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Studying direct electron transfer by site-directed immobilization of cellobiose dehydrogenase

Studying direct electron transfer by site-directed immobilization of cellobiose dehydrogenase
Studying direct electron transfer by site-directed immobilization of cellobiose dehydrogenase
Covalent coupling between a surface exposed cysteine residue and maleimide groups was used to immobilize variants of Myriococcum thermophilum cellobiose dehydrogenase (MtCDH) at multiwall carbon nanotube electrodes. By introducing individual cysteine residues at particular places on the surface of the flavodehydrogenase domain of the flavocytochrome we are able to immobilize the different variants in different orientations. Our results show that direct electron transfer (DET) occurs exclusively through the haem b cofactor and that the redox potential of the haem is unaffected by the orientation of the enzyme. Electron transfer between the haem and the electrode is fast in all cases and at high glucose concentrations the catalytic currents are limited by the rate of inter-domain electron transfer (IET) between the FAD and the haem. Using ferrocene carboxylic acid as a mediator we find that the total amount of immobilized enzyme is 4 to 5 times greater than the amount of enzyme that participates in DET. The role of IET in the overall DET catalysed oxidation was also demonstrated by the effects of changing Ca2+ concentration and by proteolytic cleavage of the cytochrome domain on the DET and MET currents.
cellobiose dehydrogenase •enzyme immobilization • maleimide • direct electron transfer • inter-domain electron transfer
700-713
Meneghello, Marta
0978ae7b-821d-49d9-9dac-a2a8e2306d5b
Al-Lolage, Firas
83184275-ce0e-4887-aee4-4b4c81bf7c06
Ma, Su
768041f5-4f85-4708-8604-698a5bd8430d
Ludwig, Roland
da4bac84-8cce-49c1-b091-d44959b6c245
Bartlett, Philip N.
d99446db-a59d-4f89-96eb-f64b5d8bb075
Meneghello, Marta
0978ae7b-821d-49d9-9dac-a2a8e2306d5b
Al-Lolage, Firas
83184275-ce0e-4887-aee4-4b4c81bf7c06
Ma, Su
768041f5-4f85-4708-8604-698a5bd8430d
Ludwig, Roland
da4bac84-8cce-49c1-b091-d44959b6c245
Bartlett, Philip N.
d99446db-a59d-4f89-96eb-f64b5d8bb075

Meneghello, Marta, Al-Lolage, Firas, Ma, Su, Ludwig, Roland and Bartlett, Philip N. (2019) Studying direct electron transfer by site-directed immobilization of cellobiose dehydrogenase. ChemElectroChem, 6 (3), 700-713. (doi:10.1002/celc.201801503).

Record type: Article

Abstract

Covalent coupling between a surface exposed cysteine residue and maleimide groups was used to immobilize variants of Myriococcum thermophilum cellobiose dehydrogenase (MtCDH) at multiwall carbon nanotube electrodes. By introducing individual cysteine residues at particular places on the surface of the flavodehydrogenase domain of the flavocytochrome we are able to immobilize the different variants in different orientations. Our results show that direct electron transfer (DET) occurs exclusively through the haem b cofactor and that the redox potential of the haem is unaffected by the orientation of the enzyme. Electron transfer between the haem and the electrode is fast in all cases and at high glucose concentrations the catalytic currents are limited by the rate of inter-domain electron transfer (IET) between the FAD and the haem. Using ferrocene carboxylic acid as a mediator we find that the total amount of immobilized enzyme is 4 to 5 times greater than the amount of enzyme that participates in DET. The role of IET in the overall DET catalysed oxidation was also demonstrated by the effects of changing Ca2+ concentration and by proteolytic cleavage of the cytochrome domain on the DET and MET currents.

Text
Revised manuscript celc201801841e_Print - Accepted Manuscript
Restricted to Repository staff only until 30 January 2020.
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More information

Accepted/In Press date: 27 December 2018
e-pub ahead of print date: 30 January 2019
Published date: February 2019
Keywords: cellobiose dehydrogenase •enzyme immobilization • maleimide • direct electron transfer • inter-domain electron transfer

Identifiers

Local EPrints ID: 428245
URI: https://eprints.soton.ac.uk/id/eprint/428245
PURE UUID: a8a24628-d861-4d27-88b0-845ee78e2ddb
ORCID for Marta Meneghello: ORCID iD orcid.org/0000-0003-0099-1783
ORCID for Philip N. Bartlett: ORCID iD orcid.org/0000-0002-7300-6900

Catalogue record

Date deposited: 18 Feb 2019 17:30
Last modified: 08 May 2019 00:36

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