DNA condensation with polyamines: I. Spectroscopic studies

摘要: Abstract The addition of polyamines with three or four positive charges to very dilute solutions phage T7 DNA leads a co-operative condensation. reaction is rapid and the remains in B-form as characterized by circular dichroism. particles which are formed roughly size particle when they prepared for electron microscopy. This aspect discussed more completely accompanying paper (Chattoraj et al., 1978). Most experiments were performed at low ionic strength (roughly 0.002 m ) triamine, spermidine. also occurs 0.15 -sodium chloride but here accompanied slow irreversible effects evidently due aggregation since commensurate increase turbidity. Consequently, most have been done under reversible conditions. Neither Mg2+ nor diamine putrescine produce concentrations similar those found bacterial cells. tetramer spermine, on other hand, not cells, strong condensation agent μ region. spermidine analog, bis-(3-aminopropyl)amine behavior role might play heads discussed.