Synthesis, characterization and separation of chiral and achiral diastereomers of Schiff base Pd(II) complex: A comparative study of their DNA- and HSA-binding.
A racemic mixture of a new chiral Schiff base ligand (HL: R/S-(1-phenylethylimino)methylnaphtalen-2-ol) has been utilized to prepare Pd(II) complex. Crystallization technique has been employed to separate diastereomeric pairs of Pd(II) complex: (mesoPdL2) and (racPdL2) that in this paper are known as PdL2(1) and PdL2(2), respectively. The synthesized complexes have been characterized by means of elemental analysis (CHN), FT-IR, (1)H and (13)C NMR spectroscopies. Moreover, PdL2(1) has been structurally characterized by single-crystal X-ray diffraction. The geometry around the metal center is square-planar. The interaction of two diastereomers of Pd(II) complex with FS-DNA has been explored, using UV-vis spectroscopy, fluorescence quenching, chemometrics and viscosity measurement methods. The PdL2(1) exhibited higher binding constant, about 10-fold, (1.0×10(6)M(-1)) as compared to PdL2(2) (1.51.5×10(5)M(-1)). Moreover, the human serum albumin (HSA) binding ability has been monitored by absorption, quenching of tryptophan fluorescence emission and circular dichroism (CD) studies. The slight difference is observed between HSA binding affinity with the complexes: PdL2(1) (6.2×10(4)M(-1)) and PdL2(2) (3.3×10(4)M(-1)). Also, the thermodynamic parameters were determined at three different temperatures (298, 308 and 318K). In this study, molecular docking was also carried out to confirm and illustrate the specific DNA- and HSA-binding of the Pd(II) complexes. In the PdL2(1)-HSA system a T-shaped π-π interaction with PHE206 was observed. While in the PdL2(2)-HSA system there are a hydrogen bond, a π-cation and two T-shaped π-π interactions with ASB324, LYS212 and PHE228, respectively. The groove binding mode of DNA interaction has been proposed for both diastereomers.
Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Iran.
Zahra
Z
Kazemi
Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Iran. Electronic address: h.a.rudbari@sci.ui.ac.ir.
Hadi
H
Amiri Rudbari
Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Iran. Electronic address: m.sahihi@chem.ui.ac.ir.
Mehdi
M
Sahihi
Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Iran. Electronic address: mirkhani@sci.ui.ac.ir.
Valiollah
V
Mirkhani
Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Iran.
Majid
M
Moghadam
Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Iran.
Sharam
S
Tangestaninejad
Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Iran.
Iraj
I
Mohammadpoor-Baltork
Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Iran.
Gholamhassan
G
Azimi
Department of Bioinformatics, Laboratory of Bioinformatics and Drug Design, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran.
Sajjad
S
Gharaghani
Department of Biotechnology, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan, Iran.
Abolghasem Abbasi
AA
Kajani
D000818:Animals; D060326:Chemistry Techniques, Synthetic; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D004735:Energy Transfer; D006801:Humans; D008024:Ligands; D062105:Molecular Docking Simulation; D009690:Nucleic Acid Conformation; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D010165:Palladium / Q000737:chemistry*; D011487:Protein Conformation; D012545:Schiff Bases / Q000737:chemistry; D012709:Serum Albumin / Q000737:chemistry / Q000378:metabolism*; D013237:Stereoisomerism; D014783:Viscosity
D008024:Ligands; D009942:Organometallic Compounds; D012545:Schiff Bases; D012709:Serum Albumin; D010165:Palladium; D004247:DNA
DNA binding; Diastereomers separation; HSA binding; Molecular docking; Pd(II) Schiff base complex