ISSN:
1075-4261
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Physics
Notes:
The interactions between pefloxacin (antimicrobial agent), magnesium, and DNA single or double strand are studied by UV/Vis and surface-enhanced Raman spectroscopies at biological active concentrations: pefloxacin 2 × 10-6, DNA 2 × 10-5, and Mg2+ 10-3M. Pefloxacin interacts with Mg2+ via its carboxylate and pyridinone C4=O groups. In presence of the colloid, with nitrate salts, Mg2+ is positioned near the C4=O and the drug is bound to the Ag surface via the carboxylate. The conjugated rings are tilted over the colloidal particles and a charge transfer from the plasmon of the surface to the pefloxacin occurs, as in absence of salts or in presence of sodium nitrate. With MgCl2, pefloxacin/Mg2+ species are also adsorbed onto the colloid but essentially via the C4=O of the pyridinone ring, the carboxylate being partly bound to Mg2+. The charge transfer is canceled as occurring with NaCl. Magnesium interacts with DNA single or double strand via the phosphodiester groups and amino bases are oriented toward the colloidal surface. Chlorides specifically favor the fixation of the adenine NH2 substituent. At low DNA concentration and in presence of Mg2+, the adsorbed bases are tilted over the Ag surface, more for double- than for single-strand DNA. Ternary pefloxacin-Mg2+-DNA complexes are adsorbed onto the silver surface, via the amino group of the DNA bases and via one carboxylate oxygen of the drug. The ternary complex formed with Mg2+ (nitrate) and DNA modifies the charge transfer from the plasmon of the surface to the drug. © 1997 John Wiley & Sons, Inc. Biospect 3: 31-45, 1997
Additional Material:
14 Ill.
Type of Medium:
Electronic Resource
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