Maltase-glucoamylase (MGAM) and sucrase-isomaltase (SI) belong to human intestinal alpha-glucosidase and their N-terminal side catalytic domains are called NtMGAM and NtSI, and their C-terminal side catalytic domains ...Maltase-glucoamylase (MGAM) and sucrase-isomaltase (SI) belong to human intestinal alpha-glucosidase and their N-terminal side catalytic domains are called NtMGAM and NtSI, and their C-terminal side catalytic domains are called CtMGAM and CtSI. As an antidiabetic, alpha-glucosidase inhibitor is required to bind to all of these domains to inhibit disaccharides hydrolysis. Salacinol and kotalanol isolated from Salacia reticulata are novel seed compounds for al-pha-glucosidase inhibitor. Even though the complex structures of NtMGAM or NtSI have been determined experimen-tally, those of CtMGAM and CtSI have not been revealed. Thus, homology modeling for CtMGAM and CtSI has been performed to predict the binding mode of salacinol and its derivatives for each domain. The binding affinities for these compounds were also calculated to explain the experimental structure-activity relationships (SARs). After a docking study of the derivatives to each catalytic domain, the MM/PBSA method has been applied to predict the binding affinities. The predicted binding affinities were almost consistent with the experimental SARs. The comparison of the complex structures and binding affinities provided insights for designing novel compounds, which inhibit all catalytic domains.展开更多
Differences between the inhibitory activities of specific compounds on analogous enzymes isolated from different animal species are one of the critical issues to evaluate when exploring structure-activity relationship...Differences between the inhibitory activities of specific compounds on analogous enzymes isolated from different animal species are one of the critical issues to evaluate when exploring structure-activity relationships. The activity of acarbose is about ten times stronger in rat than in human, and that of neosalacinol is similar in both species. Binding affinities of acarbose and neosalacinol to four catalytic domains of alpha-glucosidases in human and rat were compared to investigate the cause of activity differences among species. Species difference was brought about complicatedly by the balance of interaction with four domains, and the result was indicated that larger ligand would show larger species difference in activity.展开更多
文摘Maltase-glucoamylase (MGAM) and sucrase-isomaltase (SI) belong to human intestinal alpha-glucosidase and their N-terminal side catalytic domains are called NtMGAM and NtSI, and their C-terminal side catalytic domains are called CtMGAM and CtSI. As an antidiabetic, alpha-glucosidase inhibitor is required to bind to all of these domains to inhibit disaccharides hydrolysis. Salacinol and kotalanol isolated from Salacia reticulata are novel seed compounds for al-pha-glucosidase inhibitor. Even though the complex structures of NtMGAM or NtSI have been determined experimen-tally, those of CtMGAM and CtSI have not been revealed. Thus, homology modeling for CtMGAM and CtSI has been performed to predict the binding mode of salacinol and its derivatives for each domain. The binding affinities for these compounds were also calculated to explain the experimental structure-activity relationships (SARs). After a docking study of the derivatives to each catalytic domain, the MM/PBSA method has been applied to predict the binding affinities. The predicted binding affinities were almost consistent with the experimental SARs. The comparison of the complex structures and binding affinities provided insights for designing novel compounds, which inhibit all catalytic domains.
文摘Differences between the inhibitory activities of specific compounds on analogous enzymes isolated from different animal species are one of the critical issues to evaluate when exploring structure-activity relationships. The activity of acarbose is about ten times stronger in rat than in human, and that of neosalacinol is similar in both species. Binding affinities of acarbose and neosalacinol to four catalytic domains of alpha-glucosidases in human and rat were compared to investigate the cause of activity differences among species. Species difference was brought about complicatedly by the balance of interaction with four domains, and the result was indicated that larger ligand would show larger species difference in activity.
