We also observe that specific protein
binding changes the dynamic properties of the mesogens within the
monolayer (e.g., lateral diffusion coefficients) and associated water.
Overall, these MD simulations advance our understanding of the molecular-level
phenomena involved in the binding of biomolecules and subsequent dynamic
changes at the aqueous–LC interfaces. These results provide
guidance to future molecular-level designs of biofunctional LC interfaces.