The in vitro nuclear aggregates of polyamines

Natural polyamines (putrescine, spermidine, and spermine) self-assemble in a simulated physiol. environment (50 mM sodium phosphate buffer, pH 7.2), generating in vitro nuclear aggregates of polyamines (ivNAPs). These supramol. compds. are similar in structure and mol. mass to naturally occurring cellular nuclear aggregates of polyamines, and they share the ability of NAPs to interact with and protect the genomic DNA against nuclease degrdn. Three main ivNAP compds. were sepd. by gel permeation chromatog. Their elution was carried out with 50 mM sodium phosphate buffer supplemented with 150 mM NaCl. Freezing and thawing of selected chromatog. fractions obtained by GPC runs in which the mobile phase was sodium phosphate buffer not supplemented with NaCl yielded three different microcrystallites, specifically corresponding to the ivNAPs, all of which were able to bind DNA. In this study, we demonstrated that in vitro self-assembly of polyamines and phosphates is a spontaneous, reproducible and inexpensive event, and provided the indications for the prodn. of the ivNAPs as a new tool for manipulating the genomic DNA machinery.