Microsolvation of Protonated Glycine: Infrared Spectra from Data-Driven Quantum Many-Body Simulations

Accurate molecular models are a critical aspect of computational biochemistry, enabling reliable predictions of the behavior and chemical properties of complex biological systems. Glycine, the simplest amino acid, serves as a key building block of proteins and peptides, making it an ideal model for studying biomolecular interactions. Additionally, protonated glycine-water interactions are extremely important in many biological processes, and understanding their microhydration structure and dynamics requires accurate computational approaches. As part of an effort to model generic biomolecular systems, we developed a data-driven many-body energy (MB-nrg) potential energy function (PEF) to serve as a predictive molecular model and combined it with path-integral based quantum dynamics methods to investigate microsolvation structure and dynamics. Analyses of structural properties and vibrational spectra of protonated glycine in gas-phase water clusters in comparison to experiment indicate that our MB-nrg PEF provide a realistic description of the hydration structure, enabling a detailed characterization of the hydration process, one water molecule at a time.