9QFP: Monomeric Photosystem I Cryo-EM structure
Monomeric Photosystem I Cryo-EM structure at 1.8 A resolution. Determined by electron microscopy at 1.74 Å resolution. Released 30 Sept 2026.
- Method
- Electron microscopy
- Resolution
- 1.74 Å
- Organism
- Thermosynechococcus vestitus BP-1
- Chains
- 11
- Atoms
- 25,572
- Mol. weight
- 348.96 kDa
- Ligands
- LMT, CLA, PQN, CL0
- Released
- 30 Sept 2026
Explore 9QFP in 3D
Show helices and sheets
RCSB PDB
PDBe
Secondary structure: helices and β-sheets
9QFP contains 135 α-helices and 58 β-strands across 11 chains. Residue ranges use author residue numbering, as in the PDB file, from PDBe. To see them in 3D, choose the Cartoon representation with Secondary structure coloring: helices, sheets and coils get different colors.
Chain A: 46 helices, 18 β-strands
| Element | Residues | Length | Sheet |
|---|
| β-strand | 16-18 | 3 | 1 |
| α-helix | 26-29 | 4 | |
| α-helix | 36-38 | 3 | |
| β-strand | 44 | 1 | 2 |
| α-helix | 46-53 | 8 | |
| α-helix | 58-60 | 3 | |
| α-helix | 65-96 | 32 | |
| α-helix | 100-105 | 6 | |
| β-strand | 113-115 | 3 | 3 |
| α-helix | 123-126 | 4 | |
| β-strand | 128-129 | 2 | 4 |
| β-strand | 135-136 | 2 | 4 |
| β-strand | 137-138 | 2 | 3 |
| α-helix | 139 | 1 | |
| α-helix | 143-149 | 7 | |
| α-helix | 155-181 | 27 | |
| β-strand | 183-185 | 3 | 1 |
| α-helix | 187-190 | 4 | |
| α-helix | 193-199 | 7 | |
| α-helix | 200-207 | 8 | |
| α-helix | 208-215 | 8 | |
| α-helix | 216-220 | 5 | |
| α-helix | 221-228 | 8 | |
| α-helix | 233-235 | 3 | |
| α-helix | 237-238 | 2 | |
| α-helix | 239-244 | 6 | |
| α-helix | 246-252 | 7 | |
| α-helix | 262-264 | 3 | |
| α-helix | 265-268 | 4 | |
| α-helix | 272-275 | 4 | |
| α-helix | 294-311 | 18 | |
| β-strand | 315 | 1 | 5 |
| β-strand | 323 | 1 | 5 |
| α-helix | 325-331 | 7 | |
| α-helix | 344-350 | 7 | |
| α-helix | 352-376 | 25 | |
| α-helix | 387-418 | 32 | |
| α-helix | 422-424 | 3 | |
| α-helix | 429-434 | 6 | |
| α-helix | 437-467 | 31 | |
| α-helix | 471-473 | 3 | |
| β-strand | 475 | 1 | 6 |
| β-strand | 480 | 1 | 6 |
| α-helix | 485-495 | 11 | |
| β-strand | 498 | 1 | 7 |
| β-strand | 502 | 1 | 7 |
| α-helix | 511-513 | 3 | |
| β-strand | 518-520 | 3 | 8 |
| β-strand | 523-526 | 4 | 8 |
| α-helix | 533-558 | 26 | |
| α-helix | 569-572 | 4 | |
| α-helix | 591-620 | 30 | |
| β-strand | 623-625 | 3 | 8 |
| β-strand | 631-633 | 3 | 8 |
| α-helix | 639-642 | 4 | |
| α-helix | 646-648 | 3 | |
| α-helix | 649-655 | 7 | |
| α-helix | 656-657 | 2 | |
| α-helix | 659-662 | 4 | |
| α-helix | 670-690 | 21 | |
| α-helix | 694-710 | 17 | |
| β-strand | 718 | 1 | 2 |
| α-helix | 721-723 | 3 | |
| α-helix | 724-754 | 31 | |
Chain B: 51 helices, 14 β-strands
