<p>This transposase is essential for integration, replication-transposition and excision of <taxon tax_id="10677">Bacteriophage Mu</taxon> DNA. Transposition requires transposase and a transposition enhancer, and the DNA can be transposed into multiple sites in bacterial genomes.</p><p>The crystal structure of the core domain of Mu transposase, MuA, has been determined. The first of two subdomains contains the active site and, despite very limited sequence homology, exhibits a striking similarity to the core domain of <taxon tax_id="11676">Human immunodeficiency virus 1</taxon> integrase. The enzymatic activity of MuA is known to be activated by formation of a DNA-bound tetramer of the protein [<cite idref="PUB00007414"/>].</p><p>More information about these proteins can be found at Protein of the Month: Transposase [<cite idref="PUB00034633"/>].</p>