7SUT

Light harvesting phycobiliprotein HaPE645 from the cryptophyte Hemiselmis andersenii CCMP644

7SUT の概要

• エントリーDOI: 10.2210/pdb7sut/pdb
• 分子名称: HaPE645 alpha-1 subunit, PHYCOCYANOBILIN, Phycoerythrin550 beta subunit, ... (11 entities in total)
• 機能のキーワード: phycobiliprotein, antenna, light harvesting, cryptophyte, algae, globin, calm, carsp, photosynthesis, phycoerythrin, hemiselmis
• 由来する生物種: Hemiselmis andersenii; 詳細
• タンパク質・核酸の鎖数: 8
• 化学式量合計: 117220.06

構造登録者

Rathbone, H.W.,Michie, K.A.,Laos, A.L.,Curmi, P.M.G. (登録日: 2021-11-18, 公開日: 2023-10-25, 最終更新日: 2026-03-04)

主引用文献

Rathbone, H.W.,Laos, A.J.,Michie, K.A.,Iranmanesh, H.,Biazik, J.,Goodchild, S.C.,Thordarson, P.,Green, B.R.,Curmi, P.M.G.
Molecular dissection of the soluble photosynthetic antenna from the cryptophyte alga Hemiselmis andersenii.
Commun Biol, 6:1158-1158, 2023

PubMed Abstract: Cryptophyte algae have a unique phycobiliprotein light-harvesting antenna that fills a spectral gap in chlorophyll absorption from photosystems. However, it is unclear how the antenna transfers energy efficiently to these photosystems. We show that the cryptophyte Hemiselmis andersenii expresses an energetically complex antenna comprising three distinct spectrotypes of phycobiliprotein, each composed of two αβ protomers but with different quaternary structures arising from a diverse α subunit family. We report crystal structures of the major phycobiliprotein from each spectrotype. Two-thirds of the antenna consists of open quaternary form phycobiliproteins acting as primary photon acceptors. These are supplemented by a newly discovered open-braced form (~15%), where an insertion in the α subunit produces ~10 nm absorbance red-shift. The final components (~15%) are closed forms with a long wavelength spectral feature due to substitution of a single chromophore. This chromophore is present on only one β subunit where asymmetry is dictated by the corresponding α subunit. This chromophore creates spectral overlap with chlorophyll, thus bridging the energetic gap between the phycobiliprotein antenna and the photosystems. We propose that the macromolecular organization of the cryptophyte antenna consists of bulk open and open-braced forms that transfer excitations to photosystems via this bridging closed form phycobiliprotein.

PubMed: 37957226
DOI: 10.1038/s42003-023-05508-4

実験手法

X-RAY DIFFRACTION (1.49 Å)