An. Veselkov et al., H-1-NMR STUDY OF SELF-ASSOCIATION OF ACTINOMYCIN-D IN AN AQUEOUS-SOLUTION, Journal of structural chemistry, 36(1), 1995, pp. 69-75
This paper presents the results of a proton magnetic resonance study (
500 MHz) of self-association of actinomycin D (AMD) antibiotic in an a
queous solution. The equilibrium constants and thermo- dynamic paramet
ers (Delta H, Delta S) of molecular association as well as the limitin
g values of proton chemical shifts of associate molecules were determi
ned from the concentration and temperature dependences of (1)X NMR che
mical shifts of AMD. The results were analyzed using dimeric and infin
ite-dimensional cooperative models of molecular self-association. The
value of the cooperativity parameter indicates that AMD self-associati
on is anticooperative, i.e., formation of aggregates larger than dimer
s is energetically unfavorable. The values of induced proton chemical
shifts were used to determine the most probable mutual orientation of
chromophores in AMD structure.