Data-Driven Discovery of the Origins of UV Absorption in Alpha-3C Protein

Fuente: arXiv
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Autores principales: Hozana, Germaine Neza, Mirón, Gonzalo Díaz, Hassanali, Ali
Formato: Preprint
Publicado: 2024
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author Hozana, Germaine Neza
Mirón, Gonzalo Díaz
Hassanali, Ali
author_facet Hozana, Germaine Neza
Mirón, Gonzalo Díaz
Hassanali, Ali
contents Over the last decade, there has been a growing body of experimental work showing that proteins devoid of aromatic and conjugated groups can absorb light in the near-UV beyond 300 nm and emit visible light. Understanding the origins of this phenomena offers the possibility of designing non-invasive spectroscopic probes for local interactions in biological systems. It was recently found that the synthetic protein α3C displays UV-vis absorption between 250-800 nm which was shown to arise from charge-transfer excitations between charged amino acids. In this work, we use data-driven discovery to revisit the origins of these features using molecular dynamics and excited-state simulations. Specifically, an unsupervised learning approach beginning with encoding protein environments with local atomic descriptors, is employed to automatically detect relevant structural motifs. We identify three main motifs corresponding to different hydrogen-bonding patterns that are subsequently used to perform QM/MM simulations including the entire protein and solvent bath with the density-functional tight-binding (DFTB) approach. Hydrogen-bonding structures involving arginine and carboxylate groups appear to be the most prone to near-UV absorption. We show that these features are highly sensitive to the size of the QM region employed as well as to the inclusion of explicit solvation underscoring the limitations of using gas-phase cluster models.
format Preprint
id arxiv_https___arxiv_org_abs_2410_08624
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Data-Driven Discovery of the Origins of UV Absorption in Alpha-3C Protein
Hozana, Germaine Neza
Mirón, Gonzalo Díaz
Hassanali, Ali
Chemical Physics
Over the last decade, there has been a growing body of experimental work showing that proteins devoid of aromatic and conjugated groups can absorb light in the near-UV beyond 300 nm and emit visible light. Understanding the origins of this phenomena offers the possibility of designing non-invasive spectroscopic probes for local interactions in biological systems. It was recently found that the synthetic protein α3C displays UV-vis absorption between 250-800 nm which was shown to arise from charge-transfer excitations between charged amino acids. In this work, we use data-driven discovery to revisit the origins of these features using molecular dynamics and excited-state simulations. Specifically, an unsupervised learning approach beginning with encoding protein environments with local atomic descriptors, is employed to automatically detect relevant structural motifs. We identify three main motifs corresponding to different hydrogen-bonding patterns that are subsequently used to perform QM/MM simulations including the entire protein and solvent bath with the density-functional tight-binding (DFTB) approach. Hydrogen-bonding structures involving arginine and carboxylate groups appear to be the most prone to near-UV absorption. We show that these features are highly sensitive to the size of the QM region employed as well as to the inclusion of explicit solvation underscoring the limitations of using gas-phase cluster models.
title Data-Driven Discovery of the Origins of UV Absorption in Alpha-3C Protein
topic Chemical Physics
url https://arxiv.org/abs/2410.08624