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Brunecky R, Knott BC, Subramanian V, Linger JG, Beckham GT, Amore A, Taylor LE, Vander Wall TA, Lunin VV, Zheng F, Garrido M, Schuster L, Fulk EM, Farmer S, Himmel ME, Decker SR. Engineering of glycoside hydrolase family 7 cellobiohydrolases directed by natural diversity screening. J Biol Chem 2024; 300:105749. [PMID: 38354778 PMCID: PMC10943489 DOI: 10.1016/j.jbc.2024.105749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 02/05/2024] [Accepted: 02/07/2024] [Indexed: 02/16/2024] Open
Abstract
Protein engineering and screening of processive fungal cellobiohydrolases (CBHs) remain challenging due to limited expression hosts, synergy-dependency, and recalcitrant substrates. In particular, glycoside hydrolase family 7 (GH7) CBHs are critically important for the bioeconomy and typically difficult to engineer. Here, we target the discovery of highly active natural GH7 CBHs and engineering of variants with improved activity. Using experimentally assayed activities of genome mined CBHs, we applied sequence and structural alignments to top performers to identify key point mutations linked to improved activity. From ∼1500 known GH7 sequences, an evolutionarily diverse subset of 57 GH7 CBH genes was expressed in Trichoderma reesei and screened using a multiplexed activity screening assay. Ten catalytically enhanced natural variants were identified, produced, purified, and tested for efficacy using industrially relevant conditions and substrates. Three key amino acids in CBHs with performance comparable or superior to Penicillium funiculosum Cel7A were identified and combinatorially engineered into P. funiculosum cel7a, expressed in T. reesei, and assayed on lignocellulosic biomass. The top performer generated using this combined approach of natural diversity genome mining, experimental assays, and computational modeling produced a 41% increase in conversion extent over native P. funiculosum Cel7A, a 55% increase over the current industrial standard T. reesei Cel7A, and 10% improvement over Aspergillus oryzae Cel7C, the best natural GH7 CBH previously identified in our laboratory.
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Affiliation(s)
- Roman Brunecky
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Brandon C Knott
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Venkataramanan Subramanian
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Jeffrey G Linger
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Gregg T Beckham
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Antonella Amore
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Larry E Taylor
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Todd A Vander Wall
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Vladimir V Lunin
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Fei Zheng
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Mercedes Garrido
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Logan Schuster
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Emily M Fulk
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Samuel Farmer
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Michael E Himmel
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA.
| | - Stephen R Decker
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA.
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