RETROVIRAL INTEGRASES AND THEIR COUSINS

The recently determined structures of the catalytic domains of HIV int egrase, avian sarcoma virus integrase and the Mu transposase are strik ingly similar to each other and also exhibit significant similarity to several nucleases. All these enzymes cut polynucleotides, leaving 3'O H and 5'PO4 groups. The integrase and transposase also possess a stran d-transfer activity that splices DNA. The structural similarities amon g members of this superfamily of polynucleotidyl transferases suggest that they share a similar mechanism of catalysis.