Reptation of DNA from bacteriophage

The kinetics of the reptation process of release of bihelical DNA from the phage head is theoretically analysed. It is assumed that the driving force of the process is decrease in the free energy of DNA on release from the head where it must be in the globular state into the surrounding medium where it unfolds into a coil. For the analysis the authors use the results of previous work on the equilibrium theory of the intraphage globule of DNA. Three possible sources of friction are considered in the ejection-friction process in the channel of the tail process: friction of the DNA segments against each other in the whole volume of the globule, which is important in the collective mechanism of decondensation of the globule with simultaneous movement of all the turns (mechanism 1); friction of the globule against the inner surface of the capsid, which is most important in the mechanism of decondensation through rotation of the globule as a whole "spool" (mechanism 2). From the published experimental data on the difference in the kinetics of ejection for phages with short and long tail processes a conclusion is drawn in favour of the realization in nature of mechanism 2; mechanism 1 would correspond to the longest ejection time.