Astrobiology Center, High Energy Accelerator Research Organization, Tohoku University, Akita Prefectural University, Tokyo University of Agriculture, National Institute for Basic Biology, University of Hyogo, National Institute of Polar Research, Chuo University, and other researchers have investigated green algae growing in Antarctica. We elucidated the mechanism by which Antarctic river laver performs photosynthesis using infrared rays.
Normally, plants and algae perform photosynthesis using visible light contained in sunlight.On the other hand, Antarctic river laver, which breeds in the extremely harsh environment of Antarctica, can use part of infrared light (far-red light), which has longer wavelengths than visible light, for photosynthesis with the same energy conversion efficiency as visible light. It says.In this study, we aimed to elucidate the mechanism of infrared photosynthesis in Antarctic kawanoe.
First, we identified a light-harvesting antenna protein that absorbs far-red light in cells of Antarctic kawanoe, and named it Pc-frLHC (Prasiola crispa far-red light harvesting Chl-binding protein complex). The molecular structure of Pc-frLHC was identified as a novel complex consisting of 11 proteins bound in a ring by single-particle analysis by cryo-electron microscopy.Each protein binds to 11 chlorophylls, of which 5 strongly interacting chlorophylls are involved in far-red light absorption.
As a result of analyzing the transfer process of far-red light energy absorbed by Pc-frLHC, we found that "uphill excitation energy transfer" from chlorophyll involved in far-red light absorption to normal chlorophyll (contrary to normal excitation energy transfer) , a phenomenon in which excitation energy is transferred from molecules with a lower energy level to molecules with a higher energy level).In this process, the research team believes that the energy of far-red light is converted into energy equivalent to that of visible light, and the photosynthetic reaction proceeds.
Many extrasolar planets are environments in which infrared rays are superior to visible light, so the existence of organisms that can use infrared rays for photosynthesis is also attracting attention in the field of astrobiology.The results of this study may also provide clues to the possibility of life on extrasolar planets.
Paper information:[Nature Communications] Uphill energy transfer mechanism for photosynthesis in an Antarctic alga
