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KnowVolution of a Fungal Laccase toward Alkaline pH |
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| Authors: | Catalina Novoa Dr Gaurao V Dhoke Dr Diana M Mate Dr Ronny Martínez Dr Thomas Haarmann Martina Schreiter Jasmin Eidner Dr Ruth Schwerdtfeger Dr Patrick Lorenz Mehdi D Davari Dr Felix Jakob Prof?Dr Ulrich Schwaneberg |
| Affiliation: | 1. DWI Leibniz Institute for Interactive Materials, Forckenbeckstrasse 50, 52056 Aachen, Germany;2. Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany;3. DWI Leibniz Institute for Interactive Materials, Forckenbeckstrasse 50, 52056 Aachen, Germany
Present address: Center of Molecular Biology “Severo Ochoa”, Universidad Autónoma de Madrid, Nicolás Cabrera 1, 28049 Madrid, Spain;4. Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany Present address: Departamento de Ingeniería en Alimentos, Instituto de Investigación Multidisciplinario en Ciencia y Tecnología, Universidad de La Serena, Raúl Bitrán 1305, 1720010 La Serena, Chile;5. IAB Enzymes GmbH, Feldbergstrasse 78, 64293 Darmstadt, Germany;6. DWI Leibniz Institute for Interactive Materials, Forckenbeckstrasse 50, 52056 Aachen, Germany Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany |
| Abstract: | To date, commercial laccase preparations are used in the food, textile, and paper and pulp industries (mild pH). Laccases are attractive in the synthesis of dye molecules or oxidative lignin treatment, which take place at high pH (≥8.0). So far, one fungal laccase has been reported to be active at alkaline pH. Herein, engineering of the fungal laccase from Melanocarpus albomyces (MaL) for increased activity toward the substrate 2,6-dimethoxyphenol at pH (≥9.0) is reported. Through a knowledge-gaining directed evolution (KnowVolution) campaign, the key positions Leu365 and Leu513 were identified to increase alkaline tolerance. Both positions are located in close proximity of the T1Cu site. Molecular docking and simulations studies reveal that both substitutions act in a synergic way to stabilize and improve laccase activity at higher pH. Kinetic characterization of the final variant MaL-M1 (L365E/L513M) revealed at pH 9.8 a threefold improved kcat (kcat=(6.0±0.2) s?1) compared with that of wild-type M. albomyces laccase (kcat=(2.11±0.07) s?1). |
| Keywords: | directed evolution laccases molecular dynamics pH protein engineering |