MECHANISM OF COMPETENCE IN TRANSFORMATION OF STREPTOCOCCI OF SEROLOGICAL GROUP H - PURIFICATION AND SOME PROPERTIES OF COMPETENCE FACTOR

In Streptococcus challis, similarly as in the other transforming systems, the appearance of competence (i.e. the ability to take up DNA and undergo transformation) is strictly related to the production by the cells of a special competence factor (CF). As we reported previously, S. challis CF or an essential fragment of its seems to be a polypeptide. In the present work, the method of the purification of S. challis CF on CM-cellulose is described. Highly purified (O.D. at 280 mμ-0,05-0.1) freeze-dried preparations of this factor were obtained. The results of chromatography on Sephadex and Bio-Gels columns suggest, that the mol. w. of the S. challis CF is about 5,000. Highly purified preparations of the CF, besides the competence inducing activity, contain a factor (s) which inactivates transforming DNA in vitro and appears to include some DNase-like activity. © 1969 Springer-Verlag.