The TrkA inhibitors were extensively explored to detect their optimal physicochemical properties and pharmacophoric binding modes, which were converted into numeric descriptors and allowed to compete within the context of the Genetic Function Algorithm (GFA) approximations to find the subset of terms that correlates best with the activity.
LD studies indicated that the ruthenium complexes interact with ct-DNA through a mixed binding mode, which is influenced by complex concentration and chirality.
X-ray crystallography commonly suggests the existence of a single well-defined state, termed binding mode, which is generally assumed to be consistent in a series of similar ligands and therefore used for the following optimization process.
Calculated binding free energies using molecular MM/PB(GB SA approach are in good agreement with experimental results, suggesting that the inhibitors share the same binding mode, which is stabilized by hydrophobic interactions and by a conserved network of hydrogen bonds.
A possible explanation is that compound 4 actually adopts a different preferred binding mode, which was not detected in the docking simulations.
A subsequently determined structure of Sorafenib with c-Raf revealed an overall similar binding mode, which was termed a 'type II' binding mode.
The noncompetitive pattern of inhibition in the absence of matched dNTP can be explained by the existence of an alternative Pol X−DNA binding mode which is independent of dNTP binding.
The complete filling of the binding channels is generally termed the "70-base" or "65-base" binding mode and is differentiated from a "35-base" binding mode, which is favored by low ionic strength and a high ratio of SSB to ssDNA (1, 10).
The crystal structures of four exemplar benzimidazole inhibitors bound to CHK2 all show a single binding mode which is in excellent agreement with that obtained through flexible docking, but different from the prediction of unconstrained rigid docking, and significantly different from the binding modes previously postulated in the literature.
These results suggest a transient but specific antigen-binding mode, which is characterized by a high on-rate combined with a high off-rate, for both chromobodies in living cells.
