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This project aims to dissect the sequence-structure-specificity relationships of Lytic Polysaccharide MonoOxygenases (LPMOs). LPMOs, which are key enzymes in plant biomass conversion, are classified in families AA9-AA11 and AA13 in the CAZy database. Genes encoding AA9 LPMOs are often highly abundant in wood-degrading fungal species (>30), and this multiplicity suggests distinct functions (e.g. substrate specificity), likely to match the diversity and complexity of plant biomass. However, determinants of LPMO specificity remain unclear. During my PhD (carried out in collaboration with several international partners) I studied an AA9 LPMO from the filamentous fungi Lentinus similis (LsAA9A). Here the first LPMO-carbohydrate complex structures were presented providing insights into LPMO interactions with cellulose fragments, and revealed structural features accounting for the specificity. Other AA9 LPMOs appear to have similar functionality (inferred from structure and sequence), thus the project aims to establish sequence-structure-specificity relationships for AA9 LPMOs. Bioinformatic analysis of AA9s based on fungal proteomic data are carried out at the Architecture et Fonction des Macromolécules Biologiques (AFMB) and Biodiversity and Biotechnology of Fungi (BBF) laboratory using the tools of the CAZy database. At the BBF the selected AA9 targets are expressed in Pichia pastoris, purified using chromatographic methods and biochemical characterized and assayed on various carbohydrate substrates. Substrate specificities and product formation after enzymatic degradation are assessed and analysed with fluorometric methods, ionic chromatography (Dionex HPEAC-PAD) and mass spectrometry. Lastly, some of these AA9 members will be subjected to protein crystallization trials to further investigate structure-activity relationships.
I obtained my MSc and PhD degree from the Department of Chemistry; University of Copenhagen in the research section of Biological Chemistry using synchrotron radiation based X-ray crystallography as the primary method. During my MSc I studied the CI transcription factor of the lactococcal temperate bacteriophage TP901-1 involved in a genetic switch related to human pathogens (e.g. MRSA). My PhD project focused on structural characterization of Cu-containing enzymes, denoted LPMOs (Lytic Polysaccharide MonoOxygenases), important in biomass conversion. From the project came the first LPMO-carbohydrate complex structures published in first author publications in Nature Chemical Biology and Nature Communications, which I presented during an oral presentation at the 19th European Carbohydrate Symposium (EUROCARB 2017) 2-6 July 2017 in Barcelona. Since May 2017 I have been doing biochemical characterization of AA9 LPMOs in the BBF lab (Biodiversity and Biotechnology of Fungi) under Senior Scientist Jean-Guy Berrin at INRA, Aix-Marseille Université. My AgreenSkills fellowship is co-funded by the Carlsberg Foundation through Internationalisation Postdoc Fellowship grants from 2017 to 2019.
Frandsen, K.E.H., Simmons, T.J., Dupree, P., et al., 2016. The molecular basis of polysaccharide cleavage by lytic polysaccharide monooxygenases. Nat. Chem. Biol. 12, 298-303.
Simmons, T.J.*, Frandsen, K.E.H.*, Ciano, L., Tryfona, T., Lenfant, N., Poulsen, J-C., Wilson, L.F.L., Tandrup, T., Tovborg, M., Schnorr, K., Johansen, K.S., Henrissat, B., Walton, P. H., Lo Leggio, L., and Dupree, P., 2017. Structural and electronic determinants of lytic polysaccharide monooxygenase reactivity on polysaccharide substrates. Nat. Commun. 8:1064. Doi:10.1038/s41467-017-01247-3.
Frandsen K.E. & Lo Leggio, L., 2016. Lytic polysaccharide monooxygenases - a crystallographer’s view on a new class of biomass degrading enzymes. IUCrJ 3, 448-467.
Lo Leggio, L., Simmons, T.J., Poulsen, JC., Frandsen, K.E., Hemsworth, G.R., Stringer, M.A., von Freiesleben, P., Tovborg, M., Johansen, K.S., De Maria, L., Harris, P.V., Soong, C.L., Dupree, P., Tryfona, T., Lenfant, N., Henrissat, B., Davies, G.J., Walton, P.H., 2015. Structure and boosting activity of a starch-degrading lytic polysaccharide monooxygenase. Nat. Commun. 6; 5961. Doi:10.1038/ncomms6961.
Couturier, M.*, Ladevèze, S.*, Sulzenbacher, G., Ciano, L., Fanuel, M., Moreau, C., Villares, A., Cathala, B., Chaspoul, F., Frandsen, K.E., ..., Berrin, J-G., 2018. Lytic xylan oxidases from wood-decay fungi unlock biomass degradation. Nat. Chem. Biol. 14, 306-310.
* Equally contributing authors
Carlsberg Foundation Internationalisation Fellowship (Postdoctoral grant for outstanding PhDs for a 12-month stay at a leading international research institution). Grant CF17-0533 of DKK 425.000 (equivalent of € 57.000)
Carlsberg Foundation Internationalisation Fellowship (Postdoctoral grant for outstanding PhDs for a 12-month stay at a leading international research institution). Grant CF16-0673 of DKK 350.000 (equivalent of € 47.000)
Top 3 candidate for the MAX IV Best PhD Thesis Award 2017
2nd Prize of Poster Session I at 11th Carbohydrate Bioengineering Meeting (CBM11)