Bacteroides fragilis Synthesizes a DNA Invertase Affecting both a Local and a Distant Region

Abstract
The activity of a fourth conserved tyrosine site-specific recombinase (Tsr) of Bacteroides fragilis was characterized. Its gene, tsr19 , is adjacent to mpi , encoding the global DNA invertase regulating capsular polysaccharide biosynthesis. Unlike the other described Tsrs of B. fragilis , Tsr19 brings about inversion of two DNA regions, one local and one located distantly.