8WQP

Cryo-EM structure of T. pseudonana PyShell helical tube

Summary for 8WQP

• Entry DOI: 10.2210/pdb8wqp/pdb
• EMDB information: 37751
• Descriptor: Diatom the pyrenoid shell protein (1 entity in total)
• Functional Keywords: marine diatoms, photosynthesis, co2-concentrating mechanism, pyrenoids, plant protein
• Biological source: Thalassiosira pseudonana (Marine diatom, Cyclotella nana)
• Total number of polymer chains: 2
• Total formula weight: 49972.04

Authors

Kawamoto, A.,Tohda, R.,Gerle, C.,Kurisu, G. (deposition date: 2023-10-12, release date: 2024-10-09, Last modification date: 2024-11-06)

Primary citation

Shimakawa, G.,Demulder, M.,Flori, S.,Kawamoto, A.,Tsuji, Y.,Nawaly, H.,Tanaka, A.,Tohda, R.,Ota, T.,Matsui, H.,Morishima, N.,Okubo, R.,Wietrzynski, W.,Lamm, L.,Righetto, R.D.,Uwizeye, C.,Gallet, B.,Jouneau, P.H.,Gerle, C.,Kurisu, G.,Finazzi, G.,Engel, B.D.,Matsuda, Y.
Diatom pyrenoids are encased in a protein shell that enables efficient CO 2 fixation.
Cell, 187:5919-, 2024

PubMed Abstract: Pyrenoids are subcompartments of algal chloroplasts that increase the efficiency of Rubisco-driven CO fixation. Diatoms fix up to 20% of global CO, but their pyrenoids remain poorly characterized. Here, we used in vivo photo-crosslinking to identify pyrenoid shell (PyShell) proteins, which we localized to the pyrenoid periphery of model pennate and centric diatoms, Phaeodactylum tricornutum and Thalassiosira pseudonana. In situ cryo-electron tomography revealed that pyrenoids of both diatom species are encased in a lattice-like protein sheath. Single-particle cryo-EM yielded a 2.4-Å-resolution structure of an in vitro TpPyShell1 lattice, which showed how protein subunits interlock. T. pseudonana TpPyShell1/2 knockout mutants had no PyShell sheath, altered pyrenoid morphology, and a high-CO requiring phenotype, with reduced photosynthetic efficiency and impaired growth under standard atmospheric conditions. The structure and function of the diatom PyShell provide a molecular view of how CO is assimilated in the ocean, a critical ecosystem undergoing rapid change.

PubMed: 39357521
DOI: 10.1016/j.cell.2024.09.013

Experimental method

ELECTRON MICROSCOPY (2.4 Å)