Types of Topoisomerases

Type I: Breaks one strand of DNA, pass the other strand through the gap and seal the break. L = +/- 1 (in E.coli= relaxes -ve supercoil). Type II: break both strands of the DNA, pass another part of the helix through the gap and change the L by +/- 2 (in E.coli= DNa gyrase creates -ve supercoils).