Serine Recombinase family, catalytic domain; a DNA binding domain may be present either N- or C-terminal to the catalytic domain. These enzymes perform site-specific recombination of DNA molecules by a concerted, four-strand cleavage and rejoining mechanism which involves a transient phosphoserine linkage between DNA and serine recombinase. Serine recombinases demonstrate functional versatility and include resolvases, invertases, integrases, and transposases. Resolvases and invertases (i.e. Tn3, gamma-delta, Tn5044 resolvases, Gin and Hin invertases) in this family contain a C-terminal DNA binding domain and comprise a major phylogenic group. Also included are phage- and bacterial-encoded recombinases such as phiC31 integrase, SpoIVCA excisionase, and Tn4451 TnpX transposase. These integrases and transposases have larger C-terminal domains compared to resolvases/invertases and are referred to as large serine recombinases. Also belonging to this family are proteins with N-terminal DNA binding domains similar to IS607- and IS1535-transposases from Helicobacter and Mycobacterium.
Structure:1ZR4; Escherichia coli Synaptic Gamma-Delta Resolvase forms a phosphoserine linkage to the 5' end of cleaved DNA
Comment:When cleavage occurs, a phosphodiester bond is replaced by a phosphoserine bond between a 5' phosphate group at the DNA cleavage site and a Ser hydroxyl group of the resolvase.
Jiyao W et al.(2023). "The conserved domain database in 2023.",