Structural Basis for the Inverted Repeat Preferences of mariner Transposases.
Bottom Line: The inverted repeat (IR) sequences delimiting the left and right ends of many naturally active mariner DNA transposons are non-identical and have different affinities for their transposase.A 3.1 Å resolution crystal structure of the Mos1 paired-end complex containing the pre-cleaved left IR sequences reveals the molecular basis for the reduced affinity of the Mos1 transposase DNA-binding domain for the left IR as compared with the right IR.We find that this is due to the higher efficiency of cleavage and strand transfer of the preferred transposon end.
Affiliation: From the Institute of Cell Biology and.Show MeSH
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Mentions: To establish whether there is a preference for either the IRR or IRL sequence in the strand transfer step of the transposition reaction, we performed in vitro strand transfer assays using “pre-cleaved” Mos1 IRR or IRL DNA substrates, incorporating a fluorophore at the 5′ end of the 28-nt transferred strand for detection of 68- and 40-nt strand transfer products, as shown schematically in (Fig. 4A). We also performed the assay with Mboumar-9 IRR and IRL DNA substrates and Mboumar-9 transposase; in this case, strand transfer yields labeled products of 72 and 44 nt (Fig. 4A).