Structure of PDB 1k4s Chain A

Receptor sequence

>1k4sA (length=490) Species: 9606 (Homo sapiens)

QKWKWWEEERYPEGIKWKFLEHKGPVFAPPYEPLPENVKFYYDGKVMKLS
PKAEEVATFFAKMLDHEYTTKEIFRKNFFKDWRKEMTNEEKNIITNLSKC
DFTQMSQYFKAQTEARKQMSKEEKLKIKEENEKLLKEYGFCIMDNHKERI
ANFKIEPPGLFRGRGNHPKMGMLKRRIMPEDIIINCSKDAKVPSPPPGHK
WKEVRHDNKVTWLVSWTENIQGSIKYIMLNPSSRIKGEKDWQKYETARRL
KKCVDKIRNQYREDWKSKEMKVRQRAVALYFIDKLALRAGNEKEEGETAD
TVGCCSLRVEHINLHPELDGQEYVVEFDFLGKDSIRYYNKVPVEKRVFKN
LQLFMENKQPEDDLFDRLNTGILNKHLQDLMEGLTAKVFRTYNASITLQQ
QLKELTAPDENIPAKILSYNRANRAVAILCNHREENKQIALGTSKLNYLD
PRITVAWCKKWGVPIEKIYNKTQREKFAWAIDMADEDYEF

3D structure

• PDB: 1k4s The mechanism of topoisomerase I poisoning by a camptothecin analog
• Chain: A
• Resolution: 3.2 Å

Enzymatic activity

• Enzyme Commision number: 5.6.2.1: DNA topoisomerase.

Interaction with ligand

Site #	Ligand	Ligand chain	Binding residues on receptor (original residue number in PDB)	Binding residues on receptor (residue number reindexed from 1)	Binding affinity
BS01	dna	A	V410 T411 I424 Y426 M428 K436 K439 K587 N722 Y723	V210 T211 I224 Y226 M228 K236 K239 K387 N447 Y448
BS02	dna	A	H266 R364 D533 T718 Y723	H66 R164 D333 T443 Y448
BS03	dna	A	E356 P357 F361 R362 R364 H367 K374 A489 G490 N491 K493 T501 K532 D533 T585 A586 K587 R708 T747	E156 P157 F161 R162 R164 H167 K174 A289 G290 N291 K293 T301 K332 D333 T385 A386 K387 R433 T472

Gene Ontology

Molecular Function

• GO:0003677 DNA binding
• GO:0003917 DNA topoisomerase type I (single strand cut, ATP-independent) activity

Biological Process

• GO:0006265 DNA topological change

Cellular Component

• GO:0005694 chromosome

External links

• PDB: RCSB:1k4s, PDBe:1k4s, PDBj:1k4s
• PDBsum: 1k4s
• PubMed: 12426403
• UniProt: P11387|TOP1_HUMAN DNA topoisomerase 1 (Gene Name=TOP1)