EncoMPASS

Encyclopedia of Membrane Proteins Analyzed by Structure and Symmetry

National Institute of Neurological Disorders & Stroke

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Updated: August 13, 2025 9:00
7fix : EncoMPASS

7fix
General information about the complete biological unit of each membrane protein structure.

The orientation in the lipid bilayer is either taken directly from OPM or generated using the related routine PPM; the title is taken from the OPM database. However, the structure shown may be modified from the coordinate file retrievable from OPM or the PDB, because of inconsistencies with the definition of the biological unit. The coordinate file is downloadable, as is a PyMOL script for visualizing the structure.

Photosystem I, with ferredoxin and cytochrome c6

Number of Chains: 39
Number of TM Chains: 27
Amino Acids: 7137
Method: ELECTRON MICROSCOPY
Resolution: Å
Uniprot: P0A405       P0A407       P0A415       P0A420       P0A423       P0A401       P0A427       P0A429       P0A425       Q8DGB4       P0A403       P0A3C9       Q8DKP6      
Links: PDB      OPM      PDBTM 
Coordinates The structure shown may be modified from the coordinate file retrievable from OPM or from the PDB because of inconsistencies with the definition of the biological unit.

Structure Relationships
A list of chains contained in the biological unit and their relationships to other structures in the database.

Details include: (i) the predominant secondary structure (alpha or beta), (ii) the number of transmembrane regions according to our algorithm, and (iii-v) the number of neighbors according to comparisons using sequence (iii), structure (iv), or both (v).

Two chains are designated sequence neighbors when the sequence identity in the MUSCLE alignment is ≥0.85. Two chains are assigned as structural neighbors when the Fr-TM-Align structure alignment led to a TM-score of ≥0.6.

Member Class TM Domains Seq Neighbors Struct Neighbors All Neighbors Symmetry
7fix_A alpha 11 59 204 204 C3
7fix_B alpha 11 45 204 204 C3
7fix_F alpha 1 19 76 76 na
7fix_G alpha 1 20 311 311 na
7fix_H alpha 1 19 563 563 na
7fix_I alpha 2 19 82 82 na
7fix_J alpha 3 20 90 90 na
7fix_K alpha 1 20 451 451 na
7fix_M alpha 1 23 219 223 na
7fix_N alpha 11 59 204 204 C3
7fix_O alpha 11 45 204 204 C3
7fix_S alpha 1 19 76 76 na
7fix_T alpha 1 20 311 311 na
7fix_U alpha 1 19 563 563 na
7fix_V alpha 2 19 82 82 na
7fix_W alpha 3 20 90 90 na
7fix_X alpha 1 20 451 451 na
7fix_Z alpha 1 23 219 223 na
7fix_a alpha 11 59 204 204 C3
7fix_b alpha 11 45 204 204 C3
7fix_f alpha 1 19 76 76 na
7fix_g alpha 1 20 311 311 na
7fix_h alpha 1 19 563 563 na
7fix_i alpha 2 19 82 82 na
7fix_j alpha 3 20 90 90 na
7fix_k alpha 1 20 451 451 na
7fix_m alpha 1 23 219 223 na

Standard Symmetry Detection
Raw output from two symmetry detection programs: CE-Symm and SymD.

Structures were processed using CE-Symm and SymD with default options. For CE-Symm, if no symmetry was detected (reported as Order = C1), no image is provided. When symmetry is detected, different colors are used to represent the repeated elements with respect to a given symmetry axis and the PyMOL script for generating the representations is provided. [Note that CE-Symm calculations were carried out with a random seed of 3, 5, or 10, from which the result with the highest number of repeats and/or highest number of aligned residues is reported.]

For SymD, which does not report repeats information, the aligned residues (capital letters in the FASTA files) are colored blue and the accompanying PyMOL script generates this representation. [Note that SymD does not report symmetry order and so here, the order has been predicted based on the unit angle provided by the program.]

To interpret the repeat definitions, see the FAQ.

CE-Symm   2.2

Order: C3
Angle: 120.00,180.00,180.00,180.00
Translation: 0.00,0.00,0.00,0.00
RMSD: 1.69
TM-Score: 0.68
Coverage: 0.68
See additional CE-Symm data
View alignment(s)

SymD   1.6

Order: 3
Angle: 120.0
Translation: 0.0
RMSD: 0.007
TM-Score: 1.0
Coverage: 1.0
See additional SymD data
View alignment(s)

Multi-step Symmetry Detection
Consensus results from processing with SymD, CE-Symm and QuatSymm with default and customized parameters

These results were filtered using rules that take into account the restraints imposed by the membrane environment (e.g., an alpha-helical repeat should contain at least two transmembrane spans to be functionally relevant) and that consider coverage and symmetry levels. Only symmetries between repeats that are at least partially located in the membrane are considered. Note that for multi-chain complexes the order of the chains is important for symmetry detection and is therefore also reported.

Chain Order: A;a;N;B;b;O;G;g;T;H;h;U;K;k;X;M;m;Z;F;f;S;I;i;V;J;j;W;
Order: C3
Angle: 120.0
Translation: 0.0
RMSD: 0.01
TM-Score: 0.92
Coverage: 0.98
Aligned Residues: 5853
Number of Repeats: 3
Repeat Length: 2072
Levels: 1
Topology: Parallel
Angle with Membrane Normal: -89.99000000000001
Repeats:
View alignment(s)