| Element | Residues | Length | Sheet |
|---|
| β-strand | 3 | 1 | 9 |
| α-helix | 10-13 | 4 | |
| β-strand | 17 | 1 | 10 |
| α-helix | 19-27 | 9 | |
| α-helix | 31-33 | 3 | |
| α-helix | 39-71 | 33 | |
| α-helix | 74-79 | 6 | |
| α-helix | 85-86 | 2 | |
| β-strand | 87-90 | 4 | 11 |
| α-helix | 98-104 | 7 | |
| β-strand | 113-115 | 3 | 11 |
| α-helix | 116 | 1 | |
| α-helix | 120-126 | 7 | |
| α-helix | 132-155 | 24 | |
| α-helix | 159-161 | 3 | |
| α-helix | 162-164 | 3 | |
| α-helix | 165-168 | 4 | |
| α-helix | 171-177 | 7 | |
| α-helix | 178-185 | 8 | |
| α-helix | 186-193 | 8 | |
| α-helix | 194-198 | 5 | |
| α-helix | 199-202 | 4 | |
| α-helix | 212-214 | 3 | |
| α-helix | 223-227 | 5 | |
| α-helix | 230-234 | 5 | |
| α-helix | 237-239 | 3 | |
| β-strand | 261 | 1 | 12 |
| β-strand | 268 | 1 | 12 |
| α-helix | 270-287 | 18 | |
| β-strand | 291 | 1 | 13 |
| β-strand | 299 | 1 | 13 |
| α-helix | 301-305 | 5 | |
| β-strand | 309-310 | 2 | 14 |
| β-strand | 313-314 | 2 | 14 |
| α-helix | 318-320 | 3 | |
| α-helix | 326-332 | 7 | |
| α-helix | 334-358 | 25 | |
| α-helix | 365-367 | 3 | |
| α-helix | 369-400 | 32 | |
| α-helix | 405-407 | 3 | |
| α-helix | 411-417 | 7 | |
| α-helix | 419-449 | 31 | |
| α-helix | 453-455 | 3 | |
| β-strand | 459 | 1 | 15 |
| α-helix | 462-470 | 9 | |
| α-helix | 474-476 | 3 | |
| α-helix | 481-483 | 3 | |
| α-helix | 488-491 | 4 | |
| α-helix | 501-509 | 9 | |
| α-helix | 521-546 | 26 | |
| α-helix | 557-560 | 4 | |
| α-helix | 579-609 | 31 | |
| α-helix | 613-619 | 7 | |
| α-helix | 623-625 | 3 | |
| α-helix | 626-632 | 7 | |
| α-helix | 633-634 | 2 | |
| α-helix | 636-639 | 4 | |
| β-strand | 642-643 | 2 | 16 |
| β-strand | 646-647 | 2 | 16 |
| α-helix | 651-672 | 22 | |
| α-helix | 675-691 | 17 | |
| α-helix | 695-697 | 3 | |
| β-strand | 703 | 1 | 10 |
| α-helix | 706-708 | 3 | |
| α-helix | 709-739 | 31 | |
Chain C: 3 helices, 4 β-strands
| Element | Residues | Length | Sheet |
|---|
| β-strand | 4-8 | 5 | 17 |
| α-helix | 16-20 | 5 | |
| β-strand | 27-30 | 4 | 18 |
| β-strand | 38-41 | 4 | 18 |
| α-helix | 45-47 | 3 | |
| α-helix | 53-57 | 5 | |
| β-strand | 65-68 | 4 | 17 |
Chain D: 9 helices, 9 β-strands
| Element | Residues | Length | Sheet |
|---|
| β-strand | 7 | 1 | 19 |
| α-helix | 8-9 | 2 | |
| β-strand | 10 | 1 | 20 |
| α-helix | 21-24 | 4 | |
| β-strand | 27-34 | 8 | 19 |
| β-strand | 38-41 | 4 | 20 |
| β-strand | 47-50 | 4 | 20 |
| α-helix | 51 | 1 | |
| β-strand | 53-59 | 7 | 19 |
| α-helix | 62-68 | 7 | |
| α-helix | 69-73 | 5 | |
| α-helix | 74-76 | 3 | |
| β-strand | 82-86 | 5 | 19 |
| β-strand | 92-96 | 5 | 19 |
| β-strand | 115-116 | 2 | 17 |
| α-helix | 120-122 | 3 | |
