Photosystem I P700 chlorophyll a apoprotein A2

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P09144 (PSAB_CHLRE) Reviewed, UniProtKB/Swiss-Prot

Last modified April 3, 2013. Version 120. History...

Clusters with 100%, 90%, 50% identity |

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Names·Attributes·General annotation·Ontologies·Sequence annotation·Sequences·References·Cross-refs·Entry info·Documents Customize order

Names and origin

Protein names

Recommended name:
Photosystem I P700 chlorophyll a apoprotein A2
EC=1.97.1.12

Alternative name(s):
PSI-B
PsaB

Gene names

Name:	psaB
Synonyms:	ps1a2

Encoded on

Plastid; Chloroplast

Organism

Chlamydomonas reinhardtii (Chlamydomonas smithii) [Reference proteome]

Taxonomic identifier

3055 [NCBI]

Taxonomic lineage

Eukaryota › Viridiplantae › Chlorophyta › Chlorophyceae › Chlamydomonadales › Chlamydomonadaceae › Chlamydomonas

Protein attributes

Sequence length	735 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	PsaA and PsaB bind P700, the primary electron donor of photosystem I (PSI), as well as the electron acceptors A0, A1 and FX. PSI is a plastocyanin/cytochrome c6-ferredoxin oxidoreductase, converting photonic excitation into a charge separation, which transfers an electron from the donor P700 chlorophyll pair to the spectroscopically characterized acceptors A0, A1, FX, FA and FB in turn. Oxidized P700 is reduced on the lumenal side of the thylakoid membrane by plastocyanin or cytochrome c6. HAMAP-Rule MF_00482 Both potential cofactor branches in PSI seem to be active; however, electron transfer seems to proceed preferentially down the path including the phylloquinone bound by PsaA. HAMAP-Rule MF_00482
Catalytic activity	Reduced plastocyanin + oxidized ferredoxin + light = oxidized plastocyanin + reduced ferredoxin. HAMAP-Rule MF_00482
Cofactor	P700 is a chlorophyll a/chlorophyll a' dimer, A0 is one or more chlorophyll a, A1 is one or both phylloquinones and FX is a shared 4Fe-4S iron-sulfur center By similarity.
Subunit structure	The PsaA/B heterodimer binds the P700 chlorophyll special pair and subsequent electron acceptors. PSI consists of a core antenna complex that captures photons, and an electron transfer chain that converts photonic excitation into a charge separation. The eukaryotic PSI reaction center is composed of at least 11 subunits.
Subcellular location	Plastid › chloroplast thylakoid membrane; Multi-pass membrane protein HAMAP-Rule MF_00482.
Sequence similarities	Belongs to the PsaA/PsaB family.

Ontologies

Keywords
Biological process	Electron transport Photosynthesis Transport
Cellular component	Chloroplast Membrane Photosystem I Plastid Thylakoid
Domain	Transmembrane Transmembrane helix
Ligand	4Fe-4S Chlorophyll Chromophore Iron Iron-sulfur Magnesium Metal-binding
Molecular function	Oxidoreductase
Technical term	Complete proteome Reference proteome
Gene Ontology (GO)
Biological_process	electron transport chain Inferred from electronic annotation. Source: UniProtKB-KW photosynthesis Inferred from electronic annotation. Source: HAMAP protein-chromophore linkage Inferred from electronic annotation. Source: UniProtKB-KW
Cellular_component	chloroplast thylakoid membrane Inferred from electronic annotation. Source: UniProtKB-SubCell integral to membrane Inferred from electronic annotation. Source: UniProtKB-KW photosystem I Inferred from electronic annotation. Source: UniProtKB-KW plastoglobule Inferred from electronic annotation. Source: EnsemblPlants/Gramene
Molecular_function	4 iron, 4 sulfur cluster binding Inferred from electronic annotation. Source: UniProtKB-KW chlorophyll binding Inferred from electronic annotation. Source: UniProtKB-KW electron carrier activity Inferred from electronic annotation. Source: HAMAP magnesium ion binding Inferred from electronic annotation. Source: HAMAP oxidoreductase activity Inferred from electronic annotation. Source: UniProtKB-KW
Complete GO annotation...

