[Inversion activity in the resolution of transposons Tn5053 and Tn402 possessing a nonstandardly organized res-region].

The classical bacterial site-specific systems of DNA resolution are characterized, despite their considerable divergence, by a regularly arranged res region represented as a triad of res sites. DNA resolution (deletion) is carried out more efficiently than DNA inversion, primarily due to this structure. In this report, the ratio of deletion to inversion activities is evaluated for the resolution systems of Tn5053 and Tn402, which belong to a novel family and possess an irregularly arranged res region. By this criterion, the system studied is shown to be similar to the classical ones. These data suggest that in the course of evolution of the resolvase systems, the same degree of recombination specialization could be attained by different arrangement of the res region.