Chimeric Cellobiose Dehydrogenases Reveal the Function of Cytochrome Domain Mobility for the Electron Transfer to Lytic Polysaccharide Monooxygenase

0538043 - MBÚ 2021 RIV US eng J - Journal Article
Felice, A. K.G. - Schuster, C. - Kádek, Alan - Filandr, František - Laurent, C. V.F.P. - Scheiblbrandner, S. - Schwaiger, L. - Schachinger, F. - Kracher, D. - Sygmund, C. - Man, Petr - Halada, Petr - Oostenbrink, C. - Ludwig, R.
Chimeric Cellobiose Dehydrogenases Reveal the Function of Cytochrome Domain Mobility for the Electron Transfer to Lytic Polysaccharide Monooxygenase.
ACS Catalysis. Roč. 11, č. 2 (2021), s. 517-532. ISSN 2155-5435. E-ISSN 2155-5435
R&D Projects: GA ČR(CZ) GF16-34818L; GA MŠMT(CZ) ED1.1.00/02.0109; GA MŠMT(CZ) LQ1604
Research Infrastructure: CIISB - 90043
Institutional support: RVO:61388971
Keywords : cellobiose dehydrogenase * chimeric enzyme * domain swapping * electron transfer * lytic polysaccharide monooxygenase
OECD category: Biochemistry and molecular biology
Impact factor: 13.700, year: 2021
Method of publishing: Open access
https://pubs.acs.org/doi/10.1021/acscatal.0c05294

The natural function of cellobiose dehydrogenase (CDH) to donate electrons from its catalytic flavodehydrogenase (DH) domain via its cytochrome (CYT) domain to lytic polysaccharide monooxygenase (LPMO) is an example of a highly efficient extracellular electron transfer chain. To investigate the function of the CYT domain movement in the two occurring electron transfer steps, two CDHs from the ascomycete Neurospora crassa (NcCDHIIA and NcCDHIIB) and five chimeric CDH enzymes created by domain swapping were studied in combination with the fungus' own LPMOs (NcLPMO9C and NcLPMO9F). Kinetic and electrochemical methods and hydrogen/deuterium exchange mass spectrometry were used to study the domain movement, interaction, and electron transfer kinetics. Molecular docking provided insights into the protein-protein interface, the orientation of domains, and binding energies. We find that the first, interdomain electron transfer step from the catalytic site in the DH domain to the CYT domain depends on steric and electrostatic interface complementarity and the length of the protein linker between both domains but not on the redox potential difference between the FAD and heme b cofactors. After CYT reduction, a conformational change of CDH from its closed state to an open state allows the second, interprotein electron transfer (IPET) step from CYT to LPMO to occur by direct interaction of the b-type heme and the type-2 copper center. Chimeric CDH enzymes favor the open state and achieve higher IPET rates by exposing the heme b cofactor to LPMO. The IPET, which is influenced by interface complementarity and the heme b redox potential, is very efficient with bimolecular rates between 2.9 × 105 and 1.1 × 106 M-1 s-1.
Permanent Link: http://hdl.handle.net/11104/0315871