The fast intrinsic time scale of vibrational spectroscopy techniques means that biomolecular structural fluctuations across many time and length scales can be directly revealed using variations in the frequencies of site-specific normal modes at key positions. While many functional groups contain solvatochromic normal modes that can report unique information relevant to atom-level biomolecular structures and dynamics, the physical factors that determine vibrational probes’ frequency dependence can be complicated and convoluted in observed spectral frequencies and lineshapes. For some probes (especially nitriles) in biomolecular environments, the frequency of a specific normal mode can be “highly degenerate”, meaning that multiple structures or structural environments around that probe site could lead to similar or identical frequencies, thus complicating interpretability of experimental spectroscopic data. Several considerations and challenges in the use of vibrational probe data will be discussed, including solvatochomic physical factors of different length scales, structural and dynamic perturbations due to the presence of artificial functional groups, signal strength limitations, and incorporation techniques. A general approach to using vibrational probe data to refine and validate protein structural ensembles will be proposed, and paths forward towards using solvatochromic Raman spectral data across longer length and time scales will be introduced.

Solvatochromic vibrational probes in biomolecules: What are they food for (and not)?

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.