| Author |
Wimmer, Reinhard Sandgren, Mats Felice, Alfons K. G. Røhr, Åsmund K. Sørlie, Morten Preims, Marita Aachmann, Finn Lillelund Dimarogona, Maria Courtade, Gaston Vaaje-kolstad, Gustav Ludwig, Roland Eijsink, Vincent G. H. |
| Description |
Author Affiliation: Courtade G ( Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway); Wimmer R ( Department of Chemistry and Bioscience, Aalborg University, DK-9220 Aalborg Ø, Denmark); Røhr ÅK ( Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway); Preims M ( Food Biotechnology Laboratory, Department of Food Science and Technology, Vienna Institute of Biotechnology, University of Natural Resources and Life Sciences, Vienna A-1190, Austria); Felice AK ( Food Biotechnology Laboratory, Department of Food Science and Technology, Vienna Institute of Biotechnology, University of Natural Resources and Life Sciences, Vienna A-1190, Austria); Dimarogona M ( Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden.); Vaaje-Kolstad G ( Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway); Sørlie M ( Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway); Sandgren M ( Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden.); Ludwig R ( Food Biotechnology Laboratory, Department of Food Science and Technology, Vienna Institute of Biotechnology, University of Natural Resources and Life Sciences, Vienna A-1190, Austria); Eijsink VG ( Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway); Aachmann FL ( Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway); |
| Abstract |
Lytic polysaccharide monooxygenases (LPMOs) are copper-dependent enzymes that catalyze oxidative cleavage of glycosidic bonds using molecular oxygen and an external electron donor. We have used NMR and isothermal titration calorimetry (ITC) to study the interactions of a broad-specificity fungal LPMO, NcLPMO9C, with various substrates and with cellobiose dehydrogenase (CDH), a known natural supplier of electrons. The NMR studies revealed interactions with cellohexaose that center around the copper site. NMR studies with xyloglucans, i.e., branched β-glucans, showed an extended binding surface compared with cellohexaose, whereas ITC experiments showed slightly higher affinity and a different thermodynamic signature of binding. The ITC data also showed that although the copper ion alone hardly contributes to affinity, substrate binding is enhanced for metal-loaded enzymes that are supplied with cyanide, a mimic of $O_{2}^{−}.$ Studies with CDH and its isolated heme b cytochrome domain unambiguously showed that the cytochrome domain of CDH interacts with the copper site of the LPMO and that substrate binding precludes interaction with CDH. Apart from providing insights into enzyme–substrate interactions in LPMOs, the present observations shed new light on possible mechanisms for electron supply during LPMO action. |
