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Engineering of Laccase CueO for Improved Electron Transfer in Bioelectrocatalysis by Semi‐Rational Design
Author(s) -
Zhang Lingling,
Cui Haiyang,
Dhoke Gaurao V.,
Zou Zhi,
Sauer Daniel F.,
Davari Mehdi D.,
Schwaneberg Ulrich
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201905598
Subject(s) - electron transfer , laccase , chemistry , copper , multicopper oxidase , kinetics , electron transport chain , metalloprotein , rational design , combinatorial chemistry , biophysics , nanotechnology , materials science , photochemistry , enzyme , biochemistry , biology , organic chemistry , physics , quantum mechanics
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.