UniProtKB - P0A408 (PSAB_SYNEL)
Protein
Photosystem I P700 chlorophyll a apoprotein A2
Gene
psaB
Organism
Synechococcus elongatus
Status
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
- hν + oxidized [2Fe-2S]-[ferredoxin] + reduced [plastocyanin] = oxidized [plastocyanin] + reduced [2Fe-2S]-[ferredoxin]UniRule annotationEC:1.97.1.12UniRule annotation
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.
Sites
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Metal bindingi | 566 | Iron-sulfur (4Fe-4S); shared with dimeric partnerUniRule annotation | 1 | |
Metal bindingi | 575 | Iron-sulfur (4Fe-4S); shared with dimeric partnerUniRule annotation | 1 | |
Metal bindingi | 661 | Magnesium (chlorophyll-a B1 axial ligand; P700 special pair)UniRule annotation | 1 | |
Metal bindingi | 669 | Magnesium (chlorophyll-a B3 axial ligand)UniRule annotation | 1 | |
Binding sitei | 677 | Chlorophyll-a B3UniRule annotation | 1 | |
Binding sitei | 678 | Phylloquinone BUniRule annotation | 1 |
GO - Molecular functioni
- 4 iron, 4 sulfur cluster binding Source: UniProtKB-KW
- chlorophyll binding Source: UniProtKB-KW
- electron transfer activity Source: UniProtKB-UniRule
- magnesium ion binding Source: UniProtKB-UniRule
GO - Biological processi
- photosynthesis Source: UniProtKB-UniRule
- protein-chromophore linkage Source: UniProtKB-KW
Keywordsi
Molecular function | Oxidoreductase |
Biological process | Electron transport, Photosynthesis, Transport |
Ligand | 4Fe-4S, Chlorophyll, Chromophore, Iron, Iron-sulfur, Magnesium, Metal-binding |
Names & Taxonomyi
Protein namesi | Recommended name: Photosystem I P700 chlorophyll a apoprotein A2UniRule annotation (EC:1.97.1.12UniRule annotation)Alternative name(s): PsaBUniRule annotation |
Gene namesi | Name:psaBUniRule annotation |
Organismi | Synechococcus elongatus |
Taxonomic identifieri | 32046 [NCBI] |
Taxonomic lineagei | Bacteria › Cyanobacteria › Synechococcales › Synechococcaceae › Synechococcus |
Subcellular locationi
Other locations
Plasma Membrane
- plasma membrane-derived thylakoid membrane Source: UniProtKB-SubCell
Other locations
- integral component of membrane Source: UniProtKB-KW
- photosystem I Source: UniProtKB-KW
Topology
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Topological domaini | 2 – 38 | CytoplasmicCuratedAdd BLAST | 37 | |
Transmembranei | 39 – 70 | Helical; Name=IUniRule annotationAdd BLAST | 32 | |
Topological domaini | 71 – 131 | Lumenal, thylakoidCuratedAdd BLAST | 61 | |
Transmembranei | 132 – 156 | Helical; Name=IIUniRule annotationAdd BLAST | 25 | |
Topological domaini | 157 – 172 | CytoplasmicCuratedAdd BLAST | 16 | |
Transmembranei | 173 – 195 | Helical; Name=IIIUniRule annotationAdd BLAST | 23 | |
Topological domaini | 196 – 269 | Lumenal, thylakoidCuratedAdd BLAST | 74 | |
Transmembranei | 270 – 287 | Helical; Name=IVUniRule annotationAdd BLAST | 18 | |
Topological domaini | 288 – 334 | CytoplasmicCuratedAdd BLAST | 47 | |
Transmembranei | 335 – 358 | Helical; Name=VUniRule annotationAdd BLAST | 24 | |
Topological domaini | 359 – 368 | Lumenal, thylakoidCurated | 10 | |
Transmembranei | 369 – 400 | Helical; Name=VIUniRule annotationAdd BLAST | 32 | |
Topological domaini | 401 – 419 | CytoplasmicCuratedAdd BLAST | 19 | |
Transmembranei | 420 – 449 | Helical; Name=VIIUniRule annotationAdd BLAST | 30 | |
Topological domaini | 450 – 520 | Lumenal, thylakoidCuratedAdd BLAST | 71 | |
Transmembranei | 521 – 545 | Helical; Name=VIIIUniRule annotationAdd BLAST | 25 | |
Topological domaini | 546 – 578 | CytoplasmicCuratedAdd BLAST | 33 | |
Transmembranei | 579 – 610 | Helical; Name=IXUniRule annotationAdd BLAST | 32 | |
Topological domaini | 611 – 650 | Lumenal, thylakoidCuratedAdd BLAST | 40 | |
Transmembranei | 651 – 672 | Helical; Name=XUniRule annotationAdd BLAST | 22 | |
Topological domaini | 673 – 708 | CytoplasmicCuratedAdd BLAST | 36 | |
Transmembranei | 709 – 737 | Helical; Name=XIUniRule annotationAdd BLAST | 29 | |
Topological domaini | 738 – 741 | Lumenal, thylakoidCurated | 4 |
Keywords - Cellular componenti
Membrane, Photosystem I, ThylakoidPTM / Processingi
Molecule processing
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Initiator methioninei | RemovedBy similarity | |||
ChainiPRO_0000088651 | 2 – 741 | Photosystem I P700 chlorophyll a apoprotein A2Add BLAST | 740 |
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.