| α-helix | 123-125 | 3 | |
| α-helix | 126-129 | 4 | |
Chain E: 1 helix, 6 β-strands
| Element | Residues | Length | Sheet |
|---|
| β-strand | 7-10 | 4 | 21 |
| β-strand | 18 | 1 | 21 |
| β-strand | 21-27 | 7 | 21 |
| β-strand | 37-40 | 4 | 21 |
| β-strand | 58-61 | 4 | 21 |
| α-helix | 63-65 | 3 | |
| β-strand | 66-68 | 3 | 21 |
Chain F: 12 helices, 5 β-strands
| Element | Residues | Length | Sheet |
|---|
| α-helix | 25-27 | 3 | |
| β-strand | 29-30 | 2 | 22 |
| α-helix | 31-33 | 3 | |
| α-helix | 35-42 | 8 | |
| α-helix | 44-46 | 3 | |
| α-helix | 53-61 | 9 | |
| β-strand | 65-66 | 2 | 22 |
| β-strand | 72-73 | 2 | 22 |
| β-strand | 74 | 1 | 15 |
| α-helix | 80-82 | 3 | |
| α-helix | 87-111 | 25 | |
| α-helix | 117-122 | 6 | |
| β-strand | 123 | 1 | 23 |
| α-helix | 126-134 | 9 | |
| α-helix | 136-138 | 3 | |
| α-helix | 139-149 | 11 | |
| α-helix | 156-158 | 3 | |
Chain I: 3 helices, 1 β-strand
| Element | Residues | Length | Sheet |
|---|
| α-helix | 10-16 | 7 | |
| α-helix | 17-21 | 5 | |
| α-helix | 22-34 | 13 | |
| β-strand | 37 | 1 | 9 |
Chain J: 2 helices, 1 β-strand
| Element | Residues | Length | Sheet |
|---|
| α-helix | 2-8 | 7 | |
| β-strand | 10 | 1 | 23 |
| α-helix | 11-32 | 22 | |
3 more chain groups are not listed. Open the entry in the viewer and use the sequence panel to see them.
Molecules and chains
| Molecule | Chains | Type | Length | Organism | UniProt |
|---|
| Photosystem I P700 chlorophyll a apoprotein A1 | A | protein | 755 | Thermosynechococcus vestitus BP-1 | P0A405 (AlphaFold model) |
| Photosystem I P700 chlorophyll a apoprotein A2 | B | protein | 741 | Thermosynechococcus vestitus BP-1 | P0A407 (AlphaFold model) |
| Photosystem I iron-sulfur center | C | protein | 81 | Thermosynechococcus vestitus BP-1 | P0A415 (AlphaFold model) |
| Photosystem I reaction center subunit II | D | protein | 139 | Thermosynechococcus vestitus BP-1 | P0A420 (AlphaFold model) |
| Photosystem I reaction center subunit IV | E | protein | 76 | Thermosynechococcus vestitus BP-1 | P0A423 |
| Photosystem I reaction center subunit III | F | protein | 164 | Thermosynechococcus vestitus BP-1 | P0A401 |
| Photosystem I reaction center subunit VIII | I | protein | 38 | Thermosynechococcus vestitus BP-1 | P0A427 |
| Photosystem I reaction center subunit IX | J | protein | 41 | Thermosynechococcus vestitus BP-1 | P0A429 |
| Photosystem I reaction center subunit PsaK | K | protein | 83 | Thermosynechococcus vestitus BP-1 | P0A425 |
| Photosystem I reaction center subunit XII | M | protein | 31 | Thermosynechococcus vestitus BP-1 | P0A403 |
| Photosystem I 4.8K protein | X | protein | 39 | Thermosynechococcus vestitus BP-1 | Q8DKP6 |
