Negureanu, Lacramioara; Salsbury, Freddie R., Jr.
Destabilization of the MutS alpha's protein-protein interface due to binding to the DNA adduct induced by anticancer agent carboplatin via molecular dynamics simulations
JOURNAL OF MOLECULAR MODELING, 19:4969-4989, NOV 2013

DNA mismatch repair (MMR) proteins maintain genetic integrity in all organisms by recognizing and repairing DNA errors. Such alteration of hereditary information can lead to various diseases, including cancer. Besides their role in DNA repair, MMR proteins detect and initiate cellular responses to certain type of DNA damage. Its response to the damaged DNA has made the human MMR pathway a useful target for anticancer agents such as carboplatin. This study indicates that strong, specific interactions at the interface of MutS alpha in response to the mismatched DNA recognition are replaced by weak, non-specific interactions in response to the damaged DNA recognition. Data suggest a severe impairment of the dimerization of MutS alpha in response to the damaged DNA recognition. While the core of MutS alpha is preserved in response to the damaged DNA recognition, the loss of contact surface and the rearrangement of contacts at the protein interface suggest a different packing in response to the damaged DNA recognition. Coupled in response to the mismatched DNA recognition, interaction energies, hydrogen bonds, salt bridges, and solvent accessible surface areas at the interface of MutS alpha and within the subunits are uncoupled or asynchronously coupled in response to the damaged DNA recognition. These pieces of evidence suggest that the loss of a synchronous mode of response in the MutS alpha's surveillance for DNA errors would possibly be one of the mechanism(s) of signaling the MMR-dependent programed cell death much wanted in anticancer therapies. The analysis was drawn from dynamics simulations.

DOI:10.1007/s00894-013-1998-2

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