Fuconojirimycin C1取代衍生物對嗜熱菌岩藻糖水解酶之抑制研究
Study of the Slow-Binding Inhibition of 1-Substituted Fuconojirimycins against Thermotoga maritima alpha-L-Fucosidase
Date Issued
2005
Date
2005
Author(s)
Lin, Yu-Nong
DOI
zh-TW
Abstract
Abstract
alpha-L-Fucosidases are exo-glycosidases to cleave alpha-linked L-fucose residues from the glycoconjugates that usually participate in a variety of important biological processes. Decreased α-L-fucosidase activity is related to a number of pathological conditions such as inflammation, cancer, cystic fibrosis and fucosidosis. Therefore, discovery of potent and selective inhibitors certainly sheds light on the study of their functions and development of therapeutic agents.
Previously, our lab established rapid synthesis of fuconojirimycin-based inhibitors in microtiter plates for high-throughput screening, which rapidly identified potent and selective inhibitors against alpha-L-fucosidases from Thermotoga maritima and human tissue. Interestingly, slow, tight-binding inhibition was found in the study of the former enzyme, distinct from the reversible inhibition of the latter. These molecules thus have higher affinity with the Thermotoga maritima alpha-L-fucosidases than that with the human enzyme, with the best inhibitor exhibiting inhibitory difference up to 5,400-fold .
According to the homology modeling and molecular docking, the drastic difference in the inhibition was probably attributed to the hydrophobic aglycon binding site that was absent in the human fucosidase. To decipher the interesting distinction at molecular level, six residues (W58, F59, Y64, L191, M225 and Y267) likely involved in the aglycon binding were changed to alanine by site-directed mutagenesis. Slow-binding inhibition was diminished to different degrees in activity assays of these mutants. Futhermore, intrinsic fluorescence analysis indicated that Y64A and Y267A mutants had no significant change upon inhibitor titration and thus behaved like their human counterpart. The result is not only consistent with the corresponding kinetic data, but also corroborates the role of proposed hydrophobic residues in the aglycon binding site.
Subjects
岩藻糖水解酶
抑制劑
slow-binding
fucosidase
inhibitor
fuconojirimycin
SDGs
Type
other
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