Sequence of entity 1 (A), FASTA
>9QFP_1 Photosystem I P700 chlorophyll a apoprotein A1 (chains A)
MTISPPEREPKVRVVVDNDPVPTSFEKWAKPGHFDRTLARGPQTTTWIWNLHALAHDFDT
HTSDLEDISRKIFSAHFGHLAVVFIWLSGMYFHGAKFSNYEAWLADPTGIKPSAQVVWPI
VGQGILNGDVGGGFHGIQITSGLFQLWRASGITNEFQLYCTAIGGLVMAGLMLFAGWFHY
HKRAPKLEWFQNVESMLNHHLAGLLGLGSLAWAGHQIHVSLPINKLLDAGVAAKDIPLPH
EFILNPSLMAELYPKVDWGFFSGVIPFFTFNWAAYSDFLTFNGGLNPVTGGLWLSDTAHH
HLAIAVLFIIAGHMYRTNWGIGHSLKEILEAHKGPFTGAGHKGLYEVLTTSWHAQLAINL
AMMGSLSIIVAQHMYAMPPYPYLATDYPTQLSLFTHHMWIGGFLVVGGAAHGAIFMVRDY
DPAMNQNNVLDRVLRHRDAIISHLNWVCIFLGFHSFGLYVHNDTMRAFGRPQDMFSDTGI
QLQPVFAQWVQNLHTLAPGGTAPNAAATASVAFGGDVVAVGGKVAMMPIVLGTADFMVHH
IHAFTIHVTVLILLKGVLFARSSRLIPDKANLGFRFPCDGPGRGGTCQVSGWDHVFLGLF
WMYNCISVVIFHFSWKMQSDVWGTVAPDGTVSHITGGNFAQSAITINGWLRDFLWAQASQ
VIGSYGSALSAYGLLFLGAHFIWAFSLMFLFSGRGYWQELIESIVWAHNKLKVAPAIQPR
ALSIIQGRAVGVAHYLLGGIATTWAFFLARIISVG
Sequence of entity 2 (B), FASTA
>9QFP_2 Photosystem I P700 chlorophyll a apoprotein A2 (chains B)
MATKFPKFSQDLAQDPTTRRIWYAIAMAHDFESHDGMTEENLYQKIFASHFGHLAIIFLW
VSGSLFHVAWQGNFEQWVQDPVNTRPIAHAIWDPQFGKAAVDAFTQAGASNPVDIAYSGV
YHWWYTIGMRTNGDLYQGAIFLLILASLALFAGWLHLQPKFRPSLSWFKNAESRLNHHLA
GLFGVSSLAWAGHLIHVAIPESRGQHVGWDNFLSTMPHPAGLAPFFTGNWGVYAQNPDTA
SHVFGTAQGAGTAILTFLGGFHPQTESLWLTDMAHHHLAIAVLFIVAGHMYRTQFGIGHS
IKEMMDAKDFFGTKVEGPFNMPHQGIYETYNNSLHFQLGWHLACLGVITSLVAQHMYSLP
PYAFIAQDHTTMAALYTHHQYIAGFLMVGAFAHGAIFLVRDYDPAQNKGNVLDRVLQHKE
AIISHLSWVSLFLGFHTLGLYVHNDVVVAFGTPEKQILIEPVFAQFIQAAHGKLLYGFDT
LLSNPDSIASTAWPNYGNVWLPGWLDAINSGTNSLFLTIGPGDFLVHHAIALGLHTTTLI
LVKGALDARGSKLMPDKKDFGYAFPCDGPGRGGTCDISAWDAFYLAMFWMLNTIGWVTFY
WHWKHLGVWEGNVAQFNESSTYLMGWLRDYLWLNSSQLINGYNPFGTNNLSVWAWMFLFG
HLVWATGFMFLISWRGYWQELIETLVWAHERTPLANLVRWKDKPVALSIVQARLVGLAHF
SVGYILTYAAFLIASTAAKFG
Sequence of entity 3 (C), FASTA
>9QFP_3 Photosystem I iron-sulfur center (chains C)
MAHTVKIYDTCIGCTQCVRACPTDVLEMVPWDGCKAGQIASSPRTEDCVGCKRCETACPT
DFLSIRVYLGAETTRSMGLAY
Sequence of entity 4 (D), FASTA
>9QFP_4 Photosystem I reaction center subunit II (chains D)
MTTLTGQPPLYGGSTGGLLSAADTEEKYAITWTSPKEQVFEMPTAGAAVMREGENLVYFA
RKEQCLALAAQQLRPRKINDYKIYRIFPDGETVLIHPKDGVFPEKVNKGREAVNSVPRSI
GQNPNPSQLKFTGKKPYDP
Sequence of entity 5 (E), FASTA
>9QFP_5 Photosystem I reaction center subunit IV (chains E)
MVQRGSKVKILRPESYWYNEVGTVASVDQTPGVKYPVIVRFDKVNYTGYSGSASGVNTNN
FALHEVQEVAPPKKGK
Sequence of entity 6 (F), FASTA
>9QFP_6 Photosystem I reaction center subunit III (chains F)
MRRFLALLLVLTLWLGFTPLASADVAGLVPCKDSPAFQKRAAAAVNTTADPASGQKRFER
YSQALCGEDGLPHLVVDGRLSRAGDFLIPSVLFLYIAGWIGWVGRAYLIAVRNSGEANEK
EIIIDVPLAIKCMLTGFAWPLAALKELASGELTAKDNEITVSPR
Sequence of entity 7 (I), FASTA
>9QFP_7 Photosystem I reaction center subunit VIII (chains I)
MMGSYAASFLPWIFIPVVCWLMPTVVMGLLFLYIEGEA
Sequence of entity 8 (J), FASTA