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Chain

1 – 735

735

Photosystem I P700 chlorophyll a apoprotein A2 HAMAP-Rule MF_00482

PRO_0000088609

Regions

Transmembrane

47 – 70

Helical; Name=I; Potential

Transmembrane

136 – 159

Helical; Name=II; Potential

Transmembrane

176 – 200

Helical; Name=III; Potential

Transmembrane

274 – 292

Helical; Name=IV; Potential

Transmembrane

331 – 354

Helical; Name=V; Potential

Transmembrane

370 – 396

Helical; Name=VI; Potential

Transmembrane

418 – 440

Helical; Name=VII; Potential

Transmembrane

518 – 536

Helical; Name=VIII; Potential

Transmembrane

576 – 597

Helical; Name=IX; Potential

Transmembrane

644 – 666

Helical; Name=X; Potential

Transmembrane

708 – 728

Helical; Name=XI; Potential

Sites

Metal binding

560

Iron-sulfur (4Fe-4S); shared with dimeric partner

Metal binding

569

Iron-sulfur (4Fe-4S); shared with dimeric partner By similarity

Metal binding

655

Magnesium (chlorophyll-a B1 axial ligand; P700 special pair)

Metal binding

663

Magnesium (chlorophyll-a B3 axial ligand) By similarity

Binding site

671

Chlorophyll-a B3 By similarity

Binding site

672

Phylloquinone B

Experimental info

Mutagenesis

559

P → A or L: Assembles functional PSI. Reaction center is somewhat unstable and interaction with psaC is impaired. The LEU mutant is less stable than the ALA mutant. Ref.8 Ref.11 Ref.13 Ref.15

Mutagenesis

560

C → H: Loss of PSI assembly and function. Ref.8 Ref.11 Ref.13 Ref.15

Mutagenesis

561

D → N: Loss of PSI assembly and function. Ref.9 Ref.11 Ref.13 Ref.15

Mutagenesis

563

P → L: Assembles functional PSI. Reaction center is somewhat unstable and interaction with psaC is impaired. Ref.9 Ref.11 Ref.13 Ref.15

Mutagenesis

565

R → E: Loss of PSI assembly and function. Ref.9 Ref.11 Ref.13 Ref.15

Mutagenesis

655

H → C, G, N or S: Contains somewhat decreased amounts of PSI, depending on the strain; significantly changes the spin density of the P700+ cation radical. Ref.10 Ref.11 Ref.12 Ref.13 Ref.15

Mutagenesis

655

H → D: Very little PSI detected. Ref.10 Ref.11 Ref.12 Ref.13 Ref.15

Mutagenesis

655

H → F or L: Loss of P700 function. Ref.10 Ref.11 Ref.12 Ref.13 Ref.15

Mutagenesis

655

H → Q: Impairment of P700 function. More severe; when associated with Q-676 in psaA. Ref.10 Ref.11 Ref.12 Ref.13 Ref.15

Mutagenesis

655

H → R: No PSI detected. Ref.10 Ref.11 Ref.12 Ref.13 Ref.15

Mutagenesis

672

W → F: Still able to photoaccumulate an electron on A1. Ref.11 Ref.13 Ref.15

Sequence conflict

Q → R in CAA29287. Ref.1

Sequence conflict

T → A in CAA29287. Ref.1

Sequence conflict

R → I in CAA29287. Ref.1

Sequence conflict

37 – 38

GM → VW in CAA29287. Ref.1

Sequence conflict

48 – 49

FA → IS in CAA29287. Ref.1

Sequence conflict

A → C in CAA29287. Ref.1

Sequence conflict

203

S → LQ in CAA29287. Ref.1

Sequence conflict

298

I → N in CAA29287. Ref.1

Sequence conflict

335

L → I in CAA29287. Ref.1

Sequence conflict

515

P → L Ref.1

Sequence conflict

515

P → L Ref.5

Sequences

Sequence

Length

Mass (Da)

Tools

P09144 [UniParc].

Last modified March 28, 2003. Version 4.
Checksum: 82F9914CE07A7908
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FASTA

735

82,109

        10         20         30         40         50         60 
MATKLFPKFS QGLAQDPTTR RIWYGLAMAH DFESHDGMTE ENLYQKIFAS HFGQLSIIFL 

        70         80         90        100        110        120 
WTSGNLFHVA WQGNFEQWVT DPVHIRPIAH AIWDPHFGQP AVEAFTRGGA SGPVNISTSG 

       130        140        150        160        170        180 
VYQWWYTIGM RTNQDLYVGS VFLALVSAIF LFAGWLHLQP NFQPSLSWFK DAESRLNHHL 

       190        200        210        220        230        240 
SGLFGVSSLA WTGHLVHVAI PESRGQHVGW DNFLSVLPHP QGLTPFFTGN WAAYAQSPDT 

       250        260        270        280        290        300 
ASHVFGTAQG SGQAILTFLG GFHPQTQSLW LTDMAHHHLA IAVIFIVAGH MYRTNFGIGH 

       310        320        330        340        350        360 
RMQAILEAHT PPSGSLGAGH KGLFDTVNNS LHFQLGLALA SVGTITSLVA QHMYSLPPYA 

       370        380        390        400        410        420 
FQAIDFTTQA ALYTHHQYIA GFIMCGAFAH GAIFFIRDYD PEQNKGNVLA RMLDHKEALI 

