C -type cytochrome-initiated reduction of bacterial lytic polysaccharide monooxygenases - Archive ouverte HAL Access content directly
Journal Articles Biochemical Journal Year : 2021

C -type cytochrome-initiated reduction of bacterial lytic polysaccharide monooxygenases

Jessie Branch
  • Function : Author
Badri Rajagopal
  • Function : Author
Alessandro Paradisi
  • Function : Author
Nick Yates
  • Function : Author
Peter Lindley
  • Function : Author
Jake Smith
  • Function : Author
Kristian Hollingsworth
  • Function : Author
W Bruce Turnbull
  • Function : Author
Alison Parkin
  • Function : Author
Alan Berry
  • Function : Author
Glyn Hemsworth
  • Function : Author
W. Bruce Turnbull
  • Function : Author

Abstract

The release of glucose from lignocellulosic waste for subsequent fermentation into biofuels holds promise for securing humankind's future energy needs. The discovery of a set of copper-dependent enzymes known as lytic polysaccharide monooxygenases (LPMOs) has galvanised new research in this area. LPMOs act by oxidatively introducing chain breaks into cellulose and other polysaccharides, boosting the ability of cellulases to act on the substrate. Although several proteins have been implicated as electron sources in fungal LPMO biochemistry, no equivalent bacterial LPMO electron donors have been previously identified, although the proteins Cbp2D and E from Cellvibrio japonicus have been implicated as potential candidates. Here we analyse a small c-type cytochrome (CjX183) present in Cellvibrio japonicus Cbp2D, and show that it can initiate bacterial CuII/I LPMO reduction and also activate LPMO-catalyzed cellulose-degradation. In the absence of cellulose, CjX183-driven reduction of the LPMO results in less H2O2 production from O2, and correspondingly less oxidative damage to the enzyme than when ascorbate is used as the reducing agent. Significantly, using CjX183 as the activator maintained similar cellulase boosting levels relative to the use of an equivalent amount of ascorbate. Our results therefore add further evidence to the impact that the choice of electron source can have on LPMO action. Furthermore, the study of Cbp2D and other similar proteins may yet reveal new insight into the redox processes governing polysaccharide degradation in bacteria.

Dates and versions

hal-03353934 , version 1 (24-09-2021)

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Jessie Branch, Badri Rajagopal, Alessandro Paradisi, Nick Yates, Peter Lindley, et al.. C -type cytochrome-initiated reduction of bacterial lytic polysaccharide monooxygenases. Biochemical Journal, 2021, 478 (14), pp.2927-2944. ⟨10.1042/BCJ20210376⟩. ⟨hal-03353934⟩
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