Temperature and ionic strength effects on the chlorosome light-harvesting antenna complex

Area of Science:

• Biophysics
• Photosynthesis Research
• Materials Science

Background:

• Chlorosomes are large, efficient light-harvesting antenna complexes in green photosynthetic bacteria.
• They consist of over 150,000 self-assembled bacteriochlorophylls (BChls) with minimal protein content.
• Their unique structure makes them promising for biohybrid solar cell applications.

Purpose of the Study:

• To investigate the effects of temperature and ionic strength on chlorosome viability.
• To understand structural changes under varying environmental conditions.
• To assess the potential of chlorosomes in biohybrid solar devices.

Main Methods:

• Small-angle neutron scattering (SANS).
• Dynamic light scattering (DLS).
• Thermal and pH stability tests.

Main Results:

• Chlorosomes maintain structural integrity up to 75°C.
• Ionic strength induces reversible aggregation, more effectively with divalent ions.
• High temperatures (98°C) damage the baseplate but preserve pigments.
• Chlorosomes are stable within a pH range of 5.5 to 11.0.

Conclusions:

• Chlorosomes exhibit remarkable thermal and pH stability.
• Environmental factors like salt concentration influence their aggregation state.
• Pigments remain intact even after baseplate destruction, suggesting potential for pigment extraction and use.
• These findings are crucial for understanding chlorosome function and optimizing their use in biohybrid solar energy systems.