1H, 15N and 13C backbone resonance assignments of flap endonuclease from Plasmodium falciparum

Flap endonuclease (FEN) enzymes are a group of metallonucleases that have essential roles in DNA repair and the maintenance of genomic resilience. They catalyse hydrolytic cleavage of a phosphodiester bond to remove 5'-flaps present on double-stranded DNA molecules formed during DNA replication. FEN locates a target scissile bond through the structural recognition of a pronounced bend in the double-stranded DNA substrate along with the presence of both a 5'-flap and a 1-nucleotide 3'-flap. FEN enzymes share a common structural architecture and are functionally conserved across all living organisms. In this work, we report the ¹H, ¹⁵N and ¹³C backbone resonance assignments of residues 2-349 of FEN from Plasmodium falciparum (PfFEN349) in its substrate-free state. Using heteronuclear multidimensional NMR spectroscopy, 90% of all backbone resonances of PfFEN349 were assigned, with 298 backbone amide resonances out of 337 theoretically-detectible resonances (which exclude 10 prolines and the N-terminal glycine) identified in the ¹H-¹⁵ N TROSY spectrum. Prediction of solution secondary structure content from a chemical shift analysis using the TALOS-N webserver is mostly in good agreement with an AlphaFold model of PfFEN349. The reported assignments provide a pathway for drug discovery as PfFEN349 is a potential target for the development of new inhibitors that could be utilised to control the incidence of malaria across the globe.