Structural analysis and calf thymus DNA/HSA binding properties of new carbazole derivative containing piperazine

Abstract

A new carbazole derivative, named N-(9-ethyl-9H-carbazole-3-ly)-3-(4-methylpiperazine-1-ly)propanamide (Cpp) was synthesized and its interaction with calf thymus DNA (ctDNA) and human serum albumin (HSA) has been studied by fluorescence and UV absorption spectroscopies and molecular docking. The fluorescence assays showed that the quenching mechanism was static and the complex formation between Cpp and DNA/HSA. Thermodynamic parameters including the positive values of both Delta H and Delta S indicated that hydrophobic forces played main role in stabilizing for each complex. In addition the binding properties of DNA were examined with competition experiments of two fluorescence probes (EB and H33258), iodide ion quenching, ionic strength effect and absorption. The data pointed that Cpp inserted into the minor groove binding with the A-T section of DNA. The obtained experimental data were supported and validated with computational analyzes by molecular docking. The current results shed important and useful insight into binding interactions and affinities between other similar carbazole derivatives and DNA/protein as biomolecules.