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Nanomechanics of Drug-target Interactions and Antibacterial Resistance Detection
Published on: October 25, 2013
Chiral recognition mechanisms with macrocyclic glycopeptide selectors
1Laboratoire des Sciences Analytiques, Université de Lyon, CNRS, Bat. CPE, Villeurbanne, France. berthod@univ-lyon1.fr
Chirality
|August 14, 2008
Summary
Macrocyclic glycopeptide selectors, like vancomycin, are effective chiral chromatography tools for separating enantiomers. Teicoplanin aglycone (TAG) offers superior amino acid separation, while sugars enable broader analyte recognition.
Area of Science:
- Analytical Chemistry
- Organic Chemistry
- Biochemistry
Background:
- Macrocyclic glycopeptides, natural antibiotics, function as potent chiral selectors.
- Four such selectors (ristocetin, teicoplanin, vancomycin, TAG) are commercialized as chiral stationary phases (CSPs) in chromatography.
- Amino acid recognition primarily involves charge-charge interactions between the analyte and selector.
Purpose of the Study:
- To investigate the enantioseparation capabilities of macrocyclic glycopeptide CSPs for various analytes.
- To elucidate the chiral recognition mechanisms, including the role of selector structure and mobile phase conditions.
- To compare the effectiveness of different CSPs, including teicoplanin aglycone (TAG).
Main Methods:
- Utilized four commercial macrocyclic glycopeptide chiral stationary phases (CSPs).
- Employed chromatographic techniques with varying mobile phase compositions (normal phase, reversed phase, polar ionic mode).
- Conducted thermodynamic studies and applied linear solvation energy relationships (LSER) to analyze separation mechanisms.
Main Results:
- Teicoplanin aglycone (TAG) demonstrated superior performance for amino acid enantioseparations compared to other CSPs.
- Carbohydrate moieties on selectors facilitate recognition of analytes like beta-blockers, which TAG alone cannot resolve.
- Enantioseparations were found to be enthalpy-driven in normal and reversed-phase modes, and either enthalpy- or entropy-driven in polar ionic mode.
- LSER analysis indicated significant roles for charge-induced dipole interactions and steric effects with the teicoplanin CSP for molecular solutes.
Conclusions:
- Macrocyclic glycopeptide CSPs offer complementary enantioselectivity for diverse analytes.
- The structural features of selectors, including carbohydrate units and aglycones, dictate their separation capabilities.
- Understanding thermodynamic driving forces and interaction mechanisms is crucial for optimizing chiral separations.
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