Poster abstracts
Poster number 126 submitted by Shubhangi Sharma
Integrating Bioinformatics and Molecular Dynamics to Reveal Cross-Species Differences in Non-Photochemical Quenching Mechanisms
Shubhangi Sharma (Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio), Amr Dodin (Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio)
Abstract:
Photosynthesis is fundamental to life, with light-harvesting complexes (LHCs) serving as key molecular systems that absorb light and regulate its transfer and dissipation under varying light intensities. LHCII proteins balance efficient light harvesting with photoprotection through non-photochemical quenching (NPQ), yet the molecular determinants underlying the process remain poorly understood. A key question is how sequence and structural elements in these proteins regulate energy transfer and dissipation across different photosynthetic organisms. Despite extensive sequence data, linking conserved patterns to structural and functional mechanisms remains challenging. LHC proteins exhibit highly conserved chlorophyll a/b-binding domains but subtle conformational changes, especially near pigment interaction sites such as chlorophyll and carotenoid binding regions, can significantly alter photophysical behavior. Understanding how these conserved residues contribute to pigment interactions and NPQ regulation is further complicated by species-specific variations and the dynamic nature of these proteins.
In this work, we integrate bioinformatics, structural analysis, and molecular dynamics (MD) simulations to investigate the relationship between sequence conservation, structure, and dynamics in LHC proteins across 65 photosynthetic species. We analyze representative LHC proteins to quantify the proximity of conserved residues to bound pigments and identify evolutionary constraints on functionally critical regions. We then use MD simulations to characterize how these proteins transition between different states and to compare the associated thermodynamics and kinetics across species. By combining sequence-based insights with structural and dynamic analysis, this study aims to bridge the gap between abundant sequence data and a limited understanding of protein dynamics. This integrated framework enables a comparative view of how similar proteins achieve different functional outcomes across species, providing insight into how NPQ mechanisms are tuned to diverse environmental conditions. More broadly, this approach offers a foundation for linking sequence, structure, and dynamics to function in photosynthetic systems.
Keywords: photosynthesis, protein, LHC