Conformational plasticity enables functional switching in diatom light-harvesting complexes

Area of Science:

• Biophysics
• Photosynthesis research
• Marine biology

Background:

• The structure-function relationship in biomolecules, particularly proteins, is crucial for their biological activity.
• Understanding environmental modulation of protein structure and function is a key challenge in molecular biology.
• Light-harvesting complexes (LHCs) in diatoms are vital for photosynthesis in marine environments.

Purpose of the Study:

• To investigate the correlation between structure and function in diatom light-harvesting complexes (LHCs).
• To explore the conformational dynamics of LHCs and their impact on light-harvesting and photoprotective processes.
• To provide a novel perspective on the various experimentally resolved LHC structures.

Main Methods:

• Utilizing microsecond-long molecular dynamics simulations.
• Applying machine learning techniques to analyze simulation data.
• Correlating computational findings with experimental data on LHCX1 and the xanthophyll cycle.

Main Results:

• Identified a few distinct, interconverting conformational states for diatom LHCs.
• Revealed an intrinsic conformational transition influencing the balance between light-harvesting and photoprotection.
• Demonstrated that these states correlate with experimental observations of acclimation.

Conclusions:

• Experimentally resolved LHC structures represent a limited set of interconverting states.
• The conformational dynamics of LHCs are tunable and potentially engineerable.
• The findings offer insights into diatom acclimation mechanisms involving LHCX1 and the xanthophyll cycle.