       430        440        450        460        470        480 
SHLSWVSLFL GFHTLGLYVH NDVMQAFGTP EKQILIEPVF AQWIQAAHGK ALYGFDFLLS 

       490        500        510        520        530        540 
SKTSAAFANG QSLWLPGWLD AINNNQNSLF LTIGPGDFLV HHAIALGLHT TTLILVKGAL 

       550        560        570        580        590        600 
DARGSKLMPD KKDFGYSFPC DGPGRGGTCD ISAYDAFYLA VFWMLNTIGW VTFYWHWKHL 

       610        620        630        640        650        660 
TLWQGNVAQF DESSTYLMGW LRDYLWLNSS QLINGYNPFG MNSLSVWAWT FLFGHLIYAT 

       670        680        690        700        710        720 
GFMFLISWRG YWQELIETLV WAHEKTPLAN LVYWKDKPVA LSIVQARLVG LAHFSVGYIF 

       730 
TYAAFLIAST SGRFG

« Hide

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"Structural and transcription analysis of two homologous genes for the P700 chlorophyll a-apoproteins in Chlamydomonas reinhardtii: evidence for in vivo trans-splicing." Kueck U., Choquet Y., Schneider M., Dron M., Bennoun P. EMBO J. 6:2185-2195(1987) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA]. Strain: CC-406.
[2]	"Revised sequence of the Chlamydomonas reinhardtii chloroplast gene psaB." Forsyth A.M., Redding K., Purton S. Submitted (NOV-2002) to the EMBL/GenBank/DDBJ databases Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
[3]	"Nucleotide diversity of the Chlamydomonas reinhardtii plastid genome: addressing the mutational-hazard hypothesis." Smith D.R., Lee R.W. BMC Evol. Biol. 9:120-120(2009) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: CC-503.
[4]	"Origin and evolution of the colonial Volvocales (Chlorophyceae) as inferred from multiple, chloroplast gene sequences." Nozaki H., Misawa K., Kajita T., Kato M., Nohara S., Watanabe M.M. Mol. Phylogenet. Evol. 17:256-268(2000) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 80-578. Strain: 137c / CC-125.
[5]	"Sequence of the chloroplast DNA region of Chlamydomonas reinhardii containing the gene of the large subunit of ribulose bisphosphate carboxylase and parts of its flanking genes." Dron M., Rahire M., Rochaix J.-D. J. Mol. Biol. 162:775-793(1982) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 493-735.
[6]	"Transformation of chloroplasts with the psaB gene encoding a polypeptide of the photosystem I reaction center." Bingham S.E., Xu R.H., Webber A.N. FEBS Lett. 292:137-140(1991) [PubMed] [Europe PMC] [Abstract] Cited for: PARTIAL NUCLEOTIDE SEQUENCE [GENOMIC DNA] (MUTANT AC-U-G-2.3). Strain: CC-2341.
[7]	"The Chlamydomonas reinhardtii plastid chromosome: islands of genes in a sea of repeats." Maul J.E., Lilly J.W., Cui L., dePamphilis C.W., Miller W., Harris E.H., Stern D.B. Plant Cell 14:2659-2679(2002) [PubMed] [Europe PMC] [Abstract] Cited for: IDENTIFICATION, COMPLETE PLASTID GENOME.
[8]	"Site-directed mutagenesis of the photosystem I reaction center in chloroplasts. The proline-cysteine motif." Webber A.N., Gibbs P.B., Ward J.B., Bingham S.E. J. Biol. Chem. 268:12990-12995(1993) [PubMed] [Europe PMC] [Abstract] Cited for: MUTAGENESIS OF PRO-559 AND CYS-560. Strain: 137c / CC-125 and CC-2341.
[9]	"Evidence that the FX domain in photosystem I interacts with the subunit PsaC: site-directed changes in PsaB destabilize the subunit interaction in Chlamydomonas reinhardtii." Rodday S.M., Webber A.N., Bingham S.E., Biggins J. Biochemistry 34:6328-6334(1995) [PubMed] [Europe PMC] [Abstract] Cited for: MUTAGENESIS OF ASP-561; PRO-563 AND ARG-565. Strain: 137c / CC-125.
[10]	"Site-directed mutations affecting the spectroscopic characteristics and midpoint potential of the primary donor in photosystem I." Webber A.N., Su H., Bingham S.E., Kaess H., Krabben L., Kuhn M., Jordan R., Schlodder E., Lubitz W. Biochemistry 35:12857-12863(1996) [PubMed] [Europe PMC] [Abstract] Cited for: MUTAGENESIS OF HIS-655. Strain: FuD7.
[11]	"A systematic survey of conserved histidines in the core subunits of photosystem I by site-directed mutagenesis reveals the likely axial ligands of P700." Redding K., MacMillan F., Leibl W., Brettel K., Hanley J., Rutherford A.W., Breton J., Rochaix J.-D. EMBO J. 17:50-60(1998) [PubMed] [Europe PMC] [Abstract] Cited for: MUTAGENESIS OF CONSERVED HISTIDINES. Strain: 137c / CC-125.
[12]	"Influence of the axial ligands on the spectral properties of P700 of photosystem I: a study of site-directed mutants." Krabben L., Schlodder E., Jordan R., Carbonera D., Giacometti G., Lee H., Webber A.N., Lubitz W. Biochemistry 39:13012-13025(2000) [PubMed] [Europe PMC] [Abstract] Cited for: MUTAGENESIS OF HIS-655. Strain: CC-2696.
[13]	"Evidence for two active branches for electron transfer in photosystem I." Guergova-Kuras M., Boudreaux B., Joliot A., Joliot P., Redding K. Proc. Natl. Acad. Sci. U.S.A. 98:4437-4442(2001) [PubMed] [Europe PMC] [Abstract] Cited for: MUTAGENESIS OF A1 PHYLLOQUINONE LIGANDS. Strain: 137c / CC-125.
[14]	"Reversed-phase HPLC determination of chlorophyll a' and phylloquinone in photosystem I of oxygenic photosynthetic organisms." Nakamura A., Akai M., Yoshida E., Taki T., Watanabe T. Eur. J. Biochem. 270:2446-2458(2003) [PubMed] [Europe PMC] [Abstract] Cited for: PRESENCE OF CHLOROPHYLL A' IN PSI. Strain: IAM C-9.
[15]	"Mutations in both sides of the photosystem I reaction center identify the phylloquinone observed by electron paramagnetic resonance spectroscopy." Boudreaux B., MacMillan F., Teutloff C., Agalarov R., Gu F., Grimaldi S., Bittl R., Brettel K., Redding K. J. Biol. Chem. 276:37299-37306(2001) [PubMed] [Europe PMC] [Abstract] Cited for: MUTAGENESIS OF A1 PHYLLOQUINONE LIGANDS. Strain: 137c / CC-125.

