Method for modifying a template double stranded polynucleotide

1. A method for modifying a template double stranded polynucleotide, comprising:

(a) contacting the template polynucleotide with a MuA transposase and a population of double stranded MuA substrates each comprising an overhang at one or both ends of one strand such that the transposase fragments the template polynucleotide and ligates a substrate to one or both ends of the double stranded fragments and thereby producing a plurality of fragment/substrate constructs; and

(b) using a translocase to remove the MuA transposases from the constructs and thereby producing a plurality of modified double stranded polynucleotides.

2. The method according to claim 1 , wherein the translocase is contacted with the constructs after they are created by the MuA transposase.

3. The method according to claim 1 , wherein the translocase is bound to the substrates before the substrates are contacted with the template polynucleotide.

4. The method according to claim 1 , wherein the translocase is a helicase.

5. The method according to claim 1 , wherein the translocase is a helicase is from superfamily 1 or superfamily 2.

6. The method according to claim 5 , wherein the helicase is a member of one of the following families: Pif1-like, Upf1-like, UvrD/Rep, Ski-like, Rad3/XPD, NS3/NPH-II, DEAD, DEAH/RHA, RecG-like, REcQ-like, T1R-like, Swi/Snf-like, and Rig-I-like.

7. The method according to claim 5 , wherein the helicase is a UvrD helicase, a Hel308 helicase, a Tral helicase, a Tral subgroup helicase, an XPD helicase, or a Dda helicase.

8. The method according to claim 1 , wherein the translocase is a Hel308 helicase.

9. The method according to claim 1 , wherein the translocase is a Hel308 helicase and is Hel308 Mbu (E284C/S615C)-bismaleimidePEG11 (SEQ ID NO: 10 with mutations E284C/S615C connected by a bismaleimidePEG11 linker).

10. The method according to claim 1 , wherein the translocase is a strippase.

11. The method according to claim 10 , wherein the strippase is the INO80 chromatin remodeling complex or a FtsK/SpoIIIE transporter.

12. The method according to claim 1 , wherein the method further comprises attaching molecular brakes to the other strands in the substrates.

13. The method according to claim 1 , wherein the method further comprises attaching molecular brakes to the other strands in the substrates and wherein the molecular brakes are attached to the other strands in the substrates before they are contacted with the template polynucleotide and the MuA transposase.

14. The method according to claim 1 , wherein the method further comprises attaching molecular brakes to the other strands in the substrates and wherein the molecular brakes are attached to the other strands from the substrates remaining in the constructs after they are created by the MuA transposase.

15. The method according to claim 1 , wherein the method further comprises attaching molecular brakes to the other strands in the substrates and wherein the molecular brakes are bound to Y adaptors comprising a leader sequence and/or one or more anchors capable of coupling the adaptor to a membrane and the Y adaptors are attached to the other strands in step (c).

16. The method according to claim 1 , wherein the method further comprises attaching molecular brakes to the other strands in the substrates and wherein the molecular brakes are derived from a polymerase, a helicase or an exonuclease.

17. The method according to claim 1 , wherein the method does not comprise heat inactivating the MuA transposase.

18. A plurality of polynucleotides modified using the method according to claim 1 .

19. The method of characterising at least one polynucleotide modified using a method according to claim 1 , comprising:

a) contacting the modified polynucleotide with a transmembrane pore such that at least one strand of the polynucleotide moves through the pore; and

b) taking one or more measurements which are indicative of one or more characteristics of the polynucleotide as the at least one strand moves with respect to the pore and thereby characterising the modified polynucleotide.

20. A method of characterising a template polynucleotide, comprising:

a) modifying the template polynucleotide using the method according to claim 1 to produce a plurality of modified polynucleotides;

b) contacting each modified polynucleotide with a transmembrane pore such that at least one strand of each polynucleotide moves through the pore; and

c) taking one or more measurements which are indicative of one or more characteristics of the polynucleotide as the at least one strand of each polynucleotide moves with respect to the pore and thereby characterising the template polynucleotide.