Role of the N-terminal domain of phiC31 integrase in attB-attP synapsis.

PhiC31 integrase is a serine recombinase containing an N-terminal domain (NTD) that provides catalytic activity and a large C-terminal domain that controls which pair of DNA substrates is able to synapse. We show here that substitutions in amino acid V129 in the NTD can lead to defects in synapsis and DNA cleavage, indicating that the NTD also has an important role in synapsis.