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1qc9

THE CRYSTALLOGRAPHIC STRUCTURE OF RESTRICTION ENDONUCLEASE ECO RI AT 3.3 A IN THE ABSENSE OF DNA

Method: X-RAY DIFFRACTION
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1. Protein Identity and Related Structures Protein Identity & Related Structures

PROTEIN (ECO RI ENDONUCLEASE)

OrganismNot specified

UniProt P00642

State in the Current Structure

Assembly Physical composition Protein state Molecular copy count Associated components Data consistency
1 Protein homooligomer Homooligomer Protein 2 No other associated polymer Consistent with protein count
2 Protein homooligomer Homooligomer Protein 2 No other associated polymer Consistent with protein count

Other States of the Same Protein in the Database

Monomer

None

Homodimer
1qc9 1qc9

2 assemblies

Homotetramer

None

Other homooligomers

None

Heteromeric or nucleic-acid complex
1ckq 1cl8 1eri 1qps 1qrh 1qri 2oxv

7 assemblies

View Construct and Data Evidence
UniProt name T2E1_ECOLI
Isoform —
PDB entities 1
Chains and sequence ranges Author chain A； PDBConstruct 1–276； UniProt 2–277 Author chain B； PDBConstruct 1–276； UniProt 2–277 Author chain C； PDBConstruct 1–276； UniProt 2–277

The page prioritizes protein identity, the current assembly, associated components, oligomeric state and cross-PDB links. Chain mapping and sequence ranges are retained as data evidence. Internal IDs, import timestamps and assembly operation expressions are maintenance fields and are not shown here.

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2. Structure Basics 2. Structure Basics

Entry ID entry_id1qc9
Deposition date deposition_date1999-05-18
Structure title titleTHE CRYSTALLOGRAPHIC STRUCTURE OF RESTRICTION ENDONUCLEASE ECO RI AT 3.3 A IN THE ABSENSE OF DNA
Keywords keywordsPROTEIN, RESTRICTION ENDONUCLEASE, APOENZYME, ENDONUCLEASE; ENDONUCLEASE
Experimental Method methodX-RAY DIFFRACTION
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3. Official assembly/model SAXS Official SAXS Profiles

This page reads only the latest assembly calculations. Every curve maps to an explicit PDB entry, official biological assembly and coordinate model.

1qc9__assembly_1__model_1

Assembly 1 · Model 1 · CRYSOL 4.1.3-1-20251215 (887e7ef)

Download this curve (.dat)

1qc9__assembly_1__model_1 | I(q)

10-2 10-1 106 107 q (1/Angstrom) I(q)
100 plotted points; both axes use logarithmic scales.

1qc9__assembly_1__model_1 | P(r) · Pending

The new assembly/model P(r) has not been calculated yet This placeholder does not display legacy data r (Angstrom) P(r)
P(r) will be calculated and displayed separately for the same assembly/model.
Rg（Guinier）25.69 Å
Rg (electron density)24.70 Å
Total Rg25.53 Å
Atom count3986
Residues506
Excluded volume70926 ų
Maximum q0.500 Å⁻¹
Assembly Model Structure unit Oligomeric description Status CRYSOL Actions
1 1 1qc9__assembly_1__model_1 dimeric （2） Success 4.1.3-1-20251215 (887e7ef) View Download
2 1 1qc9__assembly_2__model_1 dimeric （2） Success 4.1.3-1-20251215 (887e7ef) View Download
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4. Crystallography and Experiment 4. Crystallography & Experiment

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5. Entities and Polymers Entities & Polymers (1)

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6. Fold Classification (SCOP + CATH) 6 domains

SCOP 2.08 (3 domains)

Domain ID domain_idd1qc9a_
Class classc — Alpha and beta proteins (a/b)
Fold Fold foldc.52 — Restriction endonuclease-like
Superfamily Superfamily superfamilyc.52.1 — Restriction endonuclease-like
Family Family familyc.52.1.1 — Restriction endonuclease EcoRI
Domain ID domain_idd1qc9b_
Class classc — Alpha and beta proteins (a/b)
Fold Fold foldc.52 — Restriction endonuclease-like
Superfamily Superfamily superfamilyc.52.1 — Restriction endonuclease-like
Family Family familyc.52.1.1 — Restriction endonuclease EcoRI
Domain ID domain_idd1qc9c_
Class classc — Alpha and beta proteins (a/b)
Fold Fold foldc.52 — Restriction endonuclease-like
Superfamily Superfamily superfamilyc.52.1 — Restriction endonuclease-like
Family Family familyc.52.1.1 — Restriction endonuclease EcoRI

CATH v4.4 (3 domains)

Domain ID domain_id1qc9A00
Class class3 — Alpha Beta
Architecture architecture40 — 3-Layer(aba) Sandwich
Topology topology580 — ECO RI Endonuclease; Chain A
Homologous superfamily homologous superfamily10 — Eco RI Endonuclease, subunit A
Domain ID domain_id1qc9B00
Class class3 — Alpha Beta
Architecture architecture40 — 3-Layer(aba) Sandwich
Topology topology580 — ECO RI Endonuclease; Chain A
Homologous superfamily homologous superfamily10 — Eco RI Endonuclease, subunit A
Domain ID domain_id1qc9C00
Class class3 — Alpha Beta
Architecture architecture40 — 3-Layer(aba) Sandwich
Topology topology580 — ECO RI Endonuclease; Chain A
Homologous superfamily homologous superfamily10 — Eco RI Endonuclease, subunit A
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7. Citations (1)