The integrases are a family of proteins that recombine DNA duplexes by executing two consecutive strand breakage and rejoining steps and a topoisomerization of the reactants ( 1, 2). In addition, these results offer clues into an apparent discrepancy between the mechanisms of different subfamilies of integrases. It was also possible to map the location of conserved residues onto the available crystal structures most of the conserved residues cluster in the predicted active site cleft. This analysis showed that members of the family aggregate into subfamilies which are consistent with their biological roles these subfamilies have significant levels of sequence similarity beyond the four residues previously identified. Alignment and comparisons of these sequences combined with an evolutionary analysis aided in identifying broader sequence similarities and clarifying the possible functions of these conserved residues. We have now identified a total of 81 members of the integrase family deposited in the databases. However, few additional sequence similarities were found in the original group of 27 proteins. Members of this family, of which the well-studied lambda Int protein is the prototype, were previously found to share four strongly conserved residues, including an active site tyrosine directly involved in transesterification.

The integrases are a diverse family of tyrosine recombinases which rearrange DNA duplexes by means of conservative site-specific recombination reactions.

Macvector recombination