摘要: The dinucleotide CA found at the termini of transposable phage Mu also occurs a large class elements, including HIV, all retroviruses and many retrotransposons. In order to understand importance this sequence conservation, activity 16 permutations was first examined using sensitive plasmid-based in vivo transposition assay. reactivity these substrates varied over several orders magnitude vivo, with substitutions A position being more severely impaired than those C position. same general hierarchy observed vitro mutant oligonucleotide substrates. These experiments revealed that not important for chemistry strand transfer, block stage assembly stable transpososome. Given DNA Mu-host junctions is melted/distorted concomitantly transpososome assembly, we consider hypothesis has been selected transposon primarily its significant conformational mobility.