MetaCyc Polypeptide: CP26

Gene: LHCB5 Accession Number: CHLREDRAFT_184397 (MetaCyc)

Synonyms: 184397, Minor chlorophyll a-b binding protein of photosystem II

Species: Chlamydomonas reinhardtii

Component of: photosystem II (extended summary available)

CP26 is a light harvesting monomeric protein which can bind both chlorophylls and xanthophylls. It is located between the reaction center core and the outer antenna [Barber99]. This protein along with other minor chlorophyll-binding proteins forms a connecting module between LHCII and the PSII reaction center [Minagawa01]. It was suggested to play a role in photoprotection as xanthophylls involved in dissipating excess excitation energy as heat (Qe quenching) bind to CP26 [DemingAdams90]. Indeed, CP26 can regulate the transduction of energy by mediating a rapid response to excess light energy throught the xanthophyll cycle [Minagawa01].

Phylogenetically, CP26 diverged from LHCII before the LHCII polypeptides diverged to form Lhcb1, Lhcb2, and Lhcb3 in eukaryotes [Green96].

Citations: [Merchant07]

Locations: chloroplast, chloroplast thylakoid membrane

Map Position: [550,135 <- 552,534]

Molecular Weight of Polypeptide: 30.71 kD (from nucleotide sequence)

Unification Links: DIP:DIP-48402N, Pride:Q9FEK6, Protein Model Portal:Q9FEK6, String:3055.EDP01264, UniProt:Q9FEK6

Relationship Links: InterPro:IN-FAMILY:IPR001344, InterPro:IN-FAMILY:IPR022796, InterPro:IN-FAMILY:IPR023329, Panther:IN-FAMILY:PTHR21649, Pfam:IN-FAMILY:PF00504

Gene-Reaction Schematic

Gene-Reaction Schematic

GO Terms:
Cellular Component:
GO:0009507 - chloroplast []
GO:0009535 - chloroplast thylakoid membrane []

MultiFun Terms: metabolismenergy production/transport

Revised 29-Apr-2011 by Weerasinghe D

Subunit of: photosystem II

Synonyms: PSII complex, PSII-LHCII supercomplex

Species: Chlamydomonas reinhardtii

Subunit composition of photosystem II = [LHCBM9][LHCBM8][LHCBM7][LHCBM6][LHCBM5][LHCBM4][LHCBM3][LHCBM2][LHCBM1][LHCB5][LHCB4][(PSBQ)(PSBP1)(PSBO)][([(PsbK)(PsbC)([PsbT][PsbR][PsbM][PsbL][PsbJ][PsbH][(PsbB)([PsbA][(PsbE)(PsbD)])])][PSBW][PsbZ][PSBO])2]
         Chlorophyll a-b binding protein of LHCII = LHCBM9 (summary available)
         Chlorophyll a-b binding protein of LHCII = LHCBM8 (summary available)
         Major light-harvesting complex II protein m7 = LHCBM7 (summary available)
         Chloropyll a-b binding protein of LHCII type I = LHCBM6 (summary available)
         Chlorophyll a-b binding protein of LHCII = LHCBM5 (summary available)
         Chloropyll a-b binding protein of LHCII = LHCBM4 (summary available)
         Light-harvesting chlorophyll-a/b binding protein LhcII-1.3 = LHCBM3 (summary available)
         Light-harvesting chlorophyll-a/b binding protein LhcII-3 = LHCBM2 (summary available)
         Chlorophyll a-b binding protein of LHCII = LHCBM1 (summary available)
         CP26 = LHCB5 (summary available)
         Chlorophyll a-b binding protein CP29 = LHCB4 (summary available)
         OEC complex = (PSBQ)(PSBP1)(PSBO) (summary available)
                 Oxygen-evolving enhancer protein 3 = PSBQ (summary available)
                 Oxygen-evolving enhancer protein 2 of photosystem II = PSBP1 (summary available)
                 Oxygen-evolving enhancer protein 1 = PSBO (summary available)
         PS II core dimer = ([(PsbK)(PsbC)([PsbT][PsbR][PsbM][PsbL][PsbJ][PsbH][(PsbB)([PsbA][(PsbE)(PsbD)])])][PSBW][PsbZ][PSBO])2 (extended summary available)
                 PS II core monomer (complete) = ([PsbK][PsbC][(PsbT)(PsbR)(PsbM)(PsbL)(PsbJ)(PsbH)([PsbB][(PsbA)([PsbE][PsbD])])])(PSBW)(PsbZ)(PSBO)
                         PS II core monomer = (PsbK)(PsbC)([PsbT][PsbR][PsbM][PsbL][PsbJ][PsbH][(PsbB)([PsbA][(PsbE)(PsbD)])]) (summary available)
                                 Photosystem II reaction center protein K = PsbK (summary available)
                                 CP43 = PsbC (summary available)
                                 CP43-less PS II core monomer = (PsbT)(PsbR)(PsbM)(PsbL)(PsbJ)(PsbH)([PsbB][(PsbA)([PsbE][PsbD])]) (summary available)
                                         Photosystem II reaction center protein T = PsbT (summary available)
                                         10 kDa photosystem II polypeptide = PsbR (summary available)
                                         Photosystem II reaction center protein M = PsbM
                                         Photosystem II reaction center protein L = PsbL
                                         Photosystem II reaction center protein J = PsbJ (summary available)
                                         Photosystem II reaction center protein H = PsbH
                                         PS II RC - CP47 complex = (PsbB)([PsbA][(PsbE)(PsbD)]) (summary available)
                                                 Photosystem II CP47 chlorophyll apoprotein = PsbB (summary available)
                                                 PS II RC = (PsbA)([PsbE][PsbD])
                                                         Photosystem Q(B) protein = PsbA (summary available)
                                                         cytb559-D2 complex = (PsbE)(PsbD) (summary available)
                                                                 cytochrome b-559 α-subunit = PsbE (summary available)
                                                                 Photosystem II D2 protein = PsbD (summary available)
                         Photosystem II reaction center W protein = PSBW
                         Photosystem II reaction center protein Z = PsbZ (summary available)
                         Oxygen-evolving enhancer protein 1 = PSBO (summary available)

