Purification and Molecular Properties of a New Colicin

Open Access
Publisher Website
Google Scholar
Abstract
The process of isolation and purification of a new colicin isolated from a Citrohacter strain is described. Escherichia coli sensitive cells are protected by vitamin B12 from the action of this bacteriocin; this suggests that it belongs to the E group of colicins. Therefore, we have called it colicin E4. It has a molecular weight of 56000 and two molecular forms of isoelectric points 9.4 and 8.2 are separated in electrofocusing on polyacrylamide gels. It has a sedimentation coefficient of 3.4 S and the absorption coefficient A1280% is 6.23 cm−1. Using an antibody raised against pure colicin E4, no cross‐reaction was detected against colicins A, E1 or K. The physiological effect of colicin E4 on sensitive cells is very similar to that of colicins El, K or I which disrupt the energized membrane state.