Comparative analysis of 18 sex pheromone plasmids from

Abstract

A new IS element, IS1062, related to the enterococcal IS elements IS6770 and IS1252, was detected in the 3'-terminus of the surface exclusion gene, sep1, of sex pheromone plasmid pPD1 in Enterococcus faecalis. pPD1-bearing cells lack the surface exclusion function, probably as a consequence of this insertion. Analysis of pAD1 and pPD1 sequences (7.5 kb and 2.7 kb, respectively) downstream of their aggregation substance genes revealed no similarity in these DNA regions. Detailed DNA/DNA hybridization studies using DNA probes specific for various pAD1-encoded genes needed for plasmid transfer indicated that the sex pheromone plasmids have evolved by repeated recombination and insertion of diverse transposable elements which presumably account for recent acquisition of antibiotic resistances.

Mutations in the carboxy‐terminal part of IS30 transposase affect the formation and dissolution of (IS30)2 dimer

“…The C‐terminal part of the Xba I* and Bgl II* IS 30 transposase mutants is shown below the wild‐type protein. The references for the presented amino acid sequences are the following: IS 1086 [18]; IS 1394 [19]; ISA 2 [20]; IS 4351 [21]; IS 1070 [22]; IS 1161 [23]; IS 1239 [24]; IS 6770 [25]; Spv1: ORF3 protein of the single‐stranded virus [26]; IS 1062 [27]; IS 30 [3]. The alignment was made by the GCG program package [28].…”