Family

Photosystem II CP43 reaction centre protein (IPR005869)

Short name: PSII_PsbC

Family relationships

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.

PSII is a multisubunit protein-pigment complex containing polypeptides both intrinsic and extrinsic to the photosynthetic membrane [PMID: 12518057, PMID: 15100025]. Within the core of the complex, the chlorophyll and beta-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 10 kDa), and are involved in PSII assembly, stabilisation, dimerisation, and photo-protection [PMID: 14871485].

This family represents the intrinsic antenna protein CP43 (PsbC), which is one of two such proteins found in the reaction centre of PSII, both of which can bind to chlorophyll 'a' and beta-carotene, passing the excitation energy on to the reaction centre [PMID: 12163077].

GO terms

Biological Process

GO:0015979 photosynthesis
GO:0009772 photosynthetic electron transport in photosystem II

Molecular Function

GO:0016168 chlorophyll binding
GO:0045156 electron transporter, transferring electrons within the cyclic electron transport pathway of photosynthesis activity

Cellular Component

GO:0016020 membrane
GO:0009523 photosystem II

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
TIGRFAMs
HAMAP