Other TE encode transposases which resemble serine site-specific
recombinases. Their chemistry is presumably similar to that of their
sequence-specific recombinase cousins.
IS607 family members
encode a Tpase closely resembling serine site-specific recombinases which use
serine as a nucleophile for cleavage of the DNA strand (Grindley, 2002). At present little is known about transposition of
this IS family although it is thought that these elements generate circular
intermediates (NDF Grindley pers. comm. cited in (Filee, et al., 2007)).
Presumably the enzyme catalyses similar cleavages and strand transfers as its
site-specific serine recombinase cousins using a transitory 5' phosphoserine
covalent intermediate. Based on transposase structures from structural genomics
studies and detailed knowledge of the general serine recombinase mechanism, (Boocock & Rice, 2013) have proposed a
model for the transposition mechanism. This includes a synaptic transposase
tetramer (as for classical serine recombinases). The model explains the lack of
target specificity exhibited in IS607 transposition (Kersulyte, et al., 2000), behaviour which is unusual for this type of
MR & Rice PA (2013) A proposed mechanism for IS607-family serine
transposases. Mob DNA 4: 24.
J, Siguier P & Chandler M (2007) Insertion sequence diversity in archaea. Microbiol Mol Biol Rev 71: 121-157.
NDF (2002) The movement of Tn3-like elements: transposition and cointegrate
resolution. Mobile DNA II,(Craig NL,
Craigie R, Gellert M & Lambowitz A, eds.), pp. 230-271. ASM press,
- Kersulyte D, Mukhopadhyay AK, Shirai
M, Nakazawa T & Berg DE (2000) Functional organization and insertion
specificity of IS607, a chimeric element of Helicobacter pylori. J Bacteriol 182: 5300-5308.