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Neuraminidase associated with coliphage E that specifically depolymerizes the Escherichia coli K1 capsular
Journal of Virology
|August 1, 1985
Summary
Five Escherichia coli K1-specific bacteriophages possess depolymerase activity. This enzyme, purified from bacteriophage E, rapidly hydrolyzes K1 and meningococcus B antigens.
Area of Science:
- Microbiology
- Enzymology
- Molecular Biology
Background:
- Escherichia coli K1 bacteriophages exhibit depolymerase activity.
- This activity is crucial for phage-host interactions and potential therapeutic applications.
Purpose of the Study:
- To characterize the K1 depolymerase enzyme from bacteriophage E.
- To investigate its purification, enzymatic properties, and substrate specificity.
Main Methods:
- Purification using CsCl density gradient ultracentrifugation, gel filtration, and anion-exchange chromatography.
- Enzyme characterization including molecular weight determination (SDS-PAGE) and activity assays.
- Substrate specificity analysis using various sialic acid-containing antigens.
Main Results:
- The K1 depolymerase was purified 238-fold, yielding a complex with MW 208,000, dissociating into 74,000 and 38,500 MW polypeptides.
- Optimal activity at pH 5.5, inhibited by Ca2+; Km = 7.41 X 10(-3) M.
- Rapid hydrolysis of K1 and meningococcus B antigens; limited hydrolysis of E. coli K92 antigen.
Conclusions:
- The purified K1 depolymerase is a potent enzyme capable of degrading specific bacterial capsular polysaccharides.
- Its activity against E. coli K1 and Neisseria meningitidis serogroup B antigens suggests potential for developing phage-based antimicrobial strategies.
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