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
1sqx : EncoMPASS

1sqx
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.

Cytochrome bc1, bovine, structure 8

Number of Chains: 22
Number of TM Chains: 12
Amino Acids: 4202
Method: X-RAY DIFFRACTION
Resolution: 2.6 Å
Uniprot: P31800       P23004       P00157       P13272       P00125       P13271       P00129       P07552       P00126       P00130      
Links: PDB      OPM      PDBTM 
MemProtMD 
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
1sqx_C alpha 8 62 246 246 C2
1sqx_D alpha 1 56 159 159 na
1sqx_E alpha 1 55 185 185 na
1sqx_F alpha 1 66 989 989 na
1sqx_I alpha 1 44 657 659 na
1sqx_K alpha 1 72 851 851 na
1sqx_N alpha 8 62 246 246 C2
1sqx_O alpha 1 56 159 159 na
1sqx_P alpha 1 55 185 185 na
1sqx_Q alpha 1 66 989 989 na
1sqx_T alpha 1 44 657 659 na
1sqx_V alpha 1 72 851 851 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: C2
Angle: 180.00
Translation: 0.00
RMSD: 0.0
TM-Score: 1.0
Coverage: 1.0
See additional CE-Symm data
View alignment(s)

SymD   1.6

Order: 2
Angle: 180.0
Translation: 0.0
RMSD: 0.001
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: C;N;D;O;E;P;F;Q;I;T;K;V;
Order: C2
Angle: 180.0
Translation: 0.0
RMSD: 0.0
TM-Score: 1.0
Coverage: 1.0
Aligned Residues: 2006
Number of Repeats: 2
Repeat Length: 1003
Levels: 1
Topology: Parallel
Angle with Membrane Normal: 0.0
Repeats:
View alignment(s)

 
v2.1.2