Background and activities
I am a PostDoc financed by a personal grant from the Novo Nordisk Foundation. The project consists of studying multi-domain lytic polysaccharide monooxgyenases with NMR spectroscopy, simulations, and other biophysical (e.g. SAXS) and biochemical techniques to understand the interplay between the folded domains and the role of unstructured linker regions.
I am a part of the Biopolymer NMR research group at the Norwegian Biopolymer Laboratory (NOBIPOL).
My main research interest is the use NMR spectroscopy, MD simulations and biochemistry techniques to study the structures and functions of enzymes. Currently, I am involved in the following activities.
1. Felxible protein linkers
Project: LinkD - Novo Nordisk Foundation
Linkers are intinsically disordered regions of proteins. Linkers of varying flexibility keep multiple domains in proteins joined together. Depending on their sequence and length, linkers may increase or decrease the number of contacts between the thethered domains . Therefore, linkers have important roles in regulating the function of the enzyme domains they are attached to .
In collaboration with Prof. Kresten Lindorff-Larsen at the University of Copenhagen, we are using an integrative modelling approach  to study the function of linker in LPMOs. We perform MD simulations to generate conformational ensembles that are then validated with small-angle X-ray scattering (SAXS) and NMR spectroscopy (secondary chemical shift, diffusion) data to produce models of multi-modular enzymes.
2. Efficient enzyme production systems
Project: OXYMOD - Digital Life Norway/Research Council of Norway
Producing sufficient amounts (>1 g/L of culture) of pure, correctly folded enzymes is a pre-requirement for all biochemical investigations. Heterologous expression in E. coli is the most straight-forward way to produce enzymes. However, protein expression when using glucose as the sole carbon source, for example for 13C enrichment, often leads to low yields as a result of catabolite repression of promoters based on the carbon metabolism of E. coli, such as Plac.
We have circumvented this problem by constructing an expression system for LPMOs based on the Pm/XylS promotor/activator system , in collaboration with Prof. Trygve Brautaset. In cooperation with SINTEF Industry, we were able to demonstrate the system’s usability in high-cell density cultivations, leading to very high protein yields in bioreactors.
3. LPMOs (lytic polysaccharide monooxygeneases) and CBMs (carbohydrate-binding modules)
Project: OXYMOD - Digital Life Norway/Research Council of Norway
LPMOs are copper-dependant enzymes that degrade carbohydrates through an oxidative mechanism [5–7]. The LPMO reaction involves the reduction of Cu(II) to Cu(I) in the active site by an electron donor that can either be another redox protein or small-molecule reductants . After this initial reduction, the copper site activates either O2  or H2O2 . LPMOs use this activated oxygen species to oxidize carbohydrates, making tightly-bound polysaccharides like cellulose and chitin available to other enzymes [11, 12] like glycoside hydrolases, which convert polysaccharides to sugar. These products can then be fermented into bioethanol or converetd to high value-added products . In addition to these polysaccharides, LPMOs have been shown to be active on a wide variety of carbohydrates such as amylose and hemicellulose. Moreover, CBMs  tethered to LPMOs through peptide linkers confer different substrate binding possibilities.
Overall, LPMOs are important factors in enabling the green shift from an oil-based to a sustainable society. To achieve this, a better understanding of their mode of action is needed. I started working on LPMOs in 2012 during my Master’s, and continued working with them as the main focus of my PhD (2014-2018). Through various collaborations, we have been able to gain valuable insights into LPMO functionality, such as:
- Insights into the three-dimensional structure of LPMOs, including the effect of copper on the overall structure and active site conformation.
- Structure-function relationships between LPMO structure and binding specificity to different substrates.
- Interactions with redox partner enzymes.
- Combining experiments and simulations to study substrate binding of CBM domains attached to LPMOs.
