Stimulation of the Mu A protein-mediated strand cleavage reaction by the Mu B protein, and the requirement of DNA nicking for stable type 1 transpososome formation. In vitro transposition characteristics of mini-Mu plasmids carrying terminal base pair mutations.

We have examined the effects of a T----C point mutation at the terminal nucleotide of the Mu ends in a mini-Mu plasmid on the early steps in the in vitro transposition reaction. These mutations inhibit the introduction of nicks at the Mu ends in a reaction with Mu A, HU, and integration host factor proteins. The presence of the point mutation at either the left end or the right end is sufficient to block the nicking reaction at both ends, …