Structural insights into the ligand-binding hot spots of APEX1: an in silico analysis

AbstractHuman apurinic/apyrimidinic endonuclease (APEX1) is a multifunctional protein involved in the repair of DNA damage. It plays a vital role in the base excision repair. Overexpression of APEX1 is observed in a variety of cancers. High APEX1 expression has been associated with deprived result to radio and chemotherapy. It also plays an important role in therapeutic agent resistance and disease suppression. If APEX1 activities could be regulated, the protein would be a favorable and efficient cancer target. So far, inhibitor binding site of APEX1 is not studied in detail. The present study focuses on the identification of ligand-binding hot spot residues of APEX1. Docking studies were performed on seventy-one recently reported APEX1 inhibitors. The docking results identified that most of the compounds with biphenyl moiety occupied the same binding site. Majority of compounds were found to form hydrogen bond interaction with Asn174, Arg156, His309, Tyr128, Asn212, Arg181 and Asn226 and hydrophobic interaction with Phe266, Trp280 and Tyr128. The results could provide useful structural insights about the binding mode of APEX1 inhibitors and the crucial hot spot residues which are essential for ligand recognition.

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