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Protein Structures and Oligomeric States

Enter a protein name, UniProt accession or PDB ID. Name searches ask you to confirm the protein identity before related structures are queried.

Current Protein Identity：Q13309 New Search
26PDB entries
39Biological assembly
41chain/assembly records
Main Difference Dimensions in This Set
Different construct Different mutation/modification Different assembly state Different ligand/ion Different experimental method Different experimental conditions Different structure-quality metrics

Difference tags compare only the current result set; every original PDB and assembly record remains separate.

Related-Structure Differences

Each row represents one biological assembly in one PDB entry; multiple monomers of the same protein are listed separately.

PDB Entry Assembly / Oligomeric State Construct Mutations and Modifications Ligands, Ions and Non-polymers Experimental Method Experimental Conditions Structure Quality
1FQV Insights into scf ubiquitin ligases from the structure of the skp1-skp2 complex Deposited 2000-09-06 Assembly 1 Protein heterocomplex Heteromer；Protein × 2 PDB declaration: dimeric（2） Consistent with protein count
Chain A 89–424（336 aa） Fragment：101-436
Not recorded No recorded non-water small molecule X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 8.5；277 K；PEG 4000, Tris-Cl, ammonium acetate, DTT, pH 8.5, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.80 Å R-free 0.314
1FQV Insights into scf ubiquitin ligases from the structure of the skp1-skp2 complex Deposited 2000-09-06 Assembly 2 Protein heterocomplex Heteromer；Protein × 2 PDB declaration: dimeric（2） Consistent with protein count
Chain C 89–424（336 aa） Fragment：101-436
Not recorded No recorded non-water small molecule X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 8.5；277 K；PEG 4000, Tris-Cl, ammonium acetate, DTT, pH 8.5, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.80 Å R-free 0.314
1FQV Insights into scf ubiquitin ligases from the structure of the skp1-skp2 complex Deposited 2000-09-06 Assembly 3 Protein heterocomplex Heteromer；Protein × 2 PDB declaration: dimeric（2） Consistent with protein count
Chain E 89–424（336 aa） Fragment：101-436
Not recorded No recorded non-water small molecule X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 8.5；277 K；PEG 4000, Tris-Cl, ammonium acetate, DTT, pH 8.5, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.80 Å R-free 0.314
1FQV Insights into scf ubiquitin ligases from the structure of the skp1-skp2 complex Deposited 2000-09-06 Assembly 4 Protein heterocomplex Heteromer；Protein × 2 PDB declaration: dimeric（2） Consistent with protein count
Chain G 89–424（336 aa） Fragment：101-436
Not recorded No recorded non-water small molecule X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 8.5；277 K；PEG 4000, Tris-Cl, ammonium acetate, DTT, pH 8.5, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.80 Å R-free 0.314
1FQV Insights into scf ubiquitin ligases from the structure of the skp1-skp2 complex Deposited 2000-09-06 Assembly 5 Protein heterocomplex Heteromer；Protein × 2 PDB declaration: dimeric（2） Consistent with protein count
Chain I 89–424（336 aa） Fragment：101-436
Not recorded No recorded non-water small molecule X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 8.5；277 K；PEG 4000, Tris-Cl, ammonium acetate, DTT, pH 8.5, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.80 Å R-free 0.314
1FQV Insights into scf ubiquitin ligases from the structure of the skp1-skp2 complex Deposited 2000-09-06 Assembly 6 Protein heterocomplex Heteromer；Protein × 2 PDB declaration: dimeric（2） Consistent with protein count
