1TL8

Human DNA topoisomerase I (70 kDa) in complex with the indenoisoquinoline AI-III-52 and covalent complex with a 22 base pair DNA duplex


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.1 Å
  • R-Value Free: 0.305 
  • R-Value Work: 0.229 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Synthesis and Mechanism of Action Studies of a Series of Norindenoisoquinoline Topoisomerase I Poisons Reveal an Inhibitor with a Flipped Orientation in the Ternary DNA-Enzyme-Inhibitor Complex As Determined by X-ray Crystallographic Analysis

Ioanoviciu, A.Antony, S.Pommier, Y.Staker, B.L.Stewart, L.Cushman, M.

(2005) J.Med.Chem. 48: 4803-4814

  • DOI: 10.1021/jm050076b

  • PubMed Abstract: 
  • Several norindenoisoquinolines substituted with methoxy or methylenedioxy groups have been prepared and their anticancer properties evaluated in cancer cell cultures and in topoisomerase I inhibition assays. 2,3-Dimethoxy-8,9-methylenedioxy-11H-inden ...

    Several norindenoisoquinolines substituted with methoxy or methylenedioxy groups have been prepared and their anticancer properties evaluated in cancer cell cultures and in topoisomerase I inhibition assays. 2,3-Dimethoxy-8,9-methylenedioxy-11H-indeno[1,2-c]isoquinoline hydrochloride (14) is a strong topoisomerase I inhibitor and also displays very high cytotoxicity in the NCI cancer cell culture screen (mean graph midpoint of 50 nM). The X-ray crystal structure of norindenoisoquinoline 14 in complex with topoisomerase I and DNA has been solved, providing insight into the structure-activity relationships within this class of new anticancer agents. The number and position of the norindenoisoquinoline substituents have a significant influence on biological activity and demonstrate that substitution on the nitrogen atom is not an absolute requirement for the antitumor effect of the indenoisoquinolines. Removal of the 11-keto group from the lead compound 1 and replacement of the N-alkyllactam with an unsubstituted pyridine ring causes the indenoisoquinoline ring system to flip over in the DNA-enzyme-inhibitor ternary complex. This allows the nitrogen atom to assume the hydrogen bond acceptor role of the 11-keto group, resulting in hydrogen bonding to Arg364.


    Organizational Affiliation

    Department of Medicinal Chemistry and Molecular Pharmacology and the Purdue Cancer Center, School of Pharmacy and Pharmaceutical Sciences, Purdue University, West Lafayette, Indiana 47907, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure


Entity ID: 4
MoleculeChainsSequence LengthOrganismDetails
DNA topoisomerase I
A
592Homo sapiensMutation(s): 0 
Gene Names: TOP1
EC: 5.99.1.2
Find proteins for P11387 (Homo sapiens)
Go to Gene View: TOP1
Go to UniProtKB:  P11387
Entity ID: 1
MoleculeChainsLengthOrganism
5'-D(*AP*AP*AP*AP*AP*GP*AP*CP*TP*T)-3'B10N/A
Entity ID: 2
MoleculeChainsLengthOrganism
5'-D(*(TPC)P*GP*AP*AP*AP*AP*AP*TP*TP*TP*TP*T)-3'C12N/A
Entity ID: 3
MoleculeChainsLengthOrganism
5'-D(*AP*AP*AP*AP*AP*TP*TP*TP*TP*TP*CP*GP*AP*AP*GP*TP*CP*TP*TP*TP*TP*T)-3'D22N/A
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
AI3
Query on AI3

Download SDF File 
Download CCD File 
D
2,3-DIMETHOXY-12H-[1,3]DIOXOLO[5,6]INDENO[1,2-C]ISOQUINOLIN-6-IUM
AI-III-52
C19 H16 N O4
LXDREMZQGAILJU-UHFFFAOYSA-O
 Ligand Interaction
Modified Residues  2 Unique
IDChainsTypeFormula2D DiagramParent
TPC
Query on TPC
C
DNA LINKINGC9 H14 N3 O6 P SDC
PTR
Query on PTR
A
L-PEPTIDE LINKINGC9 H12 N O6 PTYR
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.1 Å
  • R-Value Free: 0.305 
  • R-Value Work: 0.229 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 56.949α = 90.00
b = 114.141β = 94.18
c = 73.499γ = 90.00
Software Package:
Software NamePurpose
CNXrefinement
SCALEPACKdata scaling
HKL-2000data collection
AMoREphasing
HKL-2000data reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-06-21
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance