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Zhang L, King E, Black WB, Heckmann CM, Wolder A, Cui Y, Nicklen F, Siegel JB, Luo R, Paul CE, Li H. Directed evolution of phosphite dehydrogenase to cycle noncanonical redox cofactors via universal growth selection platform. Nat Commun 2022; 13:5021. [PMID: 36028482 PMCID: PMC9418148 DOI: 10.1038/s41467-022-32727-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 08/13/2022] [Indexed: 11/09/2022] Open
Abstract
Noncanonical redox cofactors are attractive low-cost alternatives to nicotinamide adenine dinucleotide (phosphate) (NAD(P)+) in biotransformation. However, engineering enzymes to utilize them is challenging. Here, we present a high-throughput directed evolution platform which couples cell growth to the in vivo cycling of a noncanonical cofactor, nicotinamide mononucleotide (NMN+). We achieve this by engineering the life-essential glutathione reductase in Escherichia coli to exclusively rely on the reduced NMN+ (NMNH). Using this system, we develop a phosphite dehydrogenase (PTDH) to cycle NMN+ with ~147-fold improved catalytic efficiency, which translates to an industrially viable total turnover number of ~45,000 in cell-free biotransformation without requiring high cofactor concentrations. Moreover, the PTDH variants also exhibit improved activity with another structurally deviant noncanonical cofactor, 1-benzylnicotinamide (BNA+), showcasing their broad applications. Structural modeling prediction reveals a general design principle where the mutations and the smaller, noncanonical cofactors together mimic the steric interactions of the larger, natural cofactors NAD(P)+.
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Affiliation(s)
- Linyue Zhang
- Department of Chemical and Biomolecular Engineering, University of California Irvine, Irvine, CA, 92697, USA
| | - Edward King
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, CA, 92697, USA
| | - William B Black
- Department of Chemical and Biomolecular Engineering, University of California Irvine, Irvine, CA, 92697, USA
| | - Christian M Heckmann
- Biocatalysis, Department of Biotechnology, Delft University of Technology, 2629 HZ, Delft, Netherlands
| | - Allison Wolder
- Biocatalysis, Department of Biotechnology, Delft University of Technology, 2629 HZ, Delft, Netherlands
| | - Youtian Cui
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA, 95616, USA
| | - Francis Nicklen
- Department of Chemical and Biomolecular Engineering, University of California Irvine, Irvine, CA, 92697, USA
| | - Justin B Siegel
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA, 95616, USA
- Department of Biochemistry and Molecular Medicine, University of California, Davis, 2700 Stockton Boulevard, Suite 2102, Sacramento, CA, 95817, USA
- Genome Center, University of California, Davis, 451 Health Sciences Drive, Davis, CA, 95616, USA
| | - Ray Luo
- Department of Chemical and Biomolecular Engineering, University of California Irvine, Irvine, CA, 92697, USA
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, CA, 92697, USA
- Department of Biomedical Engineering, University of California Irvine, Irvine, CA, 92697, USA
- Department Materials Science and Engineering, University of California Irvine, Irvine, CA, 92697, USA
| | - Caroline E Paul
- Biocatalysis, Department of Biotechnology, Delft University of Technology, 2629 HZ, Delft, Netherlands
| | - Han Li
- Department of Chemical and Biomolecular Engineering, University of California Irvine, Irvine, CA, 92697, USA.
- Department of Biomedical Engineering, University of California Irvine, Irvine, CA, 92697, USA.
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2
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Cho HY, Nam MS, Hong HJ, Song WS, Yoon SI. Structural and Biochemical Analysis of the Furan Aldehyde Reductase YugJ from Bacillus subtilis. Int J Mol Sci 2022; 23:ijms23031882. [PMID: 35163804 PMCID: PMC8836905 DOI: 10.3390/ijms23031882] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/29/2022] [Accepted: 02/04/2022] [Indexed: 02/05/2023] Open
Abstract
NAD(H)/NADP(H)-dependent aldehyde/alcohol oxidoreductase (AAOR) participates in a wide range of physiologically important cellular processes by reducing aldehydes or oxidizing alcohols. Among AAOR substrates, furan aldehyde is highly toxic to microorganisms. To counteract the toxic effect of furan aldehyde, some bacteria have evolved AAOR that converts furan aldehyde into a less toxic alcohol. Based on biochemical and structural analyses, we identified Bacillus subtilis YugJ as an atypical AAOR that reduces furan aldehyde. YugJ displayed high substrate specificity toward 5-hydroxymethylfurfural (HMF), a furan aldehyde, in an NADPH- and Ni2+-dependent manner. YugJ folds into a two-domain structure consisting of a Rossmann-like domain and an α-helical domain. YugJ interacts with NADP and Ni2+ using the interdomain cleft of YugJ. A comparative analysis of three YugJ structures indicated that NADP(H) binding plays a key role in modulating the interdomain dynamics of YugJ. Noticeably, a nitrate ion was found in proximity to the nicotinamide ring of NADP in the YugJ structure, and the HMF-reducing activity of YugJ was inhibited by nitrate, providing insights into the substrate-binding mode of YugJ. These findings contribute to the characterization of the YugJ-mediated furan aldehyde reduction mechanism and to the rational design of improved furan aldehyde reductases for the biofuel industry.
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Affiliation(s)
- Hye Yeon Cho
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon 24341, Korea; (H.Y.C.); (M.S.N.); (H.J.H.)
| | - Mi Sun Nam
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon 24341, Korea; (H.Y.C.); (M.S.N.); (H.J.H.)
| | - Ho Jeong Hong
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon 24341, Korea; (H.Y.C.); (M.S.N.); (H.J.H.)
| | - Wan Seok Song
- Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon 24341, Korea
- Correspondence: (W.S.S.); (S.-i.Y.)
| | - Sung-il Yoon
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon 24341, Korea; (H.Y.C.); (M.S.N.); (H.J.H.)
- Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon 24341, Korea
- Correspondence: (W.S.S.); (S.-i.Y.)
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3
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Structural Rearrangements of a Dodecameric Ketol-Acid Reductoisomerase Isolated from a Marine Thermophilic Methanogen. Biomolecules 2021; 11:biom11111679. [PMID: 34827677 PMCID: PMC8615647 DOI: 10.3390/biom11111679] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/05/2021] [Accepted: 11/08/2021] [Indexed: 11/30/2022] Open
Abstract
Ketol-acid reductoisomerase (KARI) orchestrates the biosynthesis of branched-chain amino acids, an elementary reaction in prototrophic organisms as well as a valuable process in biotechnology. Bacterial KARIs belonging to class I organise as dimers or dodecamers and were intensively studied to understand their remarkable specificity towards NADH or NADPH, but also to develop antibiotics. Here, we present the first structural study on a KARI natively isolated from a methanogenic archaea. The dodecameric structure of 0.44-MDa was obtained in two different conformations, an open and close state refined to a resolution of 2.2-Å and 2.1-Å, respectively. These structures illustrate the conformational movement required for substrate and coenzyme binding. While the close state presents the complete NADP bound in front of a partially occupied Mg2+-site, the Mg2+-free open state contains a tartrate at the nicotinamide location and a bound NADP with the adenine-nicotinamide protruding out of the active site. Structural comparisons show a very high conservation of the active site environment and detailed analyses point towards few specific residues required for the dodecamerisation. These residues are not conserved in other dodecameric KARIs that stabilise their trimeric interface differently, suggesting that dodecamerisation, the cellular role of which is still unknown, might have occurred several times in the evolution of KARIs.
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Lindenburg L, Hollfelder F. "NAD-display": Ultrahigh-Throughput in Vitro Screening of NAD(H) Dehydrogenases Using Bead Display and Flow Cytometry. Angew Chem Int Ed Engl 2021; 60:9015-9021. [PMID: 33470025 PMCID: PMC8048591 DOI: 10.1002/anie.202013486] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 12/21/2020] [Indexed: 12/25/2022]
Abstract
NAD(H)‐utiliing enzymes have been the subject of directed evolution campaigns to improve their function. To enable access to a larger swath of sequence space, we demonstrate the utility of a cell‐free, ultrahigh‐throughput directed evolution platform for dehydrogenases. Microbeads (1.5 million per sample) carrying both variant DNA and an immobilised analogue of NAD+ were compartmentalised in water‐in‐oil emulsion droplets, together with cell‐free expression mixture and enzyme substrate, resulting in the recording of the phenotype on each bead. The beads’ phenotype could be read out and sorted for on a flow cytometer by using a highly sensitive fluorescent protein‐based sensor of the NAD+:NADH ratio. Integration of this “NAD‐display” approach with our previously described Split & Mix (SpliMLiB) method for generating large site‐saturation libraries allowed straightforward screening of fully balanced site saturation libraries of formate dehydrogenase, with diversities of 2×104. Based on modular design principles of synthetic biology NAD‐display offers access to sophisticated in vitro selections, avoiding complex technology platforms.
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Affiliation(s)
- Laurens Lindenburg
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, UK.,Current address: Genmab, Uppsalalaan 15, 3584 CT, Utrecht, The Netherlands
| | - Florian Hollfelder
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, UK
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Altered Cofactor Preference of Thermostable StDAPDH by a Single Mutation at K159. Int J Mol Sci 2020; 21:ijms21051788. [PMID: 32150965 PMCID: PMC7084900 DOI: 10.3390/ijms21051788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/02/2020] [Accepted: 03/04/2020] [Indexed: 11/16/2022] Open
Abstract
D-amino acid production from 2-keto acid by reductive amination is an attractive pathway because of its high yield and environmental safety. StDAPDH, a meso-diaminopimelate dehydrogenase (meso-DAPDH) from Symbiobacterium thermophilum, was the first meso-DAPDH to show amination of 2-keto acids. Furthermore, StDAPDH shows excellent thermostability compared to other meso-DAPDHs. However, the cofactor of StDAPDH is NADP(H), which is less common than NAD(H) in industrial applications. Therefore, cofactor engineering for StDAPDH is needed. In this study, the highly conserved cofactor binding sites around the adenosine moiety of NADPH were targeted to determine cofactor specificity. Lysine residues within a loop were found to be critical for the cofactor specificity of StDAPDH. Replacement of lysine with arginine resulted in the activity of pyruvic acid with NADH as the cofactor. The affinity of K159R to pyruvic acid was equal with NADH or NADPH as the cofactor, regardless of the mutation. Molecular dynamics simulations revealed that the large steric hindrance of arginine and the interaction of the salt bridge between NADH and arginine may have restricted the free movement of NADH, which prompted the formation of a stable active conformation of mutant K159R. These results provide further understanding of the catalytic mechanism of StDAPDH and guidance for the cofactor engineering of StDAPDH.
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6
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Abstract
How proteins evolved to recognize and bind their ligands is a key mystery in protein function evolution. To explore this mystery, we study how proteins bind adenine, an ancient fragment. We characterize physicochemical patterns of protein–adenine interactions and link these to proteins’ evolutionary origins. In conflict with previous findings, we see that all of adenine’s hydrogen donors and acceptors have been used to bind proteins, and that adenine binding is likely to have emerged multiple times in evolution. To identify adenine-binding sites of shared origin, we use “themes”: short amino acid segments suggested to constitute evolutionary building blocks. We detect specific themes that are engaged in adenine binding; the detection of these in a protein’s sequence might reveal its function. Proteins’ interactions with ancient ligands may reveal how molecular recognition emerged and evolved. We explore how proteins recognize adenine: a planar rigid fragment found in the most common and ancient ligands. We have developed a computational pipeline that extracts protein–adenine complexes from the Protein Data Bank, structurally superimposes their adenine fragments, and detects the hydrogen bonds mediating the interaction. Our analysis extends the known motifs of protein–adenine interactions in the Watson–Crick edge of adenine and shows that all of adenine’s edges may contribute to molecular recognition. We further show that, on the proteins' side, binding is often mediated by specific amino acid segments (“themes”) that recur across different proteins, such that different proteins use the same themes when binding the same adenine-containing ligands. We identify numerous proteins that feature these themes and are thus likely to bind adenine-containing ligands. Our analysis suggests that adenine binding has emerged multiple times in evolution.
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7
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Lee JY, Park SH, Oh SH, Lee JJ, Kwon KK, Kim SJ, Choi M, Rha E, Lee H, Lee DH, Sung BH, Yeom SJ, Lee SG. Discovery and Biochemical Characterization of a Methanol Dehydrogenase From Lysinibacillus xylanilyticus. Front Bioeng Biotechnol 2020; 8:67. [PMID: 32117944 PMCID: PMC7033420 DOI: 10.3389/fbioe.2020.00067] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 01/27/2020] [Indexed: 11/13/2022] Open
Abstract
Bioconversion of C1 chemicals such as methane and methanol into higher carbon-chain chemicals has been widely studied. Methanol oxidation catalyzed by methanol dehydrogenase (Mdh) is one of the key steps in methanol utilization in bacterial methylotrophy. In bacteria, few NAD+-dependent Mdhs have been reported that convert methanol to formaldehyde. In this study, an uncharacterized Mdh gene from Lysinibacillus xylanilyticus (Lxmdh) was cloned and expressed in Escherichia coli. The maximum alcohol oxidation activity of the recombinant enzyme was observed at pH 9.5 and 55°C in the presence of 10 mM Mg2+. To improve oxidation activity, rational approach-based, site-directed mutagenesis of 16 residues in the putative active site and NAD+-binding region was performed. The mutations S101V, T141S, and A164F improved the enzyme’s specific activity toward methanol compared to that of the wild-type enzyme. These mutants show a slightly higher turnover rate than that of wild-type, although their KM values were increased compared to that of wild-type. Consequently, according the kinetic results, S101, T141, and A164 positions may related to the catalytic activity in the active site for methanol dehydrogenation. It should be further studied other mutant variants with high activity for methanol. In conclusion, we characterized a new Lxmdh and its variants that may be potentially useful for the development of synthetic methylotrophy in the future.
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Affiliation(s)
- Jin-Young Lee
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Sung-Hyun Park
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.,Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology, Daejeon, South Korea
| | - So-Hyung Oh
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.,Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology, Daejeon, South Korea
| | - Jin-Ju Lee
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.,Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology, Daejeon, South Korea
| | - Kil Koang Kwon
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Su-Jin Kim
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Minjeong Choi
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Eugene Rha
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Hyewon Lee
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Dae-Hee Lee
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.,Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology, Daejeon, South Korea
| | - Bong Hyun Sung
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.,Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology, Daejeon, South Korea
| | - Soo-Jin Yeom
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.,School of Biological Sciences and Technology, Chonnam National University, Gwangju, South Korea
| | - Seung-Goo Lee
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.,Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology, Daejeon, South Korea
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8
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Liu Y, Feng Y, Wang L, Guo X, Liu W, Li Q, Wang X, Xue S, Zhao ZK. Structural Insights into Phosphite Dehydrogenase Variants Favoring a Non-natural Redox Cofactor. ACS Catal 2019. [DOI: 10.1021/acscatal.8b04822] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Yuxue Liu
- Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yanbin Feng
- Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Lei Wang
- Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Xiaojia Guo
- Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wujun Liu
- Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Qing Li
- Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xueying Wang
- Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Song Xue
- Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Zongbao Kent Zhao
- Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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9
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Westphal AH, Tischler D, Heinke F, Hofmann S, Gröning JAD, Labudde D, van Berkel WJH. Pyridine Nucleotide Coenzyme Specificity of p-Hydroxybenzoate Hydroxylase and Related Flavoprotein Monooxygenases. Front Microbiol 2018; 9:3050. [PMID: 30631308 PMCID: PMC6315137 DOI: 10.3389/fmicb.2018.03050] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 11/27/2018] [Indexed: 12/03/2022] Open
Abstract
p-Hydroxybenzoate hydroxylase (PHBH; EC 1.14.13.2) is a microbial group A flavoprotein monooxygenase that catalyzes the ortho-hydroxylation of 4-hydroxybenzoate to 3,4-dihydroxybenzoate with the stoichiometric consumption of NAD(P)H and oxygen. PHBH and related enzymes lack a canonical NAD(P)H-binding domain and the way they interact with the pyridine nucleotide coenzyme has remained a conundrum. Previously, we identified a surface exposed protein segment of PHBH from Pseudomonas fluorescens involved in NADPH binding. Here, we report the first amino acid sequences of NADH-preferring PHBHs and a phylogenetic analysis of putative PHBHs identified in currently available bacterial genomes. It was found that PHBHs group into three clades consisting of NADPH-specific, NAD(P)H-dependent and NADH-preferring enzymes. The latter proteins frequently occur in Actinobacteria. To validate the results, we produced several putative PHBHs in Escherichia coli and confirmed their predicted coenzyme preferences. Based on phylogeny, protein energy profiling and lifestyle of PHBH harboring bacteria we propose that the pyridine nucleotide coenzyme specificity of PHBH emerged through adaptive evolution and that the NADH-preferring enzymes are the older versions of PHBH. Structural comparison and distance tree analysis of group A flavoprotein monooxygenases indicated that a similar protein segment as being responsible for the pyridine nucleotide coenzyme specificity of PHBH is involved in determining the pyridine nucleotide coenzyme specificity of the other group A members.
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Affiliation(s)
- Adrie H Westphal
- Laboratory of Biochemistry, Wageningen University and Research, Wageningen, Netherlands
| | - Dirk Tischler
- Interdisziplinäres Ökologisches Zentrum, Technische Universität Bergakademie Freiberg, Freiberg, Germany
| | - Florian Heinke
- Bioinformatics Group Mittweida, University of Applied Sciences Mittweida, Mittweida, Germany
| | - Sarah Hofmann
- Interdisziplinäres Ökologisches Zentrum, Technische Universität Bergakademie Freiberg, Freiberg, Germany
| | - Janosch A D Gröning
- Interdisziplinäres Ökologisches Zentrum, Technische Universität Bergakademie Freiberg, Freiberg, Germany
| | - Dirk Labudde
- Bioinformatics Group Mittweida, University of Applied Sciences Mittweida, Mittweida, Germany
| | - Willem J H van Berkel
- Laboratory of Biochemistry, Wageningen University and Research, Wageningen, Netherlands
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10
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Abstract
Photorespiration limits plant carbon fixation by releasing CO2 and using cellular resources to recycle the product of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) oxygenation, 2-phosphoglycolate. We systematically designed synthetic photorespiration bypasses that combine existing and new-to-nature enzymatic activities and that do not release CO2. Our computational model shows that these bypasses could enhance carbon fixation rate under a range of physiological conditions. To realize the designed bypasses, a glycolate reduction module, which does not exist in nature, is needed to be engineered. By reshaping the substrate and cofactor specificity of two natural enzymes, we established glycolate reduction to glycolaldehyde. With the addition of three natural enzymes, we observed recycling of glycolate to the key Calvin Cycle intermediate ribulose 1,5-bisphosphate with no carbon loss. Photorespiration recycles ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) oxygenation product, 2-phosphoglycolate, back into the Calvin Cycle. Natural photorespiration, however, limits agricultural productivity by dissipating energy and releasing CO2. Several photorespiration bypasses have been previously suggested but were limited to existing enzymes and pathways that release CO2. Here, we harness the power of enzyme and metabolic engineering to establish synthetic routes that bypass photorespiration without CO2 release. By defining specific reaction rules, we systematically identified promising routes that assimilate 2-phosphoglycolate into the Calvin Cycle without carbon loss. We further developed a kinetic–stoichiometric model that indicates that the identified synthetic shunts could potentially enhance carbon fixation rate across the physiological range of irradiation and CO2, even if most of their enzymes operate at a tenth of Rubisco’s maximal carboxylation activity. Glycolate reduction to glycolaldehyde is essential for several of the synthetic shunts but is not known to occur naturally. We, therefore, used computational design and directed evolution to establish this activity in two sequential reactions. An acetyl-CoA synthetase was engineered for higher stability and glycolyl-CoA synthesis. A propionyl-CoA reductase was engineered for higher selectivity for glycolyl-CoA and for use of NADPH over NAD+, thereby favoring reduction over oxidation. The engineered glycolate reduction module was then combined with downstream condensation and assimilation of glycolaldehyde to ribulose 1,5-bisphosphate, thus providing proof of principle for a carbon-conserving photorespiration pathway.
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11
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Abstract
The standard genetic code is robust to mutations during transcription and translation. Point mutations are likely to be synonymous or to preserve the chemical properties of the original amino acid. Saturation mutagenesis experiments suggest that in some cases the best-performing mutant requires replacement of more than a single nucleotide within a codon. These replacements are essentially inaccessible to common error-based laboratory engineering techniques that alter a single nucleotide per mutation event, due to the extreme rarity of adjacent mutations. In this theoretical study, we suggest a radical reordering of the genetic code that maximizes the mutagenic potential of single nucleotide replacements. We explore several possible genetic codes that allow a greater degree of accessibility to the mutational landscape and may result in a hyperevolvable organism that could serve as an ideal platform for directed evolution experiments. We then conclude by evaluating the challenges of constructing such recoded organisms and their potential applications within the field of synthetic biology. The conservative nature of the genetic code prevents bioengineers from efficiently accessing the full mutational landscape of a gene via common error-prone methods. Here, we present two computational approaches to generate alternative genetic codes with increased accessibility. These new codes allow mutational transitions to a larger pool of amino acids and with a greater extent of chemical differences, based on a single nucleotide replacement within the codon, thus increasing evolvability both at the single-gene and at the genome levels. Given the widespread use of these techniques for strain and protein improvement, along with more fundamental evolutionary biology questions, the use of recoded organisms that maximize evolvability should significantly improve the efficiency of directed evolution, library generation, and fitness maximization.
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12
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Belsare KD, Andorfer MC, Cardenas FS, Chael JR, Park HJ, Lewis JC. A Simple Combinatorial Codon Mutagenesis Method for Targeted Protein Engineering. ACS Synth Biol 2017; 6:416-420. [PMID: 28033708 DOI: 10.1021/acssynbio.6b00297] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Directed evolution is a powerful tool for optimizing enzymes, and mutagenesis methods that improve enzyme library quality can significantly expedite the evolution process. Here, we report a simple method for targeted combinatorial codon mutagenesis (CCM). To demonstrate the utility of this method for protein engineering, CCM libraries were constructed for cytochrome P450BM3, pfu prolyl oligopeptidase, and the flavin-dependent halogenase RebH; 10-26 sites were targeted for codon mutagenesis in each of these enzymes, and libraries with a tunable average of 1-7 codon mutations per gene were generated. Each of these libraries provided improved enzymes for their respective transformations, which highlights the generality, simplicity, and tunability of CCM for targeted protein engineering.
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Affiliation(s)
- Ketaki D. Belsare
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Mary C. Andorfer
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Frida S. Cardenas
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Julia R. Chael
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Hyun June Park
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Jared C. Lewis
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
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13
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Cahn JKB, Werlang CA, Baumschlager A, Brinkmann-Chen S, Mayo SL, Arnold FH. A General Tool for Engineering the NAD/NADP Cofactor Preference of Oxidoreductases. ACS Synth Biol 2017; 6:326-333. [PMID: 27648601 DOI: 10.1021/acssynbio.6b00188] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The ability to control enzymatic nicotinamide cofactor utilization is critical for engineering efficient metabolic pathways. However, the complex interactions that determine cