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Protein

Photosystem I P700 chlorophyll a apoprotein A2

Gene

psaB

Organism
Synechocystis sp. (strain PCC 6803 / Kazusa)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

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.

Catalytic activityi

Reduced plastocyanin + oxidized ferredoxin + light = oxidized plastocyanin + reduced ferredoxin.

Cofactori

Note: PSI electron transfer chain: 5 chlorophyll a, 1 chlorophyll a', 2 phylloquinones and 3 4Fe-4S clusters. PSI core antenna: 90 chlorophyll a, 22 carotenoids, 3 phospholipids and 1 galactolipid. 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

Sites

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Metal bindingi556 – 5561Iron-sulfur (4Fe-4S); shared with dimeric partner
Metal bindingi565 – 5651Iron-sulfur (4Fe-4S); shared with dimeric partner
Metal bindingi651 – 6511Magnesium (chlorophyll-a B1 axial ligand; P700 special pair)By similarity
Metal bindingi659 – 6591Magnesium (chlorophyll-a B3 axial ligand)By similarity
Binding sitei667 – 6671Chlorophyll-a B3By similarity
Binding sitei668 – 6681Phylloquinone BBy similarity

GO - Molecular functioni

GO - Biological processi

Complete GO annotation...

Keywords - Molecular functioni

Oxidoreductase

Keywords - Biological processi

Electron transport, Photosynthesis, Transport

Keywords - Ligandi

4Fe-4S, Chlorophyll, Chromophore, Iron, Iron-sulfur, Magnesium, Metal-binding

Enzyme and pathway databases

BioCyciMetaCyc:PSAB-MONOMER.

Names & Taxonomyi

Protein namesi
Recommended name:
Photosystem I P700 chlorophyll a apoprotein A2 (EC:1.97.1.12)
Alternative name(s):
PsaB
Gene namesi
Name:psaB
Ordered Locus Names:slr1835
OrganismiSynechocystis sp. (strain PCC 6803 / Kazusa)
Taxonomic identifieri1111708 [NCBI]
Taxonomic lineageiBacteriaCyanobacteriaOscillatoriophycideaeChroococcalesSynechocystis
Proteomesi
  • UP000001425 Componenti: Chromosome

Subcellular locationi

Topology

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Transmembranei46 – 6924Helical; Name=ISequence analysisAdd
BLAST
Transmembranei135 – 15824Helical; Name=IISequence analysisAdd
BLAST
Transmembranei175 – 19925Helical; Name=IIISequence analysisAdd
BLAST
Transmembranei273 – 29119Helical; Name=IVSequence analysisAdd
BLAST
Transmembranei328 – 35124Helical; Name=VSequence analysisAdd
BLAST
Transmembranei367 – 39327Helical; Name=VISequence analysisAdd
BLAST
Transmembranei415 – 43723Helical; Name=VIISequence analysisAdd
BLAST
Transmembranei514 – 53219Helical; Name=VIIISequence analysisAdd
BLAST
Transmembranei572 – 59322Helical; Name=IXSequence analysisAdd
BLAST
Transmembranei640 – 66223Helical; Name=XSequence analysisAdd
BLAST
Transmembranei704 – 72421Helical; Name=XISequence analysisAdd
BLAST

GO - Cellular componenti

Complete GO annotation...

