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Protein β-O-glucosylation by Legionella LtpM through short consensus sequons G-T/S and S-G
Wei Li1,2, Ling Gao1,3, Shiyong Cui1,2
1College of Chemistry and Molecular Engineering, Peking University, Beijing, China.
Nature Chemical Biology
|July 14, 2025
Summary
Researchers discovered Legionella effector LtpM, a novel enzyme for protein O-glucosylation. This enzyme utilizes short sequons for precise O-glucose addition, enabling new applications in protein engineering and bioorthogonal conjugation.
Area of Science:
- Biochemistry
- Molecular Biology
- Glycobiology
Background:
- Protein O-glycosylation is challenging due to the lack of strict consensus sequences.
- Site-specific engineering of O-glucosylation is difficult, limiting homogeneous O-glycoprotein synthesis.
Purpose of the Study:
- To identify and characterize a novel enzyme for site-specific protein O-glucosylation.
- To explore the mechanism and applications of this enzyme in protein engineering.
Main Methods:
- X-ray crystallography
- Molecular simulation
- Biochemical assays
- Enzyme engineering
Main Results:
- Identified Legionella effector LtpM as a β-O-glucosyltransferase with a unique two-residue sequon specificity (G-T/S and S-G).
- Elucidated the catalytic mechanism involving LtpM residues acting as gatekeepers for substrate binding.
- Demonstrated LtpM's utility for site-specific O-glucosylation of eukaryotic proteins and bioorthogonal conjugation using an azido-glucose analog.
Conclusions:
- LtpM provides a powerful tool for precise O-glucosylation, overcoming previous limitations.
- O-glucose can functionally replace O-linked N-acetylglucosamine in biological systems.
- LtpM facilitates site-specific protein modification and bioorthogonal chemistry.
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