Long-lived quantum coherence in photosynthetic complexes at physiological temperature

Area of Science:

• Photosynthesis research
• Quantum biology
• Biophysics

Background:

• Photosynthetic antenna complexes efficiently capture solar energy via excitation transfer.
• Coherent energy transfer, a quantum mechanical process, has been observed at cryogenic temperatures.
• Theoretical models predict environmentally assisted quantum transfer efficiency at physiological temperatures, requiring long-lived coherence.

Purpose of the Study:

• To investigate the survival of quantum coherence in the Fenna-Matthews-Olson (FMO) complex at physiological temperatures.
• To determine if quantum coherence at physiological temperatures is relevant to biological energy transport.
• To elucidate the role of protein dynamics in maintaining quantum coherence.

Main Methods:

• Experimental observation of quantum coherence in the FMO complex.
• Utilizing cryogenic temperatures (77 K) and physiological temperatures (e.g., 277 K).
• Spectroscopic analysis to measure coherence lifetimes.

Main Results:

• Quantum coherence was observed to survive in the FMO complex at physiological temperatures for at least 300 femtoseconds.
• This coherence lifetime is sufficient to influence biological energy transport.
• Correlated protein motions were identified as the mechanism preserving long coherence lifetimes, with protection remaining constant between 77 K and 277 K.

Conclusions:

• The wave-like energy transfer mechanism observed at low temperatures is relevant to biological function at physiological temperatures.
• Protein dynamics play a critical role in maintaining quantum coherence and mediating efficient energy transfer despite thermal fluctuations.
• This finding bridges the gap between quantum phenomena observed in vitro and their biological relevance.