Family & Domainsi
Sequence similaritiesi
Belongs to the PsaA/PsaB family.UniRule annotation
Keywords - Domaini
Transmembrane, Transmembrane helixFamily and domain databases
Gene3Di | 1.20.1130.10, 1 hit |
HAMAPi | MF_00482, PSI_PsaB, 1 hit |
InterProi | View protein in InterPro IPR001280, PSI_PsaA/B IPR020586, PSI_PsaA/B_CS IPR036408, PSI_PsaA/B_sf IPR006244, PSI_PsaB |
Pfami | View protein in Pfam PF00223, PsaA_PsaB, 1 hit |
PIRSFi | PIRSF002905, PSI_A, 1 hit |
PRINTSi | PR00257, PHOTSYSPSAAB |
SUPFAMi | SSF81558, SSF81558, 1 hit |
TIGRFAMsi | TIGR01336, psaB, 1 hit |
PROSITEi | View protein in PROSITE PS00419, PHOTOSYSTEM_I_PSAAB, 1 hit |
i Sequence
Sequence statusi: Complete.
: The displayed sequence is further processed into a mature form. Sequence processingi
P0A408-1 [UniParc]FASTAAdd to basket
10 20 30 40 50
MATKFPKFSQ DLAQDPTTRR IWYAIAMAHD FESHDGMTEE NLYQKIFASH
60 70 80 90 100
FGHLAIIFLW VSGSLFHVAW QGNFEQWVQD PVNTRPIAHA IWDPQFGKAA
110 120 130 140 150
VDAFTQAGAS NPVDIAYSGV YHWWYTIGMR TNGDLYQGAI FLLILASLAL
160 170 180 190 200
FAGWLHLQPK FRPSLSWFKN AESRLNHHLA GLFGVSSLAW AGHLIHVAIP
210 220 230 240 250
ESRGQHVGWD NFLSTMPHPA GLAPFFTGNW GVYAQNPDTA SHVFGTAQGA
260 270 280 290 300
GTAILTFLGG FHPQTESLWL TDMAHHHLAI AVLFIVAGHM YRTQFGIGHS
310 320 330 340 350
IKEMMDAKDF FGTKVEGPFN MPHQGIYETY NNSLHFQLGW HLACLGVITS
360 370 380 390 400
LVAQHMYSLP PYAFIAQDHT TMAALYTHHQ YIAGFLMVGA FAHGAIFLVR
410 420 430 440 450
DYDPAQNKGN VLDRVLQHKE AIISHLSWVS LFLGFHTLGL YVHNDVVVAF
460 470 480 490 500
GTPEKQILIE PVFAQFIQAA HGKLLYGFDT LLSNPDSIAS TAWPNYGNVW
510 520 530 540 550
LPGWLDAINS GTNSLFLTIG PGDFLVHHAI ALGLHTTTLI LVKGALDARG
560 570 580 590 600
SKLMPDKKDF GYAFPCDGPG RGGTCDISAW DAFYLAMFWM LNTIGWVTFY
610 620 630 640 650
WHWKHLGVWE GNVAQFNESS TYLMGWLRDY LWLNSSQLIN GYNPFGTNNL
660 670 680 690 700
SVWAWMFLFG HLVWATGFMF LISWRGYWQE LIETLVWAHE RTPLANLVRW
710 720 730 740
KDKPVALSIV QARLVGLAHF SVGYILTYAA FLIASTAAKF G
Sequence databases
Select the link destinations: EMBLi GenBanki DDBJi Links Updated | X63768 Genomic DNA Translation: CAA45305.1 |
Similar proteinsi
Cross-referencesi
Sequence databases
Select the link destinations: EMBLi GenBanki DDBJi Links Updated | X63768 Genomic DNA Translation: CAA45305.1 |
3D structure databases
SMRi | P0A408 |
ModBasei | Search... |
Family and domain databases
Gene3Di | 1.20.1130.10, 1 hit |
HAMAPi | MF_00482, PSI_PsaB, 1 hit |
InterProi | View protein in InterPro IPR001280, PSI_PsaA/B IPR020586, PSI_PsaA/B_CS IPR036408, PSI_PsaA/B_sf IPR006244, PSI_PsaB |
Pfami | View protein in Pfam PF00223, PsaA_PsaB, 1 hit |
PIRSFi | PIRSF002905, PSI_A, 1 hit |
PRINTSi | PR00257, PHOTSYSPSAAB |
SUPFAMi | SSF81558, SSF81558, 1 hit |
TIGRFAMsi | TIGR01336, psaB, 1 hit |
PROSITEi | View protein in PROSITE PS00419, PHOTOSYSTEM_I_PSAAB, 1 hit |
ProtoNeti | Search... |
MobiDBi | Search... |
Entry informationi
Entry namei | PSAB_SYNEL | |
Accessioni | P0A408Primary (citable) accession number: P0A408 Secondary accession number(s): P25897 | |
Entry historyi | Integrated into UniProtKB/Swiss-Prot: | March 15, 2005 |
Last sequence update: | January 23, 2007 | |
Last modified: | April 7, 2021 | |
This is version 76 of the entry and version 2 of the sequence. See complete history. | ||
Entry statusi | Reviewed (UniProtKB/Swiss-Prot) | |
Annotation program | Prokaryotic Protein Annotation Program |