Configurational entropy-based screening and selection of hydrophilic polymers using the tripartite split green fluorescent protein

Abstract

Measuring the entropic properties of polymers such as proteins is critical to accurate prediction of their functional properties. However, the measurement of configurational entropy is possible only by low throughput techniques such as calorimetry, NMR and CD spectroscopy. Moreover, to our knowledge no system exists that allows molecular selection/enrichment based on the molecules configurational entropy. We tested the ability of the scalable tripartite GFP system to offer fine resolution of differences in configurational entropy in molecules and to isolate molecules based on their configurational entropy. The system was able to both finely resolve molecules with different configurational entropies, as well as capture them for isolation. We were able to tune the sensitivity of the system by using different mutations of the protein components. Lastly, we were able to apply the system to polypeptoid molecules and posit that the system may be applied to any other hydrophilic polymer of up to 10^3 repeating units.