DockingServer

Activity of Indoloquinazolinone alkaloids (Tryptanthrine) against DNA recombination protein RecA [Mycobacterium tuberculosis H37Rv]]

Author: Mr. Ankit Tripathi - 12/01/09, 08:42

More docking results of Mr. Ankit Tripathi Address: CSIR-NISCAIR

Abstract: DNA recombination protein RecA [Mycobacterium tuberculosis H37Rv], a protein plays an important role in the growth, regulation, differentiation of tuberculosis and is considered an important therapeutic target against Mycobacterium tuberculosis. In this study we made in silico attempt to see the efficacy to known natural Indoloquinazolinone alkaloids compound Tryptanthrine against RecA [Mycobacterium tuberculosis H37Rv].









Result table

Rank
 
Est. Free Energy
of Binding
Est. Inhibition
Constant, Ki
vdW + Hbond
+ desolv Energy
Electrostatic
Energy
Total Intermolec.
Energy
Frequency
 
1
-6.20 kcal/mol
28.76 uM
-6.18 kcal/mol
-0.02 kcal/mol
-6.20 kcal/mol
90
 





Interaction Table

hydrogen bonds
polar
hydrophobic
pi-pi
other
  N2 (6)
  [2.68]		 – ARG96 (O)
  O2 (11)
  [3.38]		 – ARG96 (NH1)
  C11 (15)
  [3.75]		 – ALA65 (CB)
  C9 (13)
  [3.09]		 – PHE9 (CB)
  C10 (14)
  [2.99]		 – ARG7 (CB)
       
  C13 (17)
  [3.67]		 – ARG7 (CB)
       
  C13 (17)
  [3.55]		 – THR16 (CG2, OG1)
       
  C10 (14)
  [3.87]		 – THR16 (CG2)
       
  N2 (6)
  [3.63]		 – VAL98 (CB)
       
  C12 (16)
  [3.69]		 – ARG405 (NH2)
       
  C15 (19)
  [2.95]		 – ARG405 (NH2)
       
  O2 (11)
  [3.86]		 – VAL432 (CG1)
 








Docking calculations were carried out using DockingServer (Bikadi, Hazai, 2009). The MMFF94 force field (Halgren, 1998) was used for energy minimization of ligand molecule (tryptanthrine) using DockingServer. Gasteiger partial charges were added to the ligand atoms. Non-polar hydrogen atoms were merged, and rotatable bonds were defined.
Docking calculations were carried out on RecA protein model. Essential hydrogen atoms, Kollman united atom type charges, and solvation parameters were added with the aid of AutoDock tools (Morris, Goodsell et al., 1998). Affinity (grid) maps of 20×20×20 Å grid points and 0.375 Å spacing were generated using the Autogrid program (Morris, Goodsell et al., 1998). AutoDock parameter set- and distance-dependent dielectric functions were used in the calculation of the van der Waals and the electrostatic terms, respectively.
Docking simulations were performed using the Lamarckian genetic algorithm (LGA) and the Solis & Wets local search method (Solis and Wets, 1981). Initial position, orientation, and torsions of the ligand molecules were set randomly. Each docking experiment was derived from 10 different runs that were set to terminate after a maximum of 250000 energy evaluations. The population size was set to 150. During the search, a translational step of 0.2 Å, and quaternion and torsion steps of 5 were applied.



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