Chain K 89–424（336 aa） Fragment：101-436
Not recorded No recorded non-water small molecule X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 8.5；277 K；PEG 4000, Tris-Cl, ammonium acetate, DTT, pH 8.5, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.80 Å R-free 0.314
1FQV Insights into scf ubiquitin ligases from the structure of the skp1-skp2 complex Deposited 2000-09-06 Assembly 7 Protein heterocomplex Heteromer；Protein × 2 PDB declaration: dimeric（2） Consistent with protein count
Chain M 89–424（336 aa） Fragment：101-436
Not recorded No recorded non-water small molecule X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 8.5；277 K；PEG 4000, Tris-Cl, ammonium acetate, DTT, pH 8.5, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.80 Å R-free 0.314
1FQV Insights into scf ubiquitin ligases from the structure of the skp1-skp2 complex Deposited 2000-09-06 Assembly 8 Protein heterocomplex Heteromer；Protein × 2 PDB declaration: dimeric（2） Consistent with protein count
Chain O 89–424（336 aa） Fragment：101-436
Not recorded No recorded non-water small molecule X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 8.5；277 K；PEG 4000, Tris-Cl, ammonium acetate, DTT, pH 8.5, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.80 Å R-free 0.314
1FS1 INSIGHTS INTO SCF UBIQUITIN LIGASES FROM THE STRUCTURE OF THE SKP1-SKP2 COMPLEX Deposited 2000-09-08 Assembly 1 Protein heterocomplex Heteromer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain A 101–153（53 aa） Fragment：RESIDUES 101-153
Chain C 101–153（53 aa） Fragment：RESIDUES 101-153
Not recorded No recorded non-water small molecule X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 4.6；277 K；PEG 1500, sodium acetate, ammonium acetate, DTT, pH 4.6, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 1.80 Å R-free 0.274
1FS2 INSIGHTS INTO SCF UBIQUITIN LIGASES FROM THE STRUCTURE OF THE SKP1-SKP2 COMPLEX Deposited 2000-09-08 Assembly 1 Protein heterocomplex Heteromer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain A 89–398（310 aa） Fragment：RESIDUES 101-153; 193-410 (F-BOX + 8 LRRS)
Chain C 89–398（310 aa） Fragment：RESIDUES 101-153; 193-410 (F-BOX + 8 LRRS)
Not recorded No recorded non-water small molecule X-RAY DIFFRACTION mmCIF provides none of the parsed conditions Resolution 2.90 Å R-free 0.287
1LDK Structure of the Cul1-Rbx1-Skp1-F boxSkp2 SCF Ubiquitin Ligase Complex Deposited 2002-04-08 Assembly 1 Protein heterocomplex Heteromer；Protein × 5 PDB declaration: pentameric（5） Consistent with protein count
Chain E 97–137（41 aa）
Not recorded ZN ZINC ION × 3 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 7；277 K；peg4k, pH 7.0, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 3.10 Å R-free 0.331
1LDK Structure of the Cul1-Rbx1-Skp1-F boxSkp2 SCF Ubiquitin Ligase Complex Deposited 2002-04-08 Assembly 2 Protein heterocomplex Heteromer；Protein × 10 PDB declaration: decameric（10） Consistent with protein count
Chain E 97–137（41 aa）
Not recorded ZN ZINC ION × 6 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 7；277 K；peg4k, pH 7.0, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 3.10 Å R-free 0.331
2ASS Crystal structure of the Skp1-Skp2-Cks1 complex Deposited 2005-08-24 Assembly 1 Protein heterocomplex Heteromer；Protein × 3 PDB declaration: trimeric（3） Consistent with protein count
Chain B 89–424（336 aa）
Not recorded PO4 PHOSPHATE ION × 3 BEN BENZAMIDINE × 2 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 7.6；277 K；BTP, sodium/potassium phosphate, benzamidine, pH 7.6, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 3.00 Å R-free 0.242
2ASS Crystal structure of the Skp1-Skp2-Cks1 complex Deposited 2005-08-24 Assembly 2 Protein heterocomplex Heteromer；Protein × 6 PDB declaration: hexameric（6） Consistent with protein count
Chain B 89–424（336 aa）
Not recorded PO4 PHOSPHATE ION × 6 BEN BENZAMIDINE × 4 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 7.6；277 K；BTP, sodium/potassium phosphate, benzamidine, pH 7.6, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 3.00 Å R-free 0.242
2ASS Crystal structure of the Skp1-Skp2-Cks1 complex Deposited 2005-08-24 Assembly 3 Protein heterocomplex Heteromer；Protein × 6 PDB declaration: hexameric（6） Consistent with protein count
Chain B 89–424（336 aa）
Not recorded PO4 PHOSPHATE ION × 6 BEN BENZAMIDINE × 4 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 7.6；277 K；BTP, sodium/potassium phosphate, benzamidine, pH 7.6, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 3.00 Å R-free 0.242
2AST Crystal structure of Skp1-Skp2-Cks1 in complex with a p27 peptide Deposited 2005-08-24 Assembly 1 Protein heterocomplex Heteromer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain B 89–424（336 aa）
Not recorded BEN BENZAMIDINE × 2 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 8.5；277 K；PEG8K, 5% benzamidine, pH 8.5, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.30 Å R-free 0.221
2AST Crystal structure of Skp1-Skp2-Cks1 in complex with a p27 peptide Deposited 2005-08-24 Assembly 2 Protein heterocomplex Heteromer；Protein × 8 PDB declaration: octameric（8） Consistent with protein count
Chain B 89–424（336 aa）
Not recorded BEN BENZAMIDINE × 4 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 8.5；277 K；PEG8K, 5% benzamidine, pH 8.5, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.30 Å R-free 0.221
2AST Crystal structure of Skp1-Skp2-Cks1 in complex with a p27 peptide Deposited 2005-08-24 Assembly 3 Protein heterocomplex Heteromer；Protein × 8 PDB declaration: octameric（8） Consistent with protein count
Chain B 89–424（336 aa）
Not recorded BEN BENZAMIDINE × 4 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 8.5；277 K；PEG8K, 5% benzamidine, pH 8.5, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.30 Å R-free 0.221
7B5L Ubiquitin ligation to F-box protein substrates by SCF-RBR E3-E3 super-assembly: NEDD8-CUL1-RBX1-SKP1-SKP2-CKSHS1-Cyclin A-CDK2-p27-UBE2L3~Ub~ARIH1. Transition State 1 Deposited 2020-12-04 Assembly 1 Protein heterocomplex Heteromer；Protein × 12 PDB declaration: dodecameric（12） Consistent with protein count
Chain T 1–424（424 aa）
Not recorded ZN ZINC ION × 9 SY8 5-azanylpentan-2-one × 1 ELECTRON MICROSCOPY
cryo-EM buffer pH 7.8
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.80 Å
7B5M Ubiquitin ligation to F-box protein substrates by SCF-RBR E3-E3 super-assembly: CUL1-RBX1-SKP1-SKP2-CKSHS1-p27~Ub~ARIH1. Transition State 2 Deposited 2020-12-05 Assembly 1 Protein heterocomplex Heteromer；Protein × 8 PDB declaration: octameric（8） Consistent with protein count
Chain T 1–424（424 aa）
Not recorded ZN ZINC ION × 5 ELECTRON MICROSCOPY
cryo-EM buffer pH 7.8
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.91 Å
7B5R Ubiquitin ligation to F-box protein substrates by SCF-RBR E3-E3 super-assembly: CUL1-RBX1-SKP1-SKP2-CKSHS1-Cyclin A-CDK2-p27 Deposited 2020-12-07 Assembly 1 Protein heterocomplex Heteromer；Protein × 7 PDB declaration: heptameric（7） Consistent with protein count
Chain T 1–424（424 aa）
Not recorded No recorded non-water small molecule ELECTRON MICROSCOPY
cryo-EM buffer pH 7.8
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.80 Å
7LUO N-terminus of Skp2 bound to Cyclin A Deposited 2021-02-22 Assembly 1 Insufficient information Heteromer；Protein × 8 PDB declaration: octameric（8） Consistent with protein count
Chain A 17–83（67 aa）
Not recorded No recorded non-water small molecule X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；pH 6.2；293 K；1.7 M Sodium-potassium phosphate
Resolution 3.17 Å R-free 0.277
7LUO N-terminus of Skp2 bound to Cyclin A Deposited 2021-02-22 Assembly 2 Insufficient information Heteromer；Protein × 8 PDB declaration: octameric（8） Consistent with protein count
Chain C 17–83（67 aa）
Not recorded No recorded non-water small molecule X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；pH 6.2；293 K；1.7 M Sodium-potassium phosphate
Resolution 3.17 Å R-free 0.277
7Z8T CAND1-SCF-SKP2 CAND1 engaged SCF rocked Deposited 2022-03-18 Assembly 1 Protein heterocomplex Heteromer；Protein × 5 PDB declaration: pentameric（5） Consistent with protein count
Chain F 1–424（424 aa）
Not recorded ZN ZINC ION × 3 ELECTRON MICROSCOPY
cryo-EM buffer pH 7.5
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.00 Å
7Z8V CAND1-SCF-SKP2 (SKP1deldel) CAND1 engaged SCF rocked Deposited 2022-03-18 Assembly 1 Protein heterocomplex Heteromer；Protein × 5 PDB declaration: pentameric（5） Consistent with protein count
Chain F 1–424（424 aa）
Not recorded ZN ZINC ION × 3 ELECTRON MICROSCOPY
cryo-EM buffer pH 7.5
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 2.70 Å
7ZBW CAND1-SCF-SKP2 CAND1 rolling-2 SCF engaged Deposited 2022-03-24 Assembly 1 Protein heterocomplex Heteromer；Protein × 5 PDB declaration: pentameric（5） Consistent with protein count
Chain F 1–424（424 aa）
Not recorded No recorded non-water small molecule ELECTRON MICROSCOPY
cryo-EM buffer pH 7.5
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.50 Å
7ZBZ CAND1 delhairpin-SCF-SKP2 CAND1 partly engaged SCF partly rocked Deposited 2022-03-24 Assembly 1 Protein heterocomplex Heteromer；Protein × 5 PDB declaration: pentameric（5） Consistent with protein count
Chain F 1–424（424 aa）
Not recorded ZN ZINC ION × 3 ELECTRON MICROSCOPY
cryo-EM buffer pH 7.5
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.10 Å
8BYA Cryo-EM structure of SKP1-SKP2-CKS1-CDK2-CyclinA-p27KIP1 Complex Deposited 2022-12-12 Assembly 1 Protein heterocomplex Heteromer；Protein × 7 PDB declaration: heptameric（7） Consistent with protein count
Chain E 1–424（424 aa）
Not recorded No recorded non-water small molecule ELECTRON MICROSCOPY
cryo-EM buffer pH 7.8
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.38 Å
8BYL Cryo-EM structure of SKP1-SKP2-CKS1 from the SCFSKP2 E3 ligase complex Deposited 2022-12-13 Assembly 1 Protein heterocomplex Heteromer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain B 1–424（424 aa）
Not recorded No recorded non-water small molecule ELECTRON MICROSCOPY
cryo-EM buffer pH 7.8
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.50 Å
8CDJ CAND1 b-hairpin++-SCF-SKP2 CAND1 rolling SCF engaged Deposited 2023-01-31 Assembly 1 Protein heterocomplex Heteromer；Protein × 5 PDB declaration: pentameric（5） Consistent with protein count
Chain F 1–424（424 aa）
Not recorded No recorded non-water small molecule ELECTRON MICROSCOPY
cryo-EM buffer pH 7.5
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.40 Å
8CDK CAND1 b-hairpin++-SCF-SKP2 CAND1 partly engaged SCF partly rocked Deposited 2023-01-31 Assembly 1 Protein heterocomplex Heteromer；Protein × 5 PDB declaration: pentameric（5） Consistent with protein count
Chain F 1–424（424 aa）
Not recorded ZN ZINC ION × 3 ELECTRON MICROSCOPY
cryo-EM buffer pH 7.5