The process of photosynthesis which is central to the presence of life on earth involves the interplay of several reactions. Chloroplasts are the pivotal organelles in this process and they are highly compartmentalized for this function which is mediated by three light dependet complexes. Photosystem I (PSI), photosystem II (PSII), and the cytochrome b6f complex are the three light-dependent complexes, located in the thylakoid membranes, a detailed network of flattened vesicles [Uniacke07].

Photosystem II is a water oxidizing multisubunit protein complex [Barber02]. A cluster of four manganese atoms bound to the lumenal surface of the complex catalyzes the water oxidizing reaction which is powered by solar energy. The Mn cluster is sequentially oxidized by P680 and a chlorophyll a molecule that acts as the primary electron donor, with pheophytin acting as the primary electron acceptor [Allakhverdiev11]. All these redox active components of PSII are bound to the two structurally related proteins known as D1 and D2. Associated with the D1/D2 heterodimer are two chlorophyll proteins CP43 and CP47 and at least three extrinsic proteins that protect and optimize the activity of the Mn cluster [Buchel99]. These proteins, cytochrome b559 and some other subunits make up the core complex [Hankamer01].

Citations: [Jun09, Hankamer01a]

Locations: thylakoid membrane, chloroplast

GO Terms:
Cellular Component:
GO:0009507 - chloroplast []
GO:0042651 - thylakoid membrane []

Created 12-Jan-2010 by May P, MPI-MP
Revised 17-May-2011 by Weerasinghe D

Enzymatic reaction of: photosystem II

Traceable author statement to experimental support

EC Number:

Transport reaction diagram for photosystem II

In Pathways: superpathway of photosynthetic hydrogen production, photosynthesis light reactions


Schematic showing introns, exons and/or isoforms of LHCB5


Allakhverdiev11: Allakhverdiev SI, Tsuchiya T, Watabe K, Kojima A, Los DA, Tomo T, Klimov VV, Mimuro M (2011). "Redox potentials of primary electron acceptor quinone molecule (QA)- and conserved energetics of photosystem II in cyanobacteria with chlorophyll a and chlorophyll d." Proc Natl Acad Sci U S A 108(19);8054-8. PMID: 21521792

Barber02: Barber J (2002). "Photosystem II: a multisubunit membrane protein that oxidises water." Curr Opin Struct Biol 12(4);523-30. PMID: 12163077

Barber99: Barber J, Kuhlbrandt W (1999). "Photosystem II." Curr Opin Struct Biol 9(4);469-75. PMID: 10449373

Buchel99: Buchel C, Barber J, Ananyev G, Eshaghi S, Watt R, Dismukes C (1999). "Photoassembly of the manganese cluster and oxygen evolution from monomeric and dimeric CP47 reaction center photosystem II complexes." Proc Natl Acad Sci U S A 96(25);14288-93. PMID: 10588698

DemingAdams90: Deming-Adams B (1990). "Carotenoids and photoprotection in plants: a role for the xanthophyll zeaxanthin." Biochim. Biophys. Acta.

