Abstract
CapE is an essential enzyme for the synthesis of capsular polysaccharide (CP) of pathogenic strains of Staphylococcus aureus. Herein we demonstrate that CapE is a 5-inverting 4,6-dehydratase enzyme. However, in the absence of downstream enzymes, CapE catalyzes an additional reaction (5-back-epimerization) affording a by-product under thermodynamic control. Single-crystal X-ray crystallography was employed to identify the structure of the by-product. The structural analysis reveals a network of coordinated motions away from the active site governing the enzymatic activity of CapE. A second dynamic element (the latch) regulates the enzymatic chemoselectivity. The validity of these mechanisms was evaluated by site-directed mutagenesis.
Original language | English |
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Pages (from-to) | 3824-3830 |
Number of pages | 7 |
Journal | FEBS Letters |
Volume | 587 |
Issue number | 23 |
DOIs | |
Publication status | Published - 2013 Nov 29 |
Externally published | Yes |
Keywords
- Capsular polysaccharide
- Conformational change
- Pathogenic bacterium
- SDR enzyme
- Staphylococcus aureus
- UDP-sugar
- X-ray crystallography
ASJC Scopus subject areas
- Biophysics
- Structural Biology
- Biochemistry
- Molecular Biology
- Genetics
- Cell Biology