Keywords - Cellular componenti

Membrane, Photosystem I, Thylakoid

Pathology & Biotechi

Mutagenesis

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Mutagenesisi522 – 5221L → P: No protein or PSI accumulate, unable to grow photoautotrophically. 1 Publication
Mutagenesisi522 – 5221L → V: No effect. 1 Publication
Mutagenesisi536 – 5361L → M: No effect. 1 Publication
Mutagenesisi565 – 5651C → D or H: Almost no protein accumulates. No PSI activity is present, unable to grow photoautotrophically. 1 Publication
Mutagenesisi565 – 5651C → S: Accumulates some protein and PSI, still does not grow photoautotrophically. 1 Publication
Mutagenesisi595 – 5962HL → CI: PSI less stably assembled than wild-type, possible decrease in ability to accept electrons from cytochrome c6. C-594 is exposed on complex surface. 1 Publication
Mutagenesisi600 – 6023SGN → RCI: No protein or PSI accumulate, unable to grow photoautotrophically. 1 Publication
Mutagenesisi609 – 6113NST → KCI: No protein or PSI accumulate, unable to grow photoautotrophically. 1 Publication
Mutagenesisi614 – 6163MGW → ICA: No protein or PSI accumulate, unable to grow photoautotrophically. 1 Publication
Mutagenesisi622 – 6232WA → CR: Decreases PSI levels, has slow autotrophic growth, unable to accept electrons in vitro from cytochrome c6. C-621 is exposed on complex surface. 1 Publication
Mutagenesisi627 – 6293QLI → HCS: Decreases PSI levels but no change in ability of complex to accept electrons from cytochrome c6. C-627 is exposed on complex surface. 1 Publication
Mutagenesisi632 – 6332YN → CI: Greatly decreases levels of PSI, cells do not grow photoautotrophically. Unable to accept electrons from cytochrome c6 in vitro. C-631 is exposed on complex surface. 1 Publication
Mutagenesisi638 – 6392NN → CS: PSI assembles less stably than in wild-type but no change in ability of complex to accept electrons from cytochrome c6. C-637 is exposed on complex surface. 1 Publication

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Initiator methionineiRemoved1 Publication
Chaini2 – 731730Photosystem I P700 chlorophyll a apoprotein A2PRO_0000088657Add
BLAST

Interactioni

Subunit structurei

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 cyanobacterial PSI reaction center is composed of one copy each of PsaA,B,C,D,E,F,I,J,K,L,M and X, and forms trimeric complexes (By similarity).By similarity

Protein-protein interaction databases

IntActiP29255. 3 interactions.

Structurei

Secondary structure

1
731
Legend: HelixTurnBeta strand
Show more details
Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Helixi10 – 134Combined sources
Helixi19 – 268Combined sources
Turni27 – 293Combined sources
Helixi31 – 333Combined sources
Helixi39 – 7133Combined sources
Helixi74 – 774Combined sources
Turni81 – 833Combined sources
Beta strandi87 – 904Combined sources
Helixi98 – 1047Combined sources
Beta strandi113 – 1153Combined sources
Helixi120 – 1267Combined sources
Helixi132 – 15524Combined sources
Turni159 – 1613Combined sources
Helixi165 – 1684Combined sources
Helixi171 – 18010Combined sources
Turni181 – 1833Combined sources
Helixi184 – 19613Combined sources
Helixi198 – 2014Combined sources
Turni202 – 2043Combined sources
Turni209 – 2113Combined sources
Helixi212 – 2143Combined sources
Beta strandi217 – 2204Combined sources
Turni223 – 2286Combined sources
Helixi230 – 2345Combined sources
Turni263 – 2653Combined sources
Helixi270 – 28516Combined sources
Helixi286 – 2894Combined sources
Beta strandi294 – 2963Combined sources
Helixi301 – 3055Combined sources
Turni317 – 3193Combined sources
Helixi320 – 3267Combined sources
Helixi328 – 35023Combined sources
Helixi363 – 39432Combined sources
Turni398 – 4036Combined sources
Helixi405 – 4117Combined sources
Helixi413 – 44331Combined sources
Helixi447 – 4493Combined sources
Helixi456 – 4638Combined sources
Turni464 – 4663Combined sources
Helixi475 – 4773Combined sources
Turni482 – 4876Combined sources
Helixi491 – 4999Combined sources
Beta strandi503 – 5064Combined sources
Helixi511 – 53626Combined sources
Helixi547 – 5493Combined sources
Helixi569 – 60032Combined sources
Helixi604 – 6096Combined sources
Helixi613 – 6197Combined sources
Turni620 – 6278Combined sources
Helixi628 – 6303Combined sources
Helixi641 – 66222Combined sources
Helixi665 – 68117Combined sources
Beta strandi682 – 6843Combined sources
Beta strandi691 – 6933Combined sources
Helixi699 – 72931Combined sources

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
4KT0X-ray2.80B1-731[»]
4L6VX-ray3.802/B/b1-731[»]
ProteinModelPortaliP29255.
SMRiP29255. Positions 2-730.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Sequence similaritiesi

Belongs to the PsaA/PsaB family.Curated

Keywords - Domaini

Transmembrane, Transmembrane helix

Phylogenomic databases

HOGENOMiHOG000276868.
InParanoidiP29255.
KOiK02690.
OMAiAQFNESS.
OrthoDBiEOG60W7PS.
PhylomeDBiP29255.

Family and domain databases

Gene3Di1.20.1130.10. 1 hit.
HAMAPiMF_00482. PSI_PsaB.
InterProiIPR001280. PSI_PsaA/B.
IPR020586. PSI_PsaA/B_CS.
IPR006244. PSI_PsaB.
[Graphical view]
PfamiPF00223. PsaA_PsaB. 1 hit.
[Graphical view]
PIRSFiPIRSF002905. PSI_A. 1 hit.
PRINTSiPR00257. PHOTSYSPSAAB.
SUPFAMiSSF81558. SSF81558. 1 hit.
TIGRFAMsiTIGR01336. psaB. 1 hit.
PROSITEiPS00419. PHOTOSYSTEM_I_PSAAB. 1 hit.
[Graphical view]

Sequencei

Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

P29255-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MATKFPKFSQ DLAQDPTTRR IWYGIATAHD FETHDGMTEE NLYQKIFASH
60 70 80 90 100
FGHIAIIFLW TSGTLFHVAW QGNFEQWIKD PLNIRPIAHA IWDPHFGEGA
110 120 130 140 150
VNAFTQAGAS NPVNIAYSGV YHWFYTIGMT TNQELYSGAV FLLVLASLFL
160 170 180 190 200
FAGWLHLQPK FRPSLAWFKN AESRLNHHLA GLFGVSSLAW AGHLVHVAIP
210 220 230 240 250
EARGQHVGWD NFLSTPPHPA GLMPFFTGNW GVYAADPDTA GHIFGTSEGA
260 270 280 290 300
GTAILTFLGG FHPQTESLWL TDIAHHHLAI AVIFIIAGHM YRTNWGIGHS
310 320 330 340 350
IKEILNAHKG PLTGAGHTNL YDTINNSLHF QLGLALASLG VITSLVAQHM
360 370 380 390 400
YSLPSYAFIA QDHTTQAALY THHQYIAGFL MVGAFAHGAI FFVRDYDPVA
410 420 430 440 450
NKDNVLARML EHKEALISHL SWVSLFLGFH TLGLYVHNDV VVAFGTPEKQ
460 470 480 490 500
ILIEPVFAQW IQATSGKALY GFDVLLSNPD SIASTTGAAW LPGWLDAINS
510 520 530 540 550
GTNSLFLTIG PGDFLVHHAI ALGLHTTALI LIKGALDARG SKLMPDKKDF
560 570 580 590 600
GYSFPCDGPG RGGTCDISAW DAFYLAMFWM LNTLGWLTFY WHWKHLGVWS
610 620 630 640 650
GNVAQFNENS TYLMGWFRDY LWANSAQLIN GYNPYGVNNL SVWAWMFLFG
660 670 680 690 700
HLVWATGFMF LISWRGYWQE LIETIVWAHE RTPLANLVRW KDKPVALSIV
710 720 730
QARLVGLAHF TVGYVLTYAA FLIASTAGKF G
Length:731
Mass (Da):81,292
Last modified:January 23, 2007 - v4
Checksum:iBEED6B43CC5B3DD9
GO

Experimental Info

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Sequence conflicti502 – 5021T → I AA sequence (PubMed:9268309).Curated
Sequence conflicti537 – 5382DA → ES in CAA41630 (PubMed:1932686).Curated

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
X58825 Genomic DNA. Translation: CAA41630.1.
BA000022 Genomic DNA. Translation: BAA17438.1.
PIRiS18243.

Genome annotation databases

EnsemblBacteriaiBAA17438; BAA17438; BAA17438.
KEGGisyn:slr1835.
PATRICi23838742. VBISynSp132158_0937.

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
X58825 Genomic DNA. Translation: CAA41630.1.
BA000022 Genomic DNA. Translation: BAA17438.1.
PIRiS18243.

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
4KT0X-ray2.80B1-731[»]
4L6VX-ray3.802/B/b1-731[»]
ProteinModelPortaliP29255.
SMRiP29255. Positions 2-730.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

IntActiP29255. 3 interactions.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsemblBacteriaiBAA17438; BAA17438; BAA17438.
KEGGisyn:slr1835.
PATRICi23838742. VBISynSp132158_0937.

Phylogenomic databases

HOGENOMiHOG000276868.
InParanoidiP29255.
KOiK02690.
OMAiAQFNESS.
OrthoDBiEOG60W7PS.
PhylomeDBiP29255.

Enzyme and pathway databases

BioCyciMetaCyc:PSAB-MONOMER.

Family and domain databases

Gene3Di1.20.1130.10. 1 hit.
HAMAPiMF_00482. PSI_PsaB.
InterProiIPR001280. PSI_PsaA/B.
IPR020586. PSI_PsaA/B_CS.
IPR006244. PSI_PsaB.
[Graphical view]
PfamiPF00223. PsaA_PsaB. 1 hit.
[Graphical view]
PIRSFiPIRSF002905. PSI_A. 1 hit.
PRINTSiPR00257. PHOTSYSPSAAB.
SUPFAMiSSF81558. SSF81558. 1 hit.
TIGRFAMsiTIGR01336. psaB. 1 hit.
PROSITEiPS00419. PHOTOSYSTEM_I_PSAAB. 1 hit.
[Graphical view]
ProtoNetiSearch...

Publicationsi

« Hide 'large scale' publications
  1. "Expression of photosynthesis genes in the cyanobacterium Synechocystis sp. PCC 6803: psaA-psaB and psbA transcripts accumulate in dark-grown cells."
    Smart L.B., McIntosh L.
    Plant Mol. Biol. 17:959-971(1991) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
  2. "Sequence analysis of the genome of the unicellular cyanobacterium Synechocystis sp. strain PCC6803. II. Sequence determination of the entire genome and assignment of potential protein-coding regions."
    Kaneko T., Sato S., Kotani H., Tanaka A., Asamizu E., Nakamura Y., Miyajima N., Hirosawa M., Sugiura M., Sasamoto S., Kimura T., Hosouchi T., Matsuno A., Muraki A., Nakazaki N., Naruo K., Okumura S., Shimpo S.
    , Takeuchi C., Wada T., Watanabe A., Yamada M., Yasuda M., Tabata S.
    DNA Res. 3:109-136(1996) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
    Strain: PCC 6803 / Kazusa.
  3. "Topography of the photosystem I core proteins of the cyanobacterium Synechocystis sp. PCC 6803."
    Sun J., Xu Q., Chitnis V.P., Jin P., Chitnis P.R.
    J. Biol. Chem. 272:21793-21802(1997) [PubMed] [Europe PMC] [Abstract]
    Cited for: PROTEIN SEQUENCE OF 2-8; 9-13; 295-300; 304-310; 449-454; 462-467 AND 498-504, TOPOLOGY.
  4. "Mutational analysis of the structure and biogenesis of the photosystem I reaction center in the cyanobacterium Synechocystis sp. PCC 6803."
    Smart L.B., Warren P.V., Golbeck J.H., McIntosh L.
    Proc. Natl. Acad. Sci. U.S.A. 90:1132-1136(1993) [PubMed] [Europe PMC] [Abstract]
    Cited for: MUTAGENESIS OF LEU-522; LEU-536 AND CYS-565.
  5. "Oxidizing side of the cyanobacterial photosystem I. Evidence for interaction between the electron donor proteins and a luminal surface helix of the PsaB subunit."
    Sun J., Xu W., Hervas M., Navarro J.A., De La Rosa M.A., Chitnis P.R.
    J. Biol. Chem. 274:19048-19054(1999) [PubMed] [Europe PMC] [Abstract]
    Cited for: MUTAGENESIS OF LUMENAL J LOOP (HIS-595 TO ASN-639).
  6. "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.

Entry informationi

Entry nameiPSAB_SYNY3
AccessioniPrimary (citable) accession number: P29255
Secondary accession number(s): P73398
Entry historyi
Integrated into UniProtKB/Swiss-Prot: December 1, 1992
Last sequence update: January 23, 2007
Last modified: March 16, 2016
This is version 136 of the entry and version 4 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programProkaryotic Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

3D-structure, Complete proteome, Direct protein sequencing, Reference proteome

Documents

  1. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  2. SIMILARITY comments
    Index of protein domains and families
  3. Synechocystis PCC 6803
    Synechocystis (strain PCC 6803): entries and gene names

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.