Engineering of Laccase CueO for Improved Electron Transfer in Bioelectrocatalysis by Semi‐Rational Design. Issue 22 (18th March 2020)

• Record Type: Journal Article
• Authors: Zhang, Lingling; Cui, Haiyang; Dhoke, Gaurao V.; Zou, Zhi; Sauer, Daniel F.; Davari, Mehdi D.; Schwaneberg, Ulrich
• Is Part Of: Chemistry. Volume 26:Issue 22(2020)
• Page Start: 4974
• Page End: 4979
• Publication Date: 2020-03-18
• Subjects: bioelectrocatalysis -- copper efflux oxidase -- electron transfer -- oxygen reduction reaction -- site-saturation mutagenesis; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201905598
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Copper efflux oxidase (CueO) from Escherichia coli is a special bacterial laccase due to its fifth copper binding site. Herein, it is discovered that the fifth Cu occupancy plays a crucial and favorable role of electron relay in bioelectrocatalytic oxygen reduction. By substituting the residues at the four coordinated positions of the fifth Cu, 11 beneficial variants are identified with ≥2.5‐fold increased currents at −250 mV (up to 6.13 mA cm −2 ). Detailed electrocatalytic characterization suggests the microenvironment of the fifth Cu binding site governs the electrocatalytic current of CueO. Additionally, further electron transfer analysis assisted by molecular dynamics (MD) simulation demonstrates that an increase in localized structural stability and a decrease of distance between the fifth Cu and the T1 Cu are two main factors contributing to the improved kinetics of CueO variants. It may guide a novel way to tailor laccases and perhaps other oxidoreductases for bioelectrocatalytic applications. Abstract : As a promising cathodic biocatalyst in enzymatic biofuel cells, laccase CueO catalyzes oxygen reduction efficiently thanks to the supplemental Cu binding. Substituting at the four coordinated positions of the fifth Cu binding site was shown to enable the manipulation of electrocatalytic current, which is more remarkable than substitution at the conventional Cu active sites.