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.32 Å
8OR0 CAND1-CUL1-RBX1-SKP1-SKP2-CKS1-CDK2 Deposited 2023-04-12 Assembly 1 Protein heterocomplex Heteromer；Protein × 7 PDB declaration: heptameric（7） Consistent with protein count
Chain E 1–424（424 aa）
Not recorded ZN ZINC ION × 3 ELECTRON MICROSCOPY
cryo-EM buffer pH 7.5
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.10 Å
8OR3 CAND1-CUL1-RBX1-SKP1-SKP2-DCNL1 Deposited 2023-04-13 Assembly 1 Protein heterocomplex Heteromer；Protein × 6 PDB declaration: hexameric（6） Consistent with protein count
Chain E 1–424（424 aa）
Not recorded ZN ZINC ION × 3 ELECTRON MICROSCOPY
cryo-EM buffer pH 7.5
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 2.90 Å
8OR4 Partially dissociated CAND1-CUL1-RBX1-SKP1-SKP2-CKS1-CDK2 Deposited 2023-04-13 Assembly 1 Protein heterocomplex Heteromer；Protein × 7 PDB declaration: heptameric（7） Consistent with protein count
Chain E 1–424（424 aa）
Not recorded No recorded non-water small molecule ELECTRON MICROSCOPY
cryo-EM buffer pH 7.5
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.80 Å
9QO0 Pre-activated 9-subunit COP9 signalosome and neddylated SCF (Skp1-Skp2-Cks1) complex structure Deposited 2025-03-25 Assembly 1 Protein heterocomplex Heteromer；Protein × 15 PDB declaration: 15-meric（15） Consistent with protein count
Chain M 1–424（424 aa）
Not recorded IHP INOSITOL HEXAKISPHOSPHATE × 1 ZN ZINC ION × 3 ELECTRON MICROSCOPY
cryo-EM buffer pH 7.5；15 mM Hepes pH 7.5, 120 mM NaCl, 0.5 mM DTT
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.26 Å
9QO2 Dissociation-state-1 of 9-subunit CSN and SCF (SKP1-SKP2-CKS1) complex Deposited 2025-03-25 Assembly 1 Protein heterocomplex Heteromer；Protein × 14 PDB declaration: 14-meric（14） Consistent with protein count
Chain M 1–424（424 aa）
Not recorded IHP INOSITOL HEXAKISPHOSPHATE × 1 ZN ZINC ION × 3 ELECTRON MICROSCOPY
cryo-EM buffer pH 7.5；15 mM Hepes pH 7.5, 120 mM NaCl, 0.5 mM DTT
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.80 Å
9QO3 Dissociation-state-2 of 9-subunit CSN and SCF (SKP1-SKP2-CKS1) complex Deposited 2025-03-25 Assembly 1 Protein heterocomplex Heteromer；Protein × 13 PDB declaration: 13-meric（13） Consistent with protein count
Chain M 1–424（424 aa）
Not recorded ZN ZINC ION × 1 IHP INOSITOL HEXAKISPHOSPHATE × 1 ELECTRON MICROSCOPY
cryo-EM buffer pH 7.5；15 mM Hepes pH 7.5, 120 mM NaCl, 0.5 mM DTT
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 4.60 Å
9QO4 Dissociation-state-3 of 9-subunit CSN and SCF (SKP1-SKP2-CKS1) complex Deposited 2025-03-25 Assembly 1 Protein heterocomplex Heteromer；Protein × 14 PDB declaration: 14-meric（14） Consistent with protein count
Chain M 1–424（424 aa）
Not recorded IHP INOSITOL HEXAKISPHOSPHATE × 1 ZN ZINC ION × 4 ELECTRON MICROSCOPY
cryo-EM buffer pH 7.5；15 mM Hepes pH 7.5, 120 mM NaCl, 0.5 mM DTT
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 2.95 Å
9QO5 Dissociation-state-4 of 9-subunit CSN and SCF (SKP1-SKP2-CKS1) complex Deposited 2025-03-25 Assembly 1 Protein heterocomplex Heteromer；Protein × 14 PDB declaration: 14-meric（14） Consistent with protein count
Chain M 1–424（424 aa）
Not recorded IHP INOSITOL HEXAKISPHOSPHATE × 1 ZN ZINC ION × 1 ELECTRON MICROSCOPY
cryo-EM buffer pH 7.5；15 mM Hepes pH 7.5, 120 mM NaCl, 0.5 mM DTT
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 4.00 Å

This page presents structural evidence recorded in PDB/mmCIF.“No recorded non-water small molecule” does not prove that the experimental sample was ligand-free; experimental conditions belong to the PDB experiment, while ligands and copy counts are shown for each biological assembly.