Biopolymers and cell. 2005; 21 (4): 358 - 364

The binding of actinocin antibiotics to polyphosphate matrix

E. B. Kruglova, T. V. Bolbukh, N. A. Gladkovskaya, Ju. N. Bliznyuk

The complexes of actinocin derivatives ActII and ActIII (analogues of actinomycin D) with polyphosphate were studied by spectrophotometry and Raman spectroscopy methods. All studies were carried out in a phosphatic buffer solution (pH 6,86) with total concentration of Na⁺ and K⁺ equal to 7*10^-3 M. The DALSPH program of optimization of spectrophotometric concentration dependences was used for calculations of complexes spectra and thermodynamic binding parameters. The values of binding constants and binding site sizes, the spectra of monomeric and aggregated complexes of actinocin derivatives for ActII and ActIII were obtained by the analysis of spectrophotometrical titration curves. The basic groups of atoms participating in formation of different types of complexes were determined by the Raman spectroscopy method. The amino group of actinocin derivative was shown to be bound to P=O group of polyphosphate matrix at monomeric binding mode.

Key words: spectrophotometry, Raman spectroscopy, polyphosphate, actinocin derivatives.