Interaction between phage G13 and its oligosaccharide receptor studied by equilibrium dialysis
✍ Scribed by Gert W. Bruse; Ralfh Wollin; Alf A. Lindberg
- Publisher
- John Wiley and Sons
- Year
- 1989
- Tongue
- English
- Weight
- 707 KB
- Volume
- 2
- Category
- Article
- ISSN
- 0952-3499
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✦ Synopsis
The reversible binding of phage G13, a gX174-like single-strand DNA phage, to a 3H-labelled nonasaccharide from the lipopolysaccharide of its natural host Escherichia coli C was studied with equilibrium dialysis. The binding constant (K.)
was determined to 1.3 x lo7 M -' in Scatchard and Lineweaver-Burk plots. Approximately one saccharide bound per G13 phage particle which suggests that only one of the 12 spikes in each G13 virion was engaged in the phage/receptor saccharide interaction. Equilibrium dialysis inhibition experiments with saccharides from lipopolysaccharides of an isogenic series of Salmonella ryphimurium mutants showed that hepta-and pentasaccharides from two G13-sensitive bacteria, i.e., with efficiencies of plating of 0.1-1.0 compared to E. coli C, were efficient inhibitors with K.-values 2 1.2 x lo7 M-'. The octa-and hexasaccharides from two G13 resistant strains, with efficiency of plating G x were either > 1000-fold or > 15-fold less efficient as inhibitors with K.-values G8.8 x 105 M -I. The results show that phage G13 binds in a specific and reversible way to penta-, hepta-, and nonasaccharides from G13 sensitive bacteria with the specificity residing in the hexose and heptose region of the core lipopolysaccharide.