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Updated: Jul 3, 2026
10:17
Pulse-chase Analysis of N-linked Sugar Chains from Glycoproteins in Mammalian Cells
Published on: April 27, 2010
Golgi alpha-mannosidase II cleaves two sugars sequentially in the same catalytic site
Niket Shah1, Douglas A Kuntz, David R Rose
1Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
Summary
Golgi alpha-mannosidase II (GMII) is crucial for complex N-glycan synthesis. Structural insights reveal its catalytic mechanism, aiding the development of targeted cancer inhibitors.
Area of Science:
- Biochemistry
- Glycobiology
- Structural Biology
Background:
- Golgi alpha-mannosidase II (GMII) is a critical enzyme in the N-linked glycosylation pathway.
- GMII catalyzes a key step in complex N-glycan synthesis, making it a target for cancer therapies.
Purpose of the Study:
- To elucidate the high-resolution crystal structure of Drosophila melanogaster GMII (dGMII).
- To understand the catalytic mechanism and substrate binding of dGMII.
Main Methods:
- X-ray crystallography of nucleophile mutant dGMII.
- Structure determination of enzyme-substrate and enzyme-precursor complexes, as well as the unliganded mutant.
Main Results:
- Identification of three distinct sugar-binding subsites within the dGMII active site.
- Elucidation of the complete catalytic process, including bond cleavage order and substrate rearrangement.
- Demonstration of likely conservation of this mechanism across GMII enzymes.
Conclusions:
- The determined structures provide a detailed understanding of dGMII's catalytic mechanism.
- This mechanistic insight is essential for designing specific GMII inhibitors for therapeutic applications.
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