Collaborative Research: Optimizing Photosynthesis: Understanding how membrane lipids tune light collection by LHCII for excitation transfer at the quantum level.

About This Grant

The research will provide new insights into how lipids in the plant thylakoid membranes, the site of photosynthesis, control and fine-tune harvesting of sunlight by highly specialized light-harvesting complex II proteins (LHCII) through quantum photochemistry. The work will identify the optimal lipid membrane composition for light harvesting, balancing the competing demands of photoprotection vs. photo-efficiency. This information is crucial for optimizing photosynthetic energy conversion in crops to meet the challenges of the 21st century. Educational activities that include student training and public outreach to encourage young children to explore how science and engineering can help improve our world will contribute to the development of a STEM workforce and general scientific literacy. The precise influence of the physical properties of membrane lipid bilayers, such as lipid chain length and the volume they occupy, on the structure and function of LHCII and other photosynthetic proteins is unknown. This research aims to utilize a recently developed LHCII proteoliposome pipeline, combined with single-molecule spectroscopy and molecular dynamics simulations, to elucidate the role of physical lipid properties in the fine-tuning of light harvesting by individual LHCII proteins. Proteoliposomes are small spherical vesicles comprising a lipid bilayer with incorporated membrane proteins such as LHCII. The experiments aim to validate our hypothesis that a specific lipid length and morphology (volume) optimize sunlight collection by LHCII, enabling efficient photochemistry by tuning protein structure to optimize excitation transfer at the quantum level. To achieve this, a distinctive real-time, feedback-driven single-particle tracking system will be employed for the comprehensive characterization of lipid-protein interactions at the level of individual LHCII molecules within well-defined proteoliposomes. These experimental results will be simulated through molecular dynamics simulations, offering profound mechanistic insights into how the physical properties of lipids influence the structural and functional attributes of LHCII. The integrated methodology constitutes an innovative research platform that facilitates the systematic analysis of lipid-protein interactions with sub-molecular resolution on individual LHCII proteins, adaptable to other systems. The anticipated outcomes are expected to enhance our broader understanding of physicochemical dynamics within membranes and their role in the sunlight-harvesting process in plants. This contribution is of considerable significance, providing unprecedented mechanistic insight into how lipids govern the functionality of a crucial photosynthetic membrane protein. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.