Interdomain electron transfer in cellobiose dehydrogenase is governed by surface electrostatics
Language English Country Netherlands Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
27851982
DOI
10.1016/j.bbagen.2016.11.016
PII: S0304-4165(16)30424-X
Knihovny.cz E-resources
- Keywords
- Cellobiose dehydrogenase, Direct electron transfer, Electrostatic interaction, Hydrogen/deuterium exchange, Ion mobility, Mass spectrometry,
- MeSH
- Cellobiose metabolism MeSH
- Cytochromes metabolism MeSH
- Deuterium metabolism MeSH
- Electrons MeSH
- Flavins metabolism MeSH
- Fungal Proteins metabolism MeSH
- Glycosylation MeSH
- Fungi metabolism MeSH
- Carbohydrate Dehydrogenases metabolism MeSH
- Hydrogen-Ion Concentration MeSH
- Mixed Function Oxygenases metabolism MeSH
- Polysaccharides metabolism MeSH
- Protein Domains MeSH
- Proteolysis MeSH
- Amino Acid Sequence MeSH
- Static Electricity MeSH
- Electron Transport physiology MeSH
- Hydrogen metabolism MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- cellobiose-quinone oxidoreductase MeSH Browser
- Cellobiose MeSH
- Cytochromes MeSH
- Deuterium MeSH
- Flavins MeSH
- Fungal Proteins MeSH
- Carbohydrate Dehydrogenases MeSH
- Mixed Function Oxygenases MeSH
- Polysaccharides MeSH
- Hydrogen MeSH
BACKGROUND: Cellobiose dehydrogenase (CDH) is a fungal extracellular oxidoreductase which fuels lytic polysaccharide monooxygenase with electrons during cellulose degradation. Interdomain electron transfer between the flavin and cytochrome domain in CDH, preceding the electron flow to lytic polysaccharide monooxygenase, is known to be pH dependent, but the exact mechanism of this regulation has not been experimentally proven so far. METHODS: To investigate the structural aspects underlying the domain interaction in CDH, hydrogen/deuterium exchange (HDX-MS) with improved proteolytic setup (combination of nepenthesin-1 with rhizopuspepsin), native mass spectrometry with ion mobility and electrostatics calculations were used. RESULTS: HDX-MS revealed pH-dependent changes in solvent accessibility and hydrogen bonding at the interdomain interface. Electrostatics calculations identified these differences to result from charge neutralization by protonation and together with ion mobility pointed at higher electrostatic repulsion between CDH domains at neutral pH. In addition, we uncovered extensive O-glycosylation in the linker region and identified the long-unknown exact cleavage point in papain-mediated domain separation. CONCLUSIONS: Transition of CDH between its inactive (open) and interdomain electron transfer-capable (closed) state is shown to be governed by changes in the protein surface electrostatics at the domain interface. Our study confirms that the interdomain electrostatic repulsion is the key factor modulating the functioning of CDH. GENERAL SIGNIFICANCE: The results presented in this paper provide experimental evidence for the role of charge repulsion in the interdomain electron transfer in cellobiose dehydrogenases, which is relevant for exploiting their biotechnological potential in biosensors and biofuel cells.
References provided by Crossref.org
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