>9QFP_8 Photosystem I reaction center subunit IX (chains J)
MKHFLTYLSTAPVLAAIWMTITAGILIEFNRFYPDLLFHPL
Sequence of entity 9 (K), FASTA
>9QFP_9 Photosystem I reaction center subunit PsaK (chains K)
MVLATLPDTTWTPSVGLVVILCNLFAIALGRYAIQSRGKGPGLPIALPALFEGFGLPELL
ATTSFGHLLAAGVVSGLQYAGAL
Sequence of entity 10 (M), FASTA
>9QFP_10 Photosystem I reaction center subunit XII (chains M)
MALTDTQVYVALVIALLPAVLAFRLSTELYK
Sequence of entity 11 (X), FASTA
>9QFP_11 Photosystem I 4.8K protein (chains X)
MSTMATKSAKPTYAFRTFWAVLLLAINFLVAAYYFGILK
Ligands and cofactors
| ID | Name | Formula | Copies |
|---|
| LMT | Dodecyl-beta-D-maltoside | C24 H46 O11 | 16 |
| CLA | Chlorophyll a | C55 H72 Mg N4 O5 | 90 |
| PQN | Phylloquinone | C31 H46 O2 | 2 |
| CL0 | Chlorophyll a isomer | C55 H72 Mg N4 O5 | 1 |
| LMG | 1,2-distearoyl-monogalactosyl-diglyceride | C45 H86 O10 | 1 |
| MG | Magnesium ion | Mg | 1 |
| SQD | 1,2-di-O-acyl-3-O-[6-deoxy-6-sulfo-alpha-D-glucopyranosyl]-sn-glycerol | C41 H78 O12 S | 1 |
| SF4 | Iron/sulfur cluster | Fe4 S4 | 3 |
| LHG | 1,2-dipalmitoyl-phosphatidyl-glycerole | C38 H75 O10 P | 5 |
| BCR | Beta-carotene | C40 H56 | 19 |
Primary citation
Monomeric Photosystem I Cryo-EM structure at 1.8 A resolution. Boyka, J., Gaullier, G., Blikstad, C. et al. To be published.
Other PDB entries of the same protein (UniProt P0A405 (AlphaFold model), which also has an AlphaFold model), best resolution first:
- 7FIX 1.97 Å, Cryo-EM structure of cyanobacterial photosystem I in the presence of ferredoxin and…
- 1JB0 2.5 Å, Crystal Structure of Photosystem I: a Photosynthetic Reaction Center and Core Antenna…
- 7M75 2.75 Å, Room Temperature XFEL Crystallography reveals asymmetry in the vicinity of the two…
- 6TRA 2.85 Å, Cryo- EM structure of the Thermosynechococcus elongatus photosystem I in the presence of…
- 6PFY 2.9 Å, Membrane Protein Megahertz Crystallography at the European XFEL, Photosystem I at…
- 6PGK 2.9 Å, Membrane Protein Megahertz Crystallography at the European XFEL, Photosystem I XFEL at…
- 6TRC 2.98 Å, Cryo- EM structure of the Thermosynechococcus elongatus photosystem I in the presence of…
- 7M76 3.0 Å, Room Temperature XFEL Crystallography reveals asymmetry in the vicinity of the two…
- 7M78 3.0 Å, Room Temperature XFEL Crystallography reveals asymmetry in the vicinity of the two…
- 6TRD 3.16 Å, Cryo- EM structure of the Thermosynechococcus elongatus photosystem I in the presence of…
- 6LU1 3.2 Å, Cyanobacterial PSI Monomer from T. elongatus by Single Particle CRYO-EM at 3.2 A…
- 10EG 3.4 Å, Thermosynechococcus vestitus (BP-1) Photosystem I Complexed with Platinum Nanoparticles
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