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Published November 2008 | public
Journal Article

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 0.5x10^-6 and 3.0x10^-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.

Additional Information

© Springer-Verlag 2008. Received: 2 June 2008 / Revised: 24 July 2008 / Accepted: 29 July 2008 / Published online: 21 August 2008. The authors gratefully acknowledge financial support for this research by grants from the National Science Foundation (CHE-0515363, CBET-0723271, DMR-0351848 and DMR-0520565), and the National Institutes of Health (1R15AI65468–01 to F.A.G.; P20MD001824 to H.H.X.).

Additional details

Created:
August 22, 2023
Modified:
October 17, 2023