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Published March 2007 | public
Journal Article

Determination of Binding Constants of Polyethylene Glycol Vancomycin Derivatives to Peptide Ligands Using Affinity Capillary Electrophoresis

Abstract

Vancomycin (Van) from Streptomyces orientalis has been derivatized with polyethylene glycol [PEG; PEG-550 (1), 750 (2), 1,100 (3), 2,000 (4), 5,000 (5), and 8,000 (6) g mol−1] at the N-terminus of the glycopeptide backbone and their binding to d-Ala-d-Ala terminus peptides assessed using affinity capillary electrophoresis (ACE). Utilizing ACE, a plug of Van-PEG and non-interacting standards are injected and electrophoresed. Analysis of the change in the relative migration time ratio of the Van-PEG species, relative to the non-interacting standards, as a function of the concentration of peptide, yields a value for the binding constant (K_b). Values of K_b for N-acetyl-d-Ala-d-Ala, 7 to the Van-PEG derivatives are weaker than those for N_α,N_ε-diacetyl-Lys-d-Ala-d-Ala, 8 (for example, values of K_b for 7-1 and 8-1 are 1.8 and 47.7 × 10^3 M^(−1), respectively). These results demonstrate that derivatization of Van with PEG has little effect on the affinity of d-Ala-d-Ala peptide ligands to it. The findings further prove the versatility of ACE and its ability to estimate binding parameters of ligands to antibiotics.

Additional Information

© Friedr. Vieweg & Sohn Verlag/GWV Fachverlage GmbH 2006. Received: 2 August 2006 / Revised: 7 November 2006 / Accepted: 21 November 2006 / Online publication: 21 December 2006 The authors gratefully acknowledge financial support for this research by grants from the National Science Foundation (CHE-0515363, DMR-0351848, DMR-0080065, DMR-0520565), and the National Institutes of Health (1R15 AI055515-01, 1R15AI65468-01, and GM54939).

Additional details

Created:
August 22, 2023
Modified:
October 25, 2023