Solution-state dynamics of sugar-connected spin probes in sucrose solution as studied by multiband (L-, X-, and W-band) electron paramagnetic resonance

J Magn Reson. 2003 Jul;163(1):174-81. doi: 10.1016/s1090-7807(03)00174-5.

Abstract

A multiband (L-band, 0.7GHz; X-band, 9.4GHz; and W-band, 94GHz) electron paramagnetic resonance (EPR) study was performed for two glycosidated spin probes, 4-(alpha,beta-D-glucopyranosyloxy)-TEMPO (Glc-TEMPO) and 4-(alpha,beta-D-lactopyranosyloxy)-TEMPO (Lac-TEMPO), and one non-glycosylated spin probe, 4-hydroxy-TEMPO (TEMPOL), where TEMPO=2,2,6,6-tetramethyl-1-piperidinyloxyl, to characterize fundamental hydrodynamic properties of sugar-connected spin probes. The linewidths of these spin probes were investigated in various concentrations of sucrose solutions (0-50wt%). The multiband approach has allowed full characterization of the linewidth parameters, providing insights into the molecular shapes of the spin probes in sucrose solution. The analysis based on the fast-motional linewidth theory has yielded anisotropy parameters of rho(x) approximately 2.6 and rho(y) approximately 0.9 for Glc-TEMPO, and rho(x) approximately 4.2 and rho(y) approximately 0.9 for Lac-TEMPO. These values indicate that the glycosidated spin probes have a prolate-type molecular shape elongated along the x-axis (NO(rad) axis) with Lac-TEMPO elongated more remarkably, consistent with their molecular structures. The interaction parameters k (the ratios of the effective hydrodynamic volumes to the real ones) corrected for the difference in molecular shape have been estimated and found to have the relation k(TEMPOL)<k(Glc-TEMPO) approximately k(Lac-TEMPO). This agrees with the expectation that glycosidated spin probes can have stronger hydrogen bonding to water. Glycosidated spin probes are expected to be useful for probing sugar-involving interactions, which commonly occur in biological systems. Thus this study will provide an indispensable basis for such spin-probe studies.

Publication types

  • Comparative Study
  • Evaluation Study
  • Validation Study

MeSH terms

  • Anisotropy
  • Computer Simulation
  • Cyclic N-Oxides / chemistry*
  • Electron Spin Resonance Spectroscopy / methods*
  • Microwaves*
  • Models, Molecular*
  • Molecular Conformation
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Solutions / chemistry*
  • Spin Labels / chemical synthesis
  • Sucrose / chemistry*

Substances

  • Cyclic N-Oxides
  • Solutions
  • Spin Labels
  • Sucrose
  • TEMPO