7ZQC image
Entry Detail
PDB ID:
7ZQC
EMDB ID:
Keywords:
Title:
Monomeric PSI of Chlamydomonas reinhardtii at 2.31 A resolution
Biological Source:
Source Organism:
PDB Version:
Deposition Date:
2022-04-29
Release Date:
2022-11-23
Method Details:
Experimental Method:
Resolution:
2.31 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Chlorophyll a-b binding protein, chloroplastic
Chain IDs:L (auth: 1), P (auth: Z)
Chain Length:228
Number of Molecules:2
Biological Source:Chlamydomonas reinhardtii
Polymer Type:polypeptide(L)
Description:Chlorophyll a-b binding protein, chloroplastic
Chain IDs:M (auth: 3)
Chain Length:298
Number of Molecules:1
Biological Source:Chlamydomonas reinhardtii
Polymer Type:polypeptide(L)
Description:Chlorophyll a-b binding protein, chloroplastic (Lhca4)
Chain IDs:Q (auth: 4)
Chain Length:264
Number of Molecules:1
Biological Source:Chlamydomonas reinhardtii
Polymer Type:polypeptide(L)
Description:Chlorophyll a-b binding protein, chloroplastic
Chain IDs:R (auth: 5)
Chain Length:257
Number of Molecules:1
Biological Source:Chlamydomonas reinhardtii
Polymer Type:polypeptide(L)
Description:Chlorophyll a-b binding protein, chloroplastic
Chain IDs:S (auth: 6)
Chain Length:257
Number of Molecules:1
Biological Source:Chlamydomonas reinhardtii
Polymer Type:polypeptide(L)
Description:Chlorophyll a-b binding protein, chloroplastic
Chain IDs:N (auth: 7)
Chain Length:241
Number of Molecules:1
Biological Source:Chlamydomonas reinhardtii
Polymer Type:polypeptide(L)
Description:Chlorophyll a-b binding protein, chloroplastic
Chain IDs:O (auth: 8)
Chain Length:243
Number of Molecules:1
Biological Source:Chlamydomonas reinhardtii
Polymer Type:polypeptide(L)
Description:Chlorophyll a-b binding protein, chloroplastic
Chain IDs:T (auth: 9)
Chain Length:213
Number of Molecules:1
Biological Source:Chlamydomonas reinhardtii
Polymer Type:polypeptide(L)
Description:Photosystem I P700 chlorophyll a apoprotein A1
Chain IDs:A
Chain Length:751
Number of Molecules:1
Biological Source:Chlamydomonas reinhardtii
Polymer Type:polypeptide(L)
Description:Photosystem I P700 chlorophyll a apoprotein A2
Chain IDs:B
Chain Length:735
Number of Molecules:1
Biological Source:Chlamydomonas reinhardtii
Polymer Type:polypeptide(L)
Description:Photosystem I iron-sulfur center
Chain IDs:C
Chain Length:81
Number of Molecules:1
Biological Source:Chlamydomonas reinhardtii
Polymer Type:polypeptide(L)
Description:Photosystem I reaction center subunit II, chloroplastic
Chain IDs:D
Chain Length:196
Number of Molecules:1
Biological Source:Chlamydomonas reinhardtii
Polymer Type:polypeptide(L)
Description:Photosystem I reaction center subunit IV, chloroplastic
Chain IDs:E
Chain Length:97
Number of Molecules:1
Biological Source:Chlamydomonas reinhardtii
Polymer Type:polypeptide(L)
Description:Photosystem I reaction center subunit III, chloroplastic
Chain IDs:F
Chain Length:227
Number of Molecules:1
Biological Source:Chlamydomonas reinhardtii
Polymer Type:polypeptide(L)
Description:Photosystem I reaction center subunit V, chloroplastic
Chain IDs:G
Chain Length:126
Number of Molecules:1
Biological Source:Chlamydomonas reinhardtii
Polymer Type:polypeptide(L)
Description:Photosystem I reaction center subunit VIII
Chain IDs:H (auth: I)
Chain Length:106
Number of Molecules:1
Biological Source:Chlamydomonas reinhardtii
Polymer Type:polypeptide(L)
Description:Photosystem I reaction center subunit IX
Chain IDs:I (auth: J)
Chain Length:40
Number of Molecules:1
Biological Source:Chlamydomonas reinhardtii
Polymer Type:polypeptide(L)
Description:Photosystem I reaction center subunit psaK, chloroplastic
Chain IDs:K
Chain Length:113
Number of Molecules:1
Biological Source:Chlamydomonas reinhardtii
Polymer Type:polypeptide(L)
Description:PSI subunit V
Chain IDs:J (auth: L)
Chain Length:196
Number of Molecules:1
Biological Source:Chlamydomonas reinhardtii
Modified Residue
Compound ID Chain ID Parent Comp ID Details 2D Image
AME I MET modified residue
Primary Citation
Algal photosystem I dimer and high-resolution model of PSI-plastocyanin complex.
Nat.Plants 8 1191 1201 (2022)
PMID: 36229605 DOI: 10.1038/s41477-022-01253-4

Abstact

Photosystem I (PSI) enables photo-electron transfer and regulates photosynthesis in the bioenergetic membranes of cyanobacteria and chloroplasts. Being a multi-subunit complex, its macromolecular organization affects the dynamics of photosynthetic membranes. Here we reveal a chloroplast PSI from the green alga Chlamydomonas reinhardtii that is organized as a homodimer, comprising 40 protein subunits with 118 transmembrane helices that provide scaffold for 568 pigments. Cryogenic electron microscopy identified that the absence of PsaH and Lhca2 gives rise to a head-to-head relative orientation of the PSI-light-harvesting complex I monomers in a way that is essentially different from the oligomer formation in cyanobacteria. The light-harvesting protein Lhca9 is the key element for mediating this dimerization. The interface between the monomers is lacking PsaH and thus partially overlaps with the surface area that would bind one of the light-harvesting complex II complexes in state transitions. We also define the most accurate available PSI-light-harvesting complex I model at 2.3 Å resolution, including a flexibly bound electron donor plastocyanin, and assign correct identities and orientations to all the pigments, as well as 621 water molecules that affect energy transfer pathways.

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