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2. B. Ma, C. J. Tsai, T. Haliloglu, R. Nussinov, Structure 19, 907–917 (2011). https://doi.org/10.1016/j.str.2011.06.002
3. S. Bottaro, K. Lindorff-larsen, Science 361, 355–360 (2018). https://doi.org/10.1126/science.aat4010
4. Courtade G., Balzer S. L., Sætrom G. I., Brautaset T., Aachmann F. L.. A novel expression system, Carbohydrate Research 448, 212–219 (2017) https://doi.org/10.1016/j.carres.2017.02.003
5. G. Vaaje-Kolstad, S. J. Horn, D. M. F. van Aalten, B. Synstad, V. G. H. Eijsink, JBC 280, 28492–28497 (2005). https://doi.org/10.1074/jbc.M504468200
6. G. Vaaje-Kolstad et al., Science 330, 219–222 (2010). https://doi.org/10.1126/science.1192231
7. R. J. Quinlan et al., PNAS 108, 15079–15084 (2011). https://doi.org/10.1073/pnas.1105776108
8. D. Kracher et al., Science 352, 1098–1101 (2016). https://doi.org/10.1126/science.aaf3165
9. P. H. Walton, G. J. Davies, Current Opinion in Chemical Biology 31, 195–207 (2016). https://doi.org/10.1016/j.cbpa.2016.04.001
10. B. Bissaro et al., Nature Chemical Biology 13, 1123–1128 (2017). https://doi.org/10.1038/nchembio.2470
11. S. J. Horn, G. Vaaje-Kolstad, B. Westereng, V. G. H. Eijsink, Biotechnology for Biofuels 5, 45 (2012). https://doi.org/10.1186/1754-6834-5-45
12. Z. Forsberg et al., Protein Science 20, 1479–1483 (2011). https://doi.org/10.1002/pro.689
13. K. S. Johansen, Biochemical Society Transactions 44, 143–149 (2016). https://doi.org/10.1042/bst20150204
14. A. B. Boraston, D. N. Bolam, H. J. Gilbert, G. J. Davies, Biochem. J 382, 769–781 (2004). http://doi.org/10.1042/bj20040892
Scientific, academic and artistic work
Displaying a selection of activities. See all publications in the database
- (2020) 1H, 13C, 15N resonance assignment of the apo form of the small, chitin-active lytic polysaccharide monooxygenase JdLPMO10Afrom Jonesia denitrificans. Biomolecular NMR Assignments.
- (2020) Mechanistic basis of substrate–O2 coupling within a chitin-active lytic polysaccharide monooxygenase: An integrated NMR/EPR study. Proceedings of the National Academy of Sciences of the United States of America. vol. 117 (32).
- (2020) Class IV lasso peptides synergistically induce proliferation of cancer cells and sensitize them to doxorubicin. iScience. vol. 23 (12).
- (2019) Polysaccharide degradation by lytic polysaccharide monooxygenases. Current Opinion in Structural Biology. vol. 59.
- (2018) The carbohydrate-binding module and linker of a modular lytic polysaccharide monooxygenase promote localized cellulose oxidation. Journal of Biological Chemistry. vol. 293 (34).
- (2018) Resonance assignments for the apo-form of the cellulose-active lytic polysaccharide monooxygenase TaLPMO9A. Biomolecular NMR Assignments. vol. 12 (2).
- (2018) Methylation of the N-terminal histidine protects a lytic polysaccharide monooxygenase from auto-oxidative inactivation. Protein Science. vol. 27 (9).
- (2017) Chemical shift assignments for the apo-form of the catalytic domain, the linker region, and the carbohydrate-binding domain of the cellulose-active lytic polysaccharide monooxygenase ScLPMO10C. Biomolecular NMR Assignments. vol. 11 (2).
- (2017) A novel expression system for lytic polysaccharide monooxygenases. Carbohydrate Research. vol. 448.
- (2017) Human Chitotriosidase: Catalytic Domain or Carbohydrate Binding Module, Who’s Leading HCHT’s Biological Function. Scientific Reports. vol. 7 (1).
- (2016) Backbone and side-chain 1H, 13C, and 15N chemical shift assignments for the apo-form of the lytic polysaccharide monooxygenase NcLPMO9C. Biomolecular NMR Assignments. vol. 10 (2).
- (2016) Interactions of a fungal lytic polysaccharide monooxygenase with β-glucan substrates and cellobiose dehydrogenase. Proceedings of the National Academy of Sciences of the United States of America. vol. 113 (21).
- (2015) 1H, 13C, 15N resonance assignment of the chitin-active lytic polysaccharide monooxygenase BlLPMO10A from Bacillus licheniformis. Biomolecular NMR Assignments. vol. 9 (1).
- (2013) Experimental and theoretical investigation of drotaverine binding to bovine serum albumin. Biotechnology and Food Science. vol. 77 (1).
Part of book/report
- (2019) Chitin-Active Lytic Polysaccharide Monooxygenases. Targeting Chitin-containing Organisms.
- (2018) An NMR investigation of lytic polysaccharide monooxygenases. 2018. ISBN 978-82-326-3462-0. Doktoravhandlinger ved NTNU (337).
- (2014) Structural Investigation of a Lytic Polysaccharide Monooxygenase by NMR Spectroscopy. 2014.