Spectroscopic investigation on the binding of bioactive pyridazinone derivative to human serum albumin and molecular modeling.
The interaction between a novel promising pyridazinone derivative (5-chloro-2-nitro-N-(4-(6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)phenyl)benzamide (CNPB)) and human serum albumin (HSA) under physiological conditions has been investigated systematically by fluorescence spectroscopy, UV absorption spectroscopy, circular dichroism (CD) and molecular modeling. From the spectra obtained, it was observed that CNPB had a strong ability to quench the intrinsic fluorescence of HSA through a static quenching procedure. The site binding constants (K(b)) were 4.22 x 10(4) and 3.32 x 10(4)M(-1) at 290 and 300 K, respectively. The alterations of protein secondary structure in the presence of CNPB were qualitative and quantitative calculated by the results from CD and synchronous fluorescence. In addition, the thermodynamic standard enthalpy (DeltaH) and standard entropy (DeltaS) for the reaction were calculated to be -17.35 kJ mol(-1) and 9.57 J mol(-1)K(-1), respectively. These results showed that the binding of CNPB to HSA was mainly of hydrophobic interaction, but the hydrogen bonding and electrostatic interaction could not be excluded. Furthermore, the study of molecular modeling also indicated that CNPB could strongly bind to the site I (subdomain IIA) of HSA mainly by hydrophobic interaction and there were hydrogen bond interactions between CNPB and the residue His242.
Wang
Teng
T
Center for Instrumental Analysis, Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, Nanjing 210009, China.
Xiang
Bingren
B
Wang
Ying
Y
Chen
Changyun
C
Dong
Ying
Y
Fang
Huisheng
H
Wang
Min
M
D001549:Benzamides / Q000737:chemistry*; D002942:Circular Dichroism; D006801:Humans; D008958:Models, Molecular; D011485:Protein Binding; D017433:Protein Structure, Secondary / Q000187:drug effects; D011724:Pyridazines / Q000737:chemistry*; D012709:Serum Albumin / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D013816:Thermodynamics
C531957:5-chloro-2-nitro-N-(4-(6-oxo-1,4,5,6-teetrahydroopyridazin-3-yl)phenyl)benzamide; D001549:Benzamides; D011724:Pyridazines; D012709:Serum Albumin