The DEDD enzymes

DEDD enzymes are limited to transposases of the IS110 family at present (Tobiason, et al., 2001) and closely related to the Piv and MooV invertases from Moraxella lacunata/M. bovis (Fulks, et al., 1990, Rozsa, et al., 1997) and N. gonorrhoeae (Choi, et al., 2003, Skaar, et al., 2005) respectively. Piv catalyses inversion of a DNA segment permitting expression of a type IV pilin. However, the organization of IS110 family members and the inversion systems are different. In the IS, the recombinase is located within the element whereas in the inversion systems it is located outside the invertible segment (Buchner, et al., 2005).

Although it has proved difficult to determine the activity of these transposases in detail in vitro, transposition of ISs with DEDD Tpases may be unusual and involve HJ intermediates which must be resolved using a RuvC-like mechanism. This type of recombination would be consistent with the close relationship between DEDD transposases and the Piv/MooV invertases which presumably resolve HJ structures during inversion (Tobiason, et al., 1999).

References :

• Buchner JM, Robertson AE, Poynter DJ, Denniston SS & Karls AC (2005) Piv Site-Specific Invertase Requires a DEDD Motif Analogous to the Catalytic Center of the RuvC Holliday Junction Resolvases. 10.1128/JB.187.10.3431-3437.2005. J. Bacteriol. 187: 3431-3437.
• Choi S, Ohta S & Ohtsubo E (2003) A novel IS element, IS621, of the IS110/IS492 family transposes to a specific site in repetitive extragenic palindromic sequences in Escherichia coli. J Bacteriol 185: 4891-4900.
• Fulks KA, Marrs CF, Stevens SP & Green MR (1990) Sequence analysis of the inversion region containing the pilin genes of Moraxella bovis. J Bacteriol 172: 310-316.
• Rozsa FW, Meyer TF & Fussenegger M (1997) Inversion of Moraxella lacunata type 4 pilin gene sequences by a Neisseria gonorrhoeae site-specific recombinase. J Bacteriol 179: 2382-2388.
• Skaar EP, Lecuyer B, Lenich AG, Lazio MP, Perkins-Balding D, Seifert HS & Karls AC (2005) Analysis of the Piv recombinase-related gene family of Neisseria gonorrhoeae. J Bacteriol 187: 1276-1286.
• Tobiason DM, Lenich AG & Glasgow AC (1999) Multiple DNA binding activities of the novel site-specific recombinase, Piv, from Moraxella lacunata. J Biol Chem 274: 9698-9706.
• Tobiason DM, Buchner JM, Thiel WH, Gernert KM & Karls AC (2001) Conserved amino acid motifs from the novel Piv/MooV family of transposases and site-specific recombinases are required for catalysis of DNA inversion by Piv. Mol.Microbiol. 39: 641-651.