← Back to search
1k4s

HUMAN DNA TOPOISOMERASE I IN COVALENT COMPLEX WITH A 22 BASE PAIR DNA DUPLEX

Method: X-RAY DIFFRACTION
▼

1. Protein Identity and Related Structures Protein Identity & Related Structures

DNA topoisomerase I

Homo sapiens

UniProt P11387

State in the Current Structure

Assembly Physical composition Protein state Molecular copy count Associated components Data consistency
1 Protein–DNA Monomer Protein 1 DNA 3 5'-D(*AP*AP*AP*AP*AP*GP*AP*CP*(5IU)P*(5IU))-3' × 1 5'-D(*(SPT)P*GP*AP*AP*AP*AP*AP*(5IU)P*(5IU)P*(5IU)P*(5IU)P*T)-3' × 1 5'-D(*AP*AP*AP*AP*AP*TP*(IDO)UP*(IDO)UP*(IDO)UP*(IDO)UP*CP*AP*AP*AP*GP*(IDO)UP*CP*(IDO)UP*(IDO)UP*(IDO)UP*(IDO)UP*T)-3' × 1 Consistent with all polymers

Other States of the Same Protein in the Database

Monomer

None

Homodimer

None

Homotetramer

None

Other homooligomers

None

Heteromeric or nucleic-acid complex
1a35 1a36 1ej9 1k4s 1k4t 1lpq 1nh3 1r49 1rr8 1rrj 1sc7 1seu

14 assemblies; showing the first 12

View Construct and Data Evidence
UniProt name TOP1_HUMAN
Isoform —
PDB entities 4
Chains and sequence ranges Author chain A； PDBConstruct 1–592； UniProt 174–765

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.

▼

2. Structure Basics 2. Structure Basics

Entry ID entry_id1k4s
Deposition date deposition_date2001-10-08
Structure title titleHUMAN DNA TOPOISOMERASE I IN COVALENT COMPLEX WITH A 22 BASE PAIR DNA DUPLEX
Keywords keywordsComplex (ISOMERASE-DNA), DNA, Topoisomerase I, ISOMERASE-DNA complex; ISOMERASE/DNA
Experimental Method methodX-RAY DIFFRACTION
▼

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.

1k4s__assembly_1__model_1

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

Download this curve (.dat)

1k4s__assembly_1__model_1 | I(q)

10-2 10-1 106 107 108 q (1/Angstrom) I(q)
100 plotted points; both axes use logarithmic scales.

1k4s__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）26.34 Å
Rg (electron density)26.11 Å
Total Rg26.59 Å
Atom count4858
Residues517
Excluded volume83851 ų
Maximum q0.500 Å⁻¹
Assembly Model Structure unit Oligomeric description Status CRYSOL Actions
1 1 1k4s__assembly_1__model_1 tetrameric （4） Success 4.1.3-1-20251215 (887e7ef) View Download
▶

4. Crystallography and Experiment 4. Crystallography & Experiment

▶

5. Entities and Polymers Entities & Polymers (4)

▼

6. Fold Classification (SCOP + CATH) 6 domains

SCOP 2.08 (2 domains)

Domain ID domain_idd1k4sa1
Class classd — Alpha and beta proteins (a+b)
Fold Fold foldd.163 — DNA breaking-rejoining enzymes
Superfamily Superfamily superfamilyd.163.1 — DNA breaking-rejoining enzymes
Family Family familyd.163.1.2 — Eukaryotic DNA topoisomerase I, catalytic core
Domain ID domain_idd1k4sa2
Class classe — Multi-domain proteins (alpha and beta)
Fold Fold folde.15 — Eukaryotic DNA topoisomerase I, N-terminal DNA-binding fragment
Superfamily Superfamily superfamilye.15.1 — Eukaryotic DNA topoisomerase I, N-terminal DNA-binding fragment
Family Family familye.15.1.1 — Eukaryotic DNA topoisomerase I, N-terminal DNA-binding fragment

CATH v4.4 (4 domains)

Domain ID domain_id1k4sA01
Class class2 — Mainly Beta
Architecture architecture170 — Beta Complex
Topology topology11 — DNA Topoisomerase I; domain 2
Homologous superfamily homologous superfamily10 — DNA Topoisomerase I, domain 2
Domain ID domain_id1k4sA02
Class class1 — Mainly Alpha
Architecture architecture10 — Orthogonal Bundle
Topology topology10 — Arc Repressor Mutant, subunit A
Homologous superfamily homologous superfamily41 — Yeast DNA topoisomerase - domain 1
Domain ID domain_id1k4sA03
Class class3 — Alpha Beta
Architecture architecture90 — Alpha-Beta Complex
Topology topology15 — Topoisomerase I; Chain A, domain 3
Homologous superfamily homologous superfamily10 — Topoisomerase I; Chain A, domain 3
Domain ID domain_id1k4sA04
Class class1 — Mainly Alpha
Architecture architecture10 — Orthogonal Bundle
Topology topology132 — Topoisomerase I; Chain A, domain 4
Homologous superfamily homologous superfamily10 —
▶

7. Citations (1)