Download MendeleyStructural insights into blue-green light utilization by marine green algal light harvesting complex II at 2.78 angstrom.
Seki, S., Nakaniwa, T., Castro-Hartmann, P., Sader, K., Kawamoto, A., Tanaka, H., Qian, P., Kurisu, G., Fujii, R.(2022) BBA Adv 2: 100064-100064
- PubMed: 37082593
- DOI: https://doi.org/10.1016/j.bbadva.2022.100064
- Primary Citation of Related Structures:
7WLM - PubMed Abstract:
Light-harvesting complex II (LHCII) present in plants and green algae absorbs solar energy to promote photochemical reactions. A marine green macroalga, Codium fragile , exhibits the unique characteristic of absorbing blue-green light from the sun during photochemical reactions while being underwater owing to the presence of pigment-altered LHCII called siphonaxanthin-chlorophyll a/b- binding protein (SCP). In this study, we determined the structure of SCP at a resolution of 2.78 Å using cryogenic electron microscopy. SCP has a trimeric structure, wherein each monomer containing two lutein and two chlorophyll a molecules in the plant-type LHCII are replaced by siphonaxanthin and its ester and two chlorophyll b molecules, respectively. Siphonaxanthin occupies the binding site in SCP having a polarity in the trimeric inner core, and exhibits a distorted conjugated chain comprising a carbonyl group hydrogen bonded to a cysteine residue of apoprotein. These features suggest that the siphonaxanthin molecule is responsible for the characteristic green absorption of SCP. The replaced chlorophyll b molecules extend the region of the stromal side chlorophyll b cluster, spanning two adjacent monomers.
Organizational Affiliation:
Division of Molecular Materials Science, Graduate School of Science, Osaka City University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
