Surface immobilization of peptides and proteins has become an important topic in many applications in analytical, clinical, environmental, and industrial chemistry. During these applications, harsh treatments are often applied such as dry state, extreme temperature, pH, or organic solvents, which are referred to as abiotic. Hydroxyl-rich molecules including carbohydrates, glycerol, and polyethylene glycol have shown to preserve peptide/protein structures in certain abiotic environments. However, researchers have not been able to show in situ molecular level evidence on the preservation due to the lack of appropriate tools. In this work, a selected sugar molecule was used to demonstrate the ability to replace water to retain the structure of surface immobilized enzyme in an abiotic environment. Using an intrinsically surface sensitive technique, sum frequency generation vibrational spectroscopy (SFG), the conformation and orientation of sugar-protected enzymes were measured and calculated in dry condition as well as at different humidity levels. Results were compared to similar measurements for non-protected enzymes. The enzymatic activity was also tested and correlated in both cases. In a parallel work, it has also been found that some hydrophobicity is required to retain the structure of membrane-reactive a-helical antimicrobial peptides (AMPs). We have been attempted to comment on the mechanisms of the preservation of surface-immobilized peptide and protein structures using the unique vibrational spectroscopy technique and rationalize the design rules for �water-free biologics� based on our engineered abiotic/biotic interfaces.

Molecular-level evidence on preservation of immobilized peptide and protein structures in abiotic environment

246th National Meeting (2013)

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