Cross-references

Sequence databases
EMBL GenBank DDBJ	X05848 Genomic DNA. Translation: CAA29287.1. U57326 Genomic DNA. Translation: AAN78307.1. FJ423446 Genomic DNA. Translation: ACJ50135.1. AB044470 Genomic DNA. Translation: BAB18396.1. J01399 Genomic DNA. No translation available. S67792 Genomic DNA. Translation: AAB20423.2. BK000554 Genomic DNA. Translation: DAA00949.2.
PIR	B28341. S18319.
RefSeq	NP_958404.1. NC_005353.1.
3D structure databases
ProteinModelPortal	P09144.
SMR	P09144. Positions 2-734.
ModBase	Search...
Protein-protein interaction databases
IntAct	P09144. 4 interactions.
Proteomic databases
PRIDE	P09144.
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Genome annotation databases
EnsemblPlants	DAA00949; DAA00949; DAA00949.
GeneID	2717038.
KEGG	cre:ChreCp048.
Phylogenomic databases
KO	K02690.
ProtClustDB	CHL00054.
Enzyme and pathway databases
BioCyc	CHLAMY:CHRECP048-MONOMER. MetaCyc:CHRECP048-MONOMER.
Family and domain databases
Gene3D	1.20.1130.10. 1 hit.
HAMAP	MF_00482. PSI_PsaB.
InterPro	IPR001280. PSI_PsaA/B. IPR020586. PSI_PsaA/B_CS. IPR006244. PSI_PsaB. [Graphical view]
Pfam	PF00223. PsaA_PsaB. 1 hit. [Graphical view]
PIRSF	PIRSF002905. PSI_A. 1 hit.
PRINTS	PR00257. PHOTSYSPSAAB.
TIGRFAMs	TIGR01336. psaB. 1 hit.
PROSITE	PS00419. PHOTOSYSTEM_I_PSAAB. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

PSAB_CHLRE

Accession

Primary (citable) accession number: P09144
Secondary accession number(s): B7U1I8

Q9GH44

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 1, 1989
Last sequence update:	March 28, 2003
Last modified:	April 3, 2013
This is version 120 of the entry and version 4 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Plant Protein Annotation Program

Relevant documents

SIMILARITY comments

Index of protein domains and families

Names·Attributes·General annotation·Ontologies·Sequence annotation·Sequences·References·Cross-refs·Entry info·Documents

Preferred order of sections

Names and origin

Protein attributes

General annotation (Comments)

Ontologies

Sequence annotation (Features)

Molecule processing

Regions

Sites

Experimental info

Sequences

References

Cross-references

Sequence databases

3D structure databases

Protein-protein interaction databases

Proteomic databases

Protocols and materials databases

Genome annotation databases

Phylogenomic databases

Enzyme and pathway databases

Family and domain databases

Entry information

Relevant documents