Magnetic microsphere-based methods to study the interaction of teicoplanin with peptides and bacteria.

Abstract

Teicoplanin (teic) from Actinoplanes teichomyceticus is a glycopeptide antibiotic used to treat many gram-positive bacterial infections. Glycopeptide antibiotics inhibit bacterial growth by binding to carboxy-terminal D-Ala-D-Ala intermediates in the peptidoglycan of the cell wall of gram-positive bacteria. In this paper we report the derivatization of magnetic microspheres with teic (teic-microspheres). Fluorescence-based techniques have been developed to analyze the binding properties of the microspheres to two D-Ala-D-Ala terminus peptides. The dissociation constant for the binding of carboxyfluorescein-labeled D-Ala-D-Ala-D-Ala to teic on microspheres was established via fluorimetry and flow cytometry and was determined to be 0.5 x 10(-6) and 3.0 x 10(-6) mol L(-1), respectively. The feasibility of utilizing microparticles with fluorescence methods to detect low levels (the limit of bacterial detection was determined to be 30 colon-forming units; cfu) of gram-positive bacteria has been demonstrated. A simple microfluidic experiment is reported to demonstrate the possibility of developing microsphere-based affinity assays to study peptide-antibiotic interaction.

• Authors: Menake E Piyasena, Lilian J Real, Rochelle A Diamond, H Howard Xu, Frank A Gomez
• Journal: Analytical and bioanalytical chemistry (Anal Bioanal Chem) Vol. 392 Issue 5 Pg. 877-86 (Nov 2008) ISSN: 1618-2650 [Electronic] Germany
• PMID: 18712518 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, U.S. Gov't, Non-P.H.S.)

Chemical References

• Anti-Bacterial Agents
• Fluoresceins
• Peptides
• 6-carboxyfluorescein
• Teicoplanin

Topics

• Actinomycetales (chemistry)
• Anti-Bacterial Agents (chemistry, metabolism)
• Bacteria (chemistry, metabolism)
• Binding Sites
• Flow Cytometry (methods)
• Fluoresceins (chemistry)
• Fluorescence
• Magnetics
• Microfluidics (methods)
• Microscopy, Electron, Scanning (methods)
• Microspheres
• Peptides (chemistry, metabolism)
• Staining and Labeling
• Teicoplanin (chemistry, metabolism)
• Time Factors