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Defining Substrate Specificities for Lipase and Phospholipase Candidates
Published on: November 23, 2016
Molecular basis for substrate selectivity and specificity by an LPS biosynthetic enzyme
Yaozhong Zou1, Chong Li, Joseph S Brunzelle
1Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, USA.
Biochemistry
|March 21, 2007
Summary
Structural insights into GDP-mannose mannosyl hydrolase (Gmm) reveal how it regulates lipopolysaccharide (LPS) diversity in Gram-negative bacteria. These findings provide a basis for designing novel inhibitors targeting bacterial LPS biosynthesis.
Area of Science:
- Biochemistry
- Structural Biology
- Microbiology
Background:
- Lipopolysaccharide (LPS) diversity is crucial for Gram-negative bacterial persistence and pathogenesis.
- GDP-mannose mannosyl hydrolase (Gmm) is a Nudix hydrolase that modulates mannose levels in LPS biosynthesis.
Purpose of the Study:
- To elucidate the structural basis of Gmm's substrate specificity and promiscuity.
- To provide a structural framework for understanding Gmm's enzymatic activity.
- To identify potential targets for novel antibacterial inhibitors.
Main Methods:
- High-resolution crystallography of Gmm from enteropathogenic E. coli O128.
- Determination of apo enzyme structure.
- Cocrystallization with substrates, products, and an inactive mutant.
Main Results:
- Seven crystal structures reveal Gmm's interactions with GDP-mannose, GDP-glucose, GDP-fucose, and Mg2+-GDP.
- Structures explain substrate specificity and reconcile kinetic data.
- Enzyme active site formation is dependent on substrate/product binding, revealing a unique catalytic mechanism.
Conclusions:
- The crystal structures provide a detailed molecular understanding of Gmm function.
- These insights can guide the rational design of inhibitors targeting bacterial LPS synthesis.
- Gmm's substrate-dependent active site formation offers a novel avenue for therapeutic intervention.
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