Biophysics of T5, IRA phages, Escherichia coli outer membrane protein FhuA and T5-FhuA interaction

In spite of the similarities in a structural organization of T5 and IRA phages their thermal and hydrodynamical peculiarities are completely different. One of the significant differences is observed in temperature value at which thermally induced DNA ejection starts. If in the case of physiological conditions this difference equals to 30 degrees capital ES, Cyrillic, then it decreases as ionic strength of the solvent decreases. Also, from our experimental results follows that in the opening of phage tail channel for T5 phage (at pH7) significant role-play electrostatic forces. In spite of that both of these phages grow on the same Escherichia coli strain, we have shown that these phages need different receptors to penetrate into the bacterial cell precisely FhuA serves as receptor only for T5 phage. The higher FhuA concentration in T5 phage suspension is, the more intensive DNA ejection in environment is. The minimal FhuA/T5 ratio, which is 300/1, correspondingly, necessary for effective DNA ejection from the phage head was experimentally determined. For the first time the ejection of T5 phage DNA induced by FhuA was observed in an incessant regime. The deconvolution of calorimetric curve of FhuA's denaturation has been shown that in a chosen condition there are four thermodynamically independent domains in the structure of FhuA.