5ZZN

Crystal structure of photosystem II from an SQDG-deficient mutant of Thermosynechococcus elongatus

Summary for 5ZZN

• Entry DOI: 10.2210/pdb5zzn/pdb
• Descriptor: Photosystem II protein D1 1, Photosystem II reaction center protein K, Photosystem II reaction center protein L, ... (41 entities in total)
• Functional Keywords: photosynthesis, electron transport
• Biological source: Thermosynechococcus elongatus (strain BP-1); More
• Total number of polymer chains: 38
• Total formula weight: 756987.91

Authors

Nakajima, Y.,Umena, Y.,Nagao, R.,Endo, K.,Kobayashi, K.,Akita, F.,Suga, M.,Wada, H.,Noguchi, T.,Shen, J.R. (deposition date: 2018-06-03, release date: 2018-08-01, Last modification date: 2023-11-22)

Primary citation

Nakajima, Y.,Umena, Y.,Nagao, R.,Endo, K.,Kobayashi, K.,Akita, F.,Suga, M.,Wada, H.,Noguchi, T.,Shen, J.R.
Thylakoid membrane lipid sulfoquinovosyl-diacylglycerol (SQDG) is required for full functioning of photosystem II inThermosynechococcus elongatus.
J. Biol. Chem., 293:14786-14797, 2018

PubMed Abstract: Sulfoquinovosyl-diacylglycerol (SQDG) is one of the four lipids present in the thylakoid membranes. Depletion of SQDG causes different degrees of effects on photosynthetic growth and activities in different organisms. Four SQDG molecules bind to each monomer of photosystem II (PSII), but their role in PSII function has not been characterized in detail, and no PSII structure without SQDG has been reported. We analyzed the activities of PSII from an SQDG-deficient mutant of the cyanobacterium by various spectroscopic methods, which showed that depletion of SQDG partially impaired the PSII activity by impairing secondary quinone (Q) exchange at the acceptor site. We further solved the crystal structure of the PSII dimer from the SQDG deletion mutant at 2.1 Å resolution and found that all of the four SQDG-binding sites were occupied by other lipids, most likely PG molecules. Replacement of SQDG at a site near the head of Q provides a possible explanation for the Q impairment. The replacement of two SQDGs located at the monomer-monomer interface by other lipids decreased the stability of the PSII dimer, resulting in an increase in the amount of PSII monomer in the mutant. The present results thus suggest that although SQDG binding in all of the PSII-binding sites is necessary to fully maintain the activity and stability of PSII, replacement of SQDG by other lipids can partially compensate for their functions.

PubMed: 30076221
DOI: 10.1074/jbc.RA118.004304

Experimental method

X-RAY DIFFRACTION (2.1 Å)