Although the GABAA receptor(GABAAR)has been proposed as the main action site for sevoflurane,isoflurane,halothane,enflurane,propofol,and benzodiazepines(BZDs),binding of these anesthetics with high-resolution structur...Although the GABAA receptor(GABAAR)has been proposed as the main action site for sevoflurane,isoflurane,halothane,enflurane,propofol,and benzodiazepines(BZDs),binding of these anesthetics with high-resolution structures of the GABAAR have been rarely examined by comparative docking analyses.Moreover,various combinations of ligands on more GABAARs with various subtypes need to be analyzed to understand the elaborate action mechanism of GABAARs better because some GABAA ligands showed specificity toward the distinct subtypes of the GABAAR.Methods:We performed in silico docking analysis to compare the binding modes of sevoflurane,isoflurane,halothane,enflurane,propofol,and BZDs to the GABAAR based on one of the most recently provided 3D structures.We performed the docking analysis and the affinity-based ranking of the binding sites.Results:Our docking studies revealed that isoflurane,halothane,and enflurane docked in an extracellular domain(ECD)on GABAARs,in contrast to sevoflurane.Conclusion:Our results supported a multi-site mechanism for the allosteric modulation of propofol.Propofol was bound to the pore or favored various subsites in the transmembrane domain(TMD).Our result confirmed that different chemically related BZD ligands interact via distinct binding modes rather than by using a common binding mode,as previously suggested.展开更多
Whey proteins are versatile molecules with great nutritional value and multiple functionalities. One of these functionalities is the ability to bind and protect bioactive compounds. Lutein and folic acid (FA) are bioa...Whey proteins are versatile molecules with great nutritional value and multiple functionalities. One of these functionalities is the ability to bind and protect bioactive compounds. Lutein and folic acid (FA) are bioactive molecules with a remarkable relevance for developing functional foods. FA contributes in preventing the occurrence of neural tube defects during the early stages of life, while lutein is a macular pigment that contributes to the development of the retina. In this context, the aim of this work was to evaluate the ability of the main whey proteins, β-lactoglobulin and α-lactalbumin, to simultaneously bind FA and lutein. The binding was evaluated through intrinsic fluorescence quenching and molecular docking, and the impact of the binding on the secondary structure and denaturation temperature of the proteins were also evaluated through circular dichroism and differential scanning calorimetry, respectively. Both proteins had similar behavior on the performed analyses. The multi-binding ability of β-lactoglobulin and α-lactalbumin to FA and lutein was observed. The presence of the first ligand slightly reduced the association constant between the second one and the proteins;in particular for the binding of lutein in the presence of FA (reduction of around 36%–38% on the KSV values). Molecular docking indicated that both ligands interact, preferentially, on the same region of the studied protein structures. The secondary structure of the proteins, as well as their denaturation temperatures were minimally impacted by the presence of these ligands, themselves. Our results may contribute to the development of multi-functional protein-rich food products.展开更多
文摘Although the GABAA receptor(GABAAR)has been proposed as the main action site for sevoflurane,isoflurane,halothane,enflurane,propofol,and benzodiazepines(BZDs),binding of these anesthetics with high-resolution structures of the GABAAR have been rarely examined by comparative docking analyses.Moreover,various combinations of ligands on more GABAARs with various subtypes need to be analyzed to understand the elaborate action mechanism of GABAARs better because some GABAA ligands showed specificity toward the distinct subtypes of the GABAAR.Methods:We performed in silico docking analysis to compare the binding modes of sevoflurane,isoflurane,halothane,enflurane,propofol,and BZDs to the GABAAR based on one of the most recently provided 3D structures.We performed the docking analysis and the affinity-based ranking of the binding sites.Results:Our docking studies revealed that isoflurane,halothane,and enflurane docked in an extracellular domain(ECD)on GABAARs,in contrast to sevoflurane.Conclusion:Our results supported a multi-site mechanism for the allosteric modulation of propofol.Propofol was bound to the pore or favored various subsites in the transmembrane domain(TMD).Our result confirmed that different chemically related BZD ligands interact via distinct binding modes rather than by using a common binding mode,as previously suggested.
基金financed by the S˜ao Paulo Research Foundation(FAPESP)(Grants 2017/09214-4 and 2018/09304-6)The authors thank the Food Chemistry Laboratory(FEA/UNICAMP)for chromatographic analysis(FAPESP multiuser equipment:grants 2018/03822-5 and 2018/23752-1)Also,this research used facilities of the Brazilian Biorenewables National Laboratory(LNBR),part of CNPEM as well.The Macromolecules facility staff is acknowledged for the assistance during CD experiments(proposal MAC-28004).
文摘Whey proteins are versatile molecules with great nutritional value and multiple functionalities. One of these functionalities is the ability to bind and protect bioactive compounds. Lutein and folic acid (FA) are bioactive molecules with a remarkable relevance for developing functional foods. FA contributes in preventing the occurrence of neural tube defects during the early stages of life, while lutein is a macular pigment that contributes to the development of the retina. In this context, the aim of this work was to evaluate the ability of the main whey proteins, β-lactoglobulin and α-lactalbumin, to simultaneously bind FA and lutein. The binding was evaluated through intrinsic fluorescence quenching and molecular docking, and the impact of the binding on the secondary structure and denaturation temperature of the proteins were also evaluated through circular dichroism and differential scanning calorimetry, respectively. Both proteins had similar behavior on the performed analyses. The multi-binding ability of β-lactoglobulin and α-lactalbumin to FA and lutein was observed. The presence of the first ligand slightly reduced the association constant between the second one and the proteins;in particular for the binding of lutein in the presence of FA (reduction of around 36%–38% on the KSV values). Molecular docking indicated that both ligands interact, preferentially, on the same region of the studied protein structures. The secondary structure of the proteins, as well as their denaturation temperatures were minimally impacted by the presence of these ligands, themselves. Our results may contribute to the development of multi-functional protein-rich food products.
