Patent ID: 11965183
Assignee: OXFORD NANOPORE TECHNOLOGIES PLC
Field: Biotechnology (Chemistry)
Classification: CPC C | IPC C

Claim 0:
1. A method of characterising a target polynucleotide, comprising:
(a) contacting the target polynucleotide with a transmembrane pore and a helicase such that the helicase controls the movement of the target polynucleotide through the pore; and
(b) taking one or more electrical measurements as the polynucleotide moves with respect to the pore wherein the measurements are indicative of one or more characteristics of the target polynucleotide and thereby characterising the target polynucleotide,
wherein the helicase is a DNA-dependent ATPase (Dda) helicase in which:
(i) the Dda helicase comprises a sequence that is at least 70% identical to the sequence set forth in SEQ ID NO: 8 and is recombinantly substituted in at least one residue corresponding to at least one of the following amino acid positions in SEQ ID NO: 8 which interacts with one or more nucleotides in single stranded DNA (ssDNA): H82, N88, P89, F98, D121, V150, P152, F240, F276, S287, H396 and/or Y415; and
(ii) the part of the Dda helicase which interacts with the transmembrane pore comprises one or more modifications at one or more residues corresponding to a position in SEQ ID NO: 8 selected from the group consisting of: 3, 4, 5, 176, 177, 179, 180, 185, 193, 194, 195, 198, 199, 200, 202, 203, 204, 207, 208, 209, 210, 211, 212, 213, 216, 221, 224, 255, 318, 347, 405, 415, 434, 437, and 438.