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Does Tyrosine Protect S. coelicolor Laccase from Oxidative Degradation or Act as an Extended Catalytic Site?

Kielb, Patrycja J. and Teutloff, Christian and Bittl, Robert and Gray, Harry B. and Winkler, Jay R. (2022) Does Tyrosine Protect S. coelicolor Laccase from Oxidative Degradation or Act as an Extended Catalytic Site? Journal of Physical Chemistry B, 126 (40). pp. 7943-7949. ISSN 1520-6106. doi:10.1021/acs.jpcb.2c04835.

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We have investigated the roles of tyrosine (Tyr) and tryptophan (Trp) residues in the four-electron reduction of oxygen catalyzed by Streptomyces coelicolor laccase (SLAC). During normal enzymatic turnover in laccases, reducing equivalents are delivered to a type 1 Cu center (Cu_(T1)) and then are transferred over 13 Å to a trinuclear Cu site (TNC: (Cu_(T3))₂Cu_(T2)) where O₂ reduction occurs. The TNC in SLAC is surrounded by a large cluster of Tyr and Trp residues that can provide reducing equivalents when the normal flow of electrons is disrupted. Prior studies by Canters and co-workers [J.Am.Chem.Soc.2009, 131 (33), 11680-11682] have shown that when O₂ reacts with a reduced SLAC variant lacking the Cu_(T1) center, a Tyr108• radical near the TNC forms rapidly. We have found that the Tyr108• radical is reduced 10 times faster than Cu_(T1)²⁺ by excess ascorbate, possibly because of radical transfer along Tyr/Trp chains.

Item Type:Article
Related URLs:
URLURL TypeDescription
Kielb, Patrycja J.0000-0003-2809-0813
Teutloff, Christian0000-0001-6949-1985
Bittl, Robert0000-0003-4103-3768
Gray, Harry B.0000-0002-7937-7876
Winkler, Jay R.0000-0002-4453-9716
Additional Information:We thank Paul Oyala for assistance with EPR experiments at Caltech, Yuling Sheng for help with protein expression and purification, Prof. Silke Leimkühler for providing access to a biochemistry lab, and Prof. Henrike Müller-Werkmeister for serving as host for P.K. during her stay at the University of Potsdam, Germany. Research was supported by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health under Award Number R01DK019038. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Additional support was provided by the Excellence Cluster “Unifying Systems in Catalysis” financed by Deutsche Forschungsgemeinschaft (DFG) and the Arnold and Mabel Beckman Foundation.
Funding AgencyGrant Number
Deutsche Forschungsgemeinschaft (DFG)UNSPECIFIED
Arnold and Mabel Beckman FoundationUNSPECIFIED
Issue or Number:40
Record Number:CaltechAUTHORS:20221027-402241500.8
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ID Code:117635
Deposited By: Research Services Depository
Deposited On:08 Nov 2022 19:28
Last Modified:08 Nov 2022 19:28

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