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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)DescriptionActionsGraphical viewLength
Metal bindingi556Iron-sulfur (4Fe-4S); shared with dimeric partner1
Metal bindingi565Iron-sulfur (4Fe-4S); shared with dimeric partner1
Metal bindingi651Magnesium (chlorophyll-a B1 axial ligand; P700 special pair)By similarity1
Metal bindingi659Magnesium (chlorophyll-a B3 axial ligand)By similarity1
Binding sitei667Chlorophyll-a B3By similarity1
Binding sitei668Phylloquinone BBy similarity1

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 lineageiBacteriaCyanobacteriaSynechococcalesMerismopediaceaeSynechocystis
Proteomesi
  • UP000001425 Componenti: Chromosome

Subcellular locationi

Topology

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Transmembranei46 – 69Helical; Name=ISequence analysisAdd BLAST24
Transmembranei135 – 158Helical; Name=IISequence analysisAdd BLAST24
Transmembranei175 – 199Helical; Name=IIISequence analysisAdd BLAST25
Transmembranei273 – 291Helical; Name=IVSequence analysisAdd BLAST19
Transmembranei328 – 351Helical; Name=VSequence analysisAdd BLAST24
Transmembranei367 – 393Helical; Name=VISequence analysisAdd BLAST27
Transmembranei415 – 437Helical; Name=VIISequence analysisAdd BLAST23
Transmembranei514 – 532Helical; Name=VIIISequence analysisAdd BLAST19
Transmembranei572 – 593Helical; Name=IXSequence analysisAdd BLAST22
Transmembranei640 – 662Helical; Name=XSequence analysisAdd BLAST23
Transmembranei704 – 724Helical; Name=XISequence analysisAdd BLAST21

GO - Cellular componenti

Complete GO annotation...

Keywords - Cellular componenti

Membrane, Photosystem I, Thylakoid

Pathology & Biotechi

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi522L → P: No protein or PSI accumulate, unable to grow photoautotrophically. 1 Publication1
Mutagenesisi522L → V: No effect. 1 Publication1
Mutagenesisi536L → M: No effect. 1 Publication1
Mutagenesisi565C → D or H: Almost no protein accumulates. No PSI activity is present, unable to grow photoautotrophically. 1 Publication1
Mutagenesisi565C → S: Accumulates some protein and PSI, still does not grow photoautotrophically. 1 Publication1
Mutagenesisi595 – 596HL → 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 Publication2
Mutagenesisi600 – 602SGN → RCI: No protein or PSI accumulate, unable to grow photoautotrophically. 1 Publication3
Mutagenesisi609 – 611NST → KCI: No protein or PSI accumulate, unable to grow photoautotrophically. 1 Publication3
Mutagenesisi614 – 616MGW → ICA: No protein or PSI accumulate, unable to grow photoautotrophically. 1 Publication3
Mutagenesisi622 – 623WA → 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 Publication2
Mutagenesisi627 – 629QLI → 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 Publication3
Mutagenesisi632 – 633YN → 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 Publication2
Mutagenesisi638 – 639NN → 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 Publication2

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Initiator methionineiRemoved1 Publication
ChainiPRO_00000886572 – 731Photosystem I P700 chlorophyll a apoprotein A2Add BLAST730

Proteomic databases

PRIDEiP29255.

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 interactors.

Structurei

Secondary structure

1731
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Helixi10 – 13Combined sources4
Helixi19 – 26Combined sources8
Turni27 – 29Combined sources3
Helixi31 – 33Combined sources3
Helixi39 – 71Combined sources33
Helixi74 – 77Combined sources4
Turni81 – 83Combined sources3
Beta strandi87 – 90Combined sources4
Helixi98 – 104Combined sources7
Beta strandi113 – 115Combined sources3
Helixi120 – 126Combined sources7
Helixi132 – 155Combined sources24
Turni159 – 161Combined sources3
Helixi165 – 168Combined sources4
Helixi171 – 180Combined sources10
Turni181 – 183Combined sources3
Helixi184 – 196Combined sources13
Helixi198 – 201Combined sources4
Turni202 – 204Combined sources3
Turni209 – 211Combined sources3
Helixi212 – 214Combined sources3
Beta strandi217 – 220Combined sources4
Turni223 – 228Combined sources6
Helixi230 – 234Combined sources5
Turni263 – 265Combined sources3
Helixi270 – 285Combined sources16
Helixi286 – 289Combined sources4
Beta strandi294 – 296Combined sources3
Helixi301 – 305Combined sources5
Turni317 – 319Combined sources3
Helixi320 – 326Combined sources7
Helixi328 – 350Combined sources23
Helixi363 – 394Combined sources32
Turni398 – 403Combined sources6
Helixi405 – 411Combined sources7
Helixi413 – 443Combined sources31
Helixi447 – 449Combined sources3
Helixi456 – 463Combined sources8
Turni464 – 466Combined sources3
Helixi475 – 477Combined sources3
Turni482 – 487Combined sources6
Helixi491 – 499Combined sources9
Beta strandi503 – 506Combined sources4
Helixi511 – 536Combined sources26
Helixi547 – 549Combined sources3
Helixi569 – 600Combined sources32
Helixi604 – 609Combined sources6
Helixi613 – 619Combined sources7
Turni620 – 627Combined sources8
Helixi628 – 630Combined sources3
Helixi641 – 662Combined sources22
Helixi665 – 681Combined sources17
Beta strandi682 – 684Combined sources3
Beta strandi691 – 693Combined sources3
Helixi699 – 729Combined sources31

3D structure databases

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

Family & Domainsi

Sequence similaritiesi

Belongs to the PsaA/PsaB family.Curated

Keywords - Domaini

Transmembrane, Transmembrane helix

Phylogenomic databases

HOGENOMiHOG000276868.
InParanoidiP29255.
KOiK02690.
OMAiAQFNESS.
PhylomeDBiP29255.

Family and domain databases

Gene3Di1.20.1130.10. 1 hit.
HAMAPiMF_00482. PSI_PsaB. 1 hit.
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)DescriptionActionsGraphical viewLength
Sequence conflicti502T → I AA sequence (PubMed:9268309).Curated1
Sequence conflicti537 – 538DA → ES in CAA41630 (PubMed:1932686).Curated2

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
PDB entryMethodResolution (Å)ChainPositionsPDBsum
4KT0X-ray2.80B1-731[»]
4L6VX-ray3.802/B/b1-731[»]
ProteinModelPortaliP29255.
SMRiP29255.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

IntActiP29255. 3 interactors.

Proteomic databases

PRIDEiP29255.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

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

Phylogenomic databases

HOGENOMiHOG000276868.
InParanoidiP29255.
KOiK02690.
OMAiAQFNESS.
PhylomeDBiP29255.

Enzyme and pathway databases

BioCyciMetaCyc:PSAB-MONOMER.

Family and domain databases

Gene3Di1.20.1130.10. 1 hit.
HAMAPiMF_00482. PSI_PsaB. 1 hit.
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...

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: November 2, 2016
This is version 139 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.