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

Alfons K.G. Felice, Christian Schuster, Alan Kadek, Frantisek Filandr, Christophe V.F.P. Laurent, Stefan Scheiblbrandner, Lorenz Schwaiger, Franziska Schachinger, Daniel Kracher, Christoph Sygmund, Petr Man, Petr Halada, Chris Oostenbrink, Roland Ludwig*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish
Pages (from-to)517-532
Number of pages16
JournalACS Catalysis
Issue number2
Publication statusPublished - 15 Jan 2021
Externally publishedYes


  • cellobiose dehydrogenase
  • chimeric enzyme
  • domain swapping
  • electron transfer
  • lytic polysaccharide monooxygenase

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)


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