Abstract
Proteins are believed to contain vital functional information of biosystems. In virus, structural proteins form the building blocks of the virus particle. Raman spectroscopy is a powerful technique to probe electronic structure at molecular vibration levels. However, due to weak Raman cross-section, there is no reliable conventional Raman spectroscopy on E-proteins in the virus. Herewith, a novel, non-destructive and direct technique, named correlated plasmon-enhanced Raman spectroscopy (CP-ERS) is developed to directly probe electronic and molecular vibrations of proteins. Intriguingly, using CP-ERS, new resonant quasielastic and inelastic electronic Raman scatterings and phonon excitations of E-proteins in dengue virus (DENV) are discovered. The CP-ERS is utilizing newly-developed highly oriented gold-quantum dots chips exhibiting low-loss tunable correlated-plasmons, high structural stability and reproducibility. By modifying E-protein, anomalous glycosylation-induced changes in CP-ERS are observed. Moreover, CP-ERS are used for training a machine learning algorithm, obtaining 100% accuracy in hold-out and 93% mean accuracy in grouped 5-fold cross-validation. Our result reveals new resonant quasielastic and inelastic Raman scatterings and new phonons of E-proteins in viruses and demonstrates a strategy in utilizing CP-ERS with machine learning to directly measure and quantify electronic structure and structural and molecular vibrations of biological and solid state systems.