ABSTRACT
<p><b>OBJECTIVE</b>To analyze and compare molecular mechanisms of active ingredients of honeysuckle (chlorogenic acid, CGA) with bovine lactoferrin (BLF) or bovine serum albumin (BSA).</p><p><b>METHOD</b>The spectral experiment and the computer analog technology were combined to determine the binding parameters, energy transfer parameters and thermodynamic functions between CGA and proteins, study the molecular mechanism, and compare the differences in interactive mechanism between CGA and BLF or BSA.</p><p><b>RESULT</b>The interactive mechanism between CGA and BLF or BSA was a dynamic molecular mechanism, whereas the static quenching mechanism existed between the interaction of CGA and BSA, with differences in the bonding intensity due to difference temperature. The binding distance r between CGA and BLF/BSA was very short, indicating the phenomenon of energy transfer. The results of the molecular modeling showed that the main interaction force between CGA and BLF or BSA was hydrogen bonds, together with Van der Waals' forces and hydrophobic effect.</p><p><b>CONCLUSION</b>The computer analog shows consistent results with spectral experiment.</p>
Subject(s)
Animals , Cattle , Humans , Absorption , Drugs, Chinese Herbal , Chemistry , Metabolism , Hydrophobic and Hydrophilic Interactions , Lactoferrin , Chemistry , Metabolism , Lonicera , Chemistry , Models, Molecular , Protein Binding , Protein Conformation , Serum Albumin, Bovine , Chemistry , Metabolism , ThermodynamicsABSTRACT
A combination of spectral experiment and molecular modeling techniques has been used to characterize the binding mechanism between an active component 5-hydroxymethyl-furfural (5-HMF) of traditional Chinese medicine and human serum albumin (HSA) or bovine serum albumin (BSA). The interaction mechanism of 5-HMF binding with HSA/BSA is analyzed. Although the drug can bind with HSA/BSA to form stable complexes, there are some differences in the bond strength. The values of binding distances (r) are different and low, which indicated the occurrence of energy transfer. The drug had conformational effect on HSA/BSA, which resulted in different changes of hydrophobic environment of the binding domain in HSA/BSA. The 'phase diagram' of fluorescence revealed that the changes on the conformational pattern of proteins have been affected by drug conformed to the "all-or-none" pattern. The interactions between drug and protein influenced by Co(II) were also discussed. Its effects acting on 5-HMF-HSA/BSA interactions are different. The computational modeling method was used to study the interaction between 5-HMF and HSA/BSA. The results of molecular model studies revealed that the binding modes for drug-serum albumin systems are mainly hydrophobic interactions and hydrogen bonding. These results are in accordance with spectral results. The research results have given a better theoretical reference for the study of pharmacological mechanism of 5-hydroxymethyl-furfural.
Subject(s)
Animals , Humans , Drugs, Chinese Herbal , Chemistry , Energy Transfer , Furaldehyde , Chemistry , Metabolism , Hydrogen Bonding , Hydrophobic and Hydrophilic Interactions , Ions , Chemistry , Models, Molecular , Molecular Conformation , Protein Binding , Serum Albumin , Chemistry , Metabolism , Serum Albumin, Bovine , Chemistry , Metabolism , Spectrometry, Fluorescence , Spectrophotometry, UltravioletABSTRACT
The binding mechanism between pefloxacin mesylate (PM) and transferrin (Tf) was explored using spectral experiment combined with molecular modeling techniques. The binding parameters and thermodynamic functions of PM-Tf solution system were measured at different temperatures. The effect of PM on molecular conformation of Tf was investigated and the interaction mechanism was also discussed. The results showed that dynamic quenching mechanism occurs with PM binding to Tf. The value of binding distances (r) is low, which indicates the occurrence of energy transfer. The drug had conformational effect on Tf, which resulted in changes of hydrophobic environment of the binding domain in Tf. According to the obtained thermodynamic parameters, the main interaction force between PM and Tf is attributed to hydrophobic bonding. The results of molecular modeling revealed that hydrophobic and hydrogen bonds are main binding forces in the PM-Tf system. These results were in accordance with spectral experiments. The research results have given a better theoretical reference for the study of pharmacological mechanism between protein and quinolone.