6LU1

Cyanobacterial PSI Monomer from T. elongatus by Single Particle CRYO-EM at 3.2 A Resolution

Summary for 6LU1

• Entry DOI: 10.2210/pdb6lu1/pdb
• EMDB information: 0977
• Descriptor: Photosystem I P700 chlorophyll a apoprotein A1, Photosystem I reaction center subunit XII, CHLOROPHYLL A, ... (17 entities in total)
• Functional Keywords: monomer, complex, photosystem, photosynthesis, membrane protein
• Biological source: Thermosynechococcus elongatus BP-1; More
• Total number of polymer chains: 10
• Total formula weight: 336876.13

Authors

Kurisu, G.,Coruh, O.,Tanaka, H.,Gerle, C.,Kawamoto, A.,Kato, T.,Namba, K.,Nowaczyk, M.M.,Rogner, M.,Misumi, Y.,Frank, A.,Eithar, E.M. (deposition date: 2020-01-24, release date: 2021-03-17, Last modification date: 2024-03-27)

Primary citation

Coruh, O.,Frank, A.,Tanaka, H.,Kawamoto, A.,El-Mohsnawy, E.,Kato, T.,Namba, K.,Gerle, C.,Nowaczyk, M.M.,Kurisu, G.
Cryo-EM structure of a functional monomeric Photosystem I from Thermosynechococcus elongatus reveals red chlorophyll cluster.
Commun Biol, 4:304-304, 2021

PubMed Abstract: A high-resolution structure of trimeric cyanobacterial Photosystem I (PSI) from Thermosynechococcus elongatus was reported as the first atomic model of PSI almost 20 years ago. However, the monomeric PSI structure has not yet been reported despite long-standing interest in its structure and extensive spectroscopic characterization of the loss of red chlorophylls upon monomerization. Here, we describe the structure of monomeric PSI from Thermosynechococcus elongatus BP-1. Comparison with the trimer structure gave detailed insights into monomerization-induced changes in both the central trimerization domain and the peripheral regions of the complex. Monomerization-induced loss of red chlorophylls is assigned to a cluster of chlorophylls adjacent to PsaX. Based on our findings, we propose a role of PsaX in the stabilization of red chlorophylls and that lipids of the surrounding membrane present a major source of thermal energy for uphill excitation energy transfer from red chlorophylls to P700.

PubMed: 33686186
DOI: 10.1038/s42003-021-01808-9

Experimental method

ELECTRON MICROSCOPY (3.2 Å)