Figure 2.

Purification of phage N4 putative large and small terminases and the ATP-hydrolysis activity of the large terminase protein gp68. (a) Left: SDS polyacrylamide gel showing purified gp68 (62.7 kDa). Lane 1, pellet; lane 2, supernatant; lane 3, flowthrough; lane 4, protein marker (labelled in kDa); lane 5, eluate from Ni²⁺–NTA column; lane 6, eluate from Q HP column; lane 7, eluate from Superdex 200 16/300 pg column. Right: SDS polyacrylamide gel showing the purified gp69 (28 kDa). (b) Elution profile of gp68 and gp69 from a Superdex 200 16/300 pg column. The peak for gp68 at 69.2 ml corresponds to the monomeric form of gp68 (top profile) and the peak at 50.8 ml approximately represents the decameric form of gp69 (bottom profile) according to standard molecular-weight markers. (c) gp68 possesses ATP-hydrolysis activity that is further stimulated by the small terminase gp69. See §2 for details.