ALIGNMENT AND PHYLOGENETIC ANALYSIS OF TYPE-II DNA TOPOISOMERASES

DNA topoisomerases have been evolved to solve the topological problems of DNA during replication, transcription, recombination and segregati on. Discovery of several new enzymes and their characterization has ne cessitated this compilation. This analysis shows the distinct evolutio nary relatedness of type II DNA topoisomerases. A striking feature is the absence of a contiguous stretch of about 160 amino acids in one of the subunits of prokaryotic type II enzymes, which might have importa nt implications to their structure and function.