Dey97: Dey, PM, Harborne, JB "Plant Biochemistry." Academic Press 1997.

Green96: Green BR, Durnford DG (1996). "THE CHLOROPHYLL-CAROTENOID PROTEINS OF OXYGENIC PHOTOSYNTHESIS." Annu Rev Plant Physiol Plant Mol Biol 47;685-714. PMID: 15012305

Hankamer01: Hankamer B, Morris E, Nield J, Gerle C, Barber J (2001). "Three-dimensional structure of the photosystem II core dimer of higher plants determined by electron microscopy." J Struct Biol 135(3);262-9. PMID: 11722166

Hankamer01a: Hankamer B, Morris E, Nield J, Carne A, Barber J (2001). "Subunit positioning and transmembrane helix organisation in the core dimer of photosystem II." FEBS Lett 504(3);142-51. PMID: 11532446

Jun09: Jun Minagawa (2009). "Light-Harvesting Proteins." Chapter 14. In: The Chlamydomonas Sourcebook. Second Edition.

Merchant07: Merchant SS, Prochnik SE, Vallon O, Harris EH, Karpowicz SJ, Witman GB, Terry A, Salamov A, Fritz-Laylin LK, Marechal-Drouard L, Marshall WF, Qu LH, Nelson DR, Sanderfoot AA, Spalding MH, Kapitonov VV, Ren Q, Ferris P, Lindquist E, Shapiro H, Lucas SM, Grimwood J, Schmutz J, Cardol P, Cerutti H, Chanfreau G, Chen CL, Cognat V, Croft MT, Dent R, Dutcher S, Fernandez E, Fukuzawa H, Gonzalez-Ballester D, Gonzalez-Halphen D, Hallmann A, Hanikenne M, Hippler M, Inwood W, Jabbari K, Kalanon M, Kuras R, Lefebvre PA, Lemaire SD, Lobanov AV, Lohr M, Manuell A, Meier I, Mets L, Mittag M, Mittelmeier T, Moroney JV, Moseley J, Napoli C, Nedelcu AM, Niyogi K, Novoselov SV, Paulsen IT, Pazour G, Purton S, Ral JP, Riano-Pachon DM, Riekhof W, Rymarquis L, Schroda M, Stern D, Umen J, Willows R, Wilson N, Zimmer SL, Allmer J, Balk J, Bisova K, Chen CJ, Elias M, Gendler K, Hauser C, Lamb MR, Ledford H, Long JC, Minagawa J, Page MD, Pan J, Pootakham W, Roje S, Rose A, Stahlberg E, Terauchi AM, Yang P, Ball S, Bowler C, Dieckmann CL, Gladyshev VN, Green P, Jorgensen R, Mayfield S, Mueller-Roeber B, Rajamani S, Sayre RT, Brokstein P, Dubchak I, Goodstein D, Hornick L, Huang YW, Jhaveri J, Luo Y, Martinez D, Ngau WC, Otillar B, Poliakov A, Porter A, Szajkowski L, Werner G, Zhou K, Grigoriev IV, Rokhsar DS, Grossman AR (2007). "The Chlamydomonas genome reveals the evolution of key animal and plant functions." Science 318(5848);245-50. PMID: 17932292

Minagawa01: Minagawa J, Han KC, Dohmae N, Takio K, Inoue Y (2001). "Molecular characterization and gene expression of lhcb5 gene encoding CP26 in the light-harvesting complex II of Chlamydomonas reinhardtii." Plant Mol Biol 46(3);277-87. PMID: 11488475

Uniacke07: Uniacke J, Zerges W (2007). "Photosystem II assembly and repair are differentially localized in Chlamydomonas." Plant Cell 19(11);3640-54. PMID: 18055604

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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