title: The role of bivalent ions in the inactivation of bacteriophage phi X174 by lipopolysaccharide from Escherichia coli C.
abstract: The need for Ca2+ in the inactivation of bacteriophage phi X174 by lipopolysaccharide from Escherichia coli C was confirmed. Ca2+ could be replaced almost completely by Na+, but the concentration of Na+ needed was greater by more than an order of magnitude. Other bivalent ions caused inactivation in the same way as Ca2+, and the degree of inactivation varied according to the ion. At 50% inactivation of bacteriophage, the relation between the concentrations of NaCl and of bivalent or tervalent ions (Mx+) fitted the conception that NaCl was neutralizing electrostatic repulsion between virus and lipopolysaccharide by an ionic-strength effect: that is, log[Mx+] varies inversely with square root[NaCl]. The variation in effect of bi- and ter-valent ions and the low concentration needed show that this is not an ionic-strength effect but likely to involve binding to more than one site.
mesh_terms: D010584:Bacteriophage phi X 174 / Q000187:drug effects*; D001665:Binding Sites; D002118:Calcium / Q000494:pharmacology; D002413:Cations, Divalent / Q000494:pharmacology*; D004926:Escherichia coli; D007700:Kinetics; D008070:Lipopolysaccharides / Q000494:pharmacology*; D009994:Osmolar Concentration; D012964:Sodium / Q000494:pharmacology
chemical_list: D002413:Cations, Divalent; D008070:Lipopolysaccharides; D012964:Sodium; D002118:Calcium