F
IPR003372

Photosystem II PsbL

InterPro entry
Short namePSII_PsbL
Overlapping
homologous
superfamilies
 

Description

Oxygenic photosynthesis uses two multi-subunit photosystems (I and II) located in the cell membranes of cyanobacteria and in the thylakoid membranes of chloroplasts in plants and algae. Photosystem II (PSII) has a P680 reaction centre containing chlorophyll 'a' that uses light energy to carry out the oxidation (splitting) of water molecules, and to produce ATP via a proton pump. Photosystem I (PSI) has a P700 reaction centre containing chlorophyll that takes the electron and associated hydrogen donated from PSII to reduce NADP+ to NADPH. Both ATP and NADPH are subsequently used in the light-independent reactions to convert carbon dioxide to glucose using the hydrogen atom extracted from water by PSII, releasing oxygen as a by-product
[7]
.

PSII is a multisubunit protein-pigment complex containing polypeptides both intrinsic and extrinsic to the photosynthetic membrane
[7, 1, 2, 6]
. Within the core of the complex, the chlorophyll and β-carotene pigments are mainly bound to the antenna proteins CP43 (PsbC) and CP47 (PsbB), which pass the excitation energy on to the reaction centre proteins D1 (Qb, PsbA) and D2 (Qa, PsbD) that bind all the redox-active cofactors involved in the energy conversion process. The PSII oxygen-evolving complex (OEC) oxidises water to provide protons for use by PSI, and consists of OEE1 (PsbO), OEE2 (PsbP) and OEE3 (PsbQ). The remaining subunits in PSII are of low molecular weight (less than 10kDa), and are involved in PSII assembly, stabilisation, dimerisation, and photo-protection
[3]
.

This entry represents the low molecular weight transmembrane protein PsbL found in PSII. PsbL is located in a gene cluster with PsbE, PsbF and PsbJ (PsbEFJL). Both PsbL and PsbJ (
IPR002682
) are essential for proper assembly of the OEC. Mutations in PsbL prevent the formation of both PSII core dimers and PSII-light harvesting complex
[4]
. In addition, both PsbL and PsbJ are involved in the unidirectional flow of electrons, where PsbJ regulates the forward electron flow from D2 (Qa) to the plastoquinone pool, and PsbL prevents the reduction of PSII by back electron flow from plastoquinol protecting PSII from photo-inactivation
[5]
.

References

1.Crystal structure of oxygen-evolving photosystem II from Thermosynechococcus vulcanus at 3.7-A resolution. Kamiya N, Shen JR. Proc. Natl. Acad. Sci. U.S.A. 100, 98-103, (2003). View articlePMID: 12518057

2.The evolutionary development of the protein complement of photosystem 2. Raymond J, Blankenship RE. Biochim. Biophys. Acta 1655, 133-9, (2004). PMID: 15100025

3.The low molecular mass subunits of the photosynthetic supracomplex, photosystem II. Shi LX, Schroder WP. Biochim. Biophys. Acta 1608, 75-96, (2004). PMID: 14871485

4.Protein assembly of photosystem II and accumulation of subcomplexes in the absence of low molecular mass subunits PsbL and PsbJ. Suorsa M, Regel RE, Paakkarinen V, Battchikova N, Herrmann RG, Aro EM. Eur. J. Biochem. 271, 96-107, (2004). View articlePMID: 14686923

5.Photosystem II proteins PsbL and PsbJ regulate electron flow to the plastoquinone pool. Ohad I, Dal Bosco C, Herrmann RG, Meurer J. Biochemistry 43, 2297-308, (2004). View articlePMID: 14979726

6.Thylakoid membrane lipid sulfoquinovosyl-diacylglycerol (SQDG) is required for full functioning of photosystem II in <i>Thermosynechococcus elongatus</i>. Nakajima Y, Umena Y, Nagao R, Endo K, Kobayashi K, Akita F, Suga M, Wada H, Noguchi T, Shen JR. J Biol Chem 293, 14786-14797, (2018). PMID: 30076221

7.Structural insights into photosystem II assembly. Zabret J, Bohn S, Schuller SK, Arnolds O, Moller M, Meier-Credo J, Liauw P, Chan A, Tajkhorshid E, Langer JD, Stoll R, Krieger-Liszkay A, Engel BD, Rudack T, Schuller JM, Nowaczyk MM. Nat Plants 7, 524-538, (2021). View articlePMID: 33846594

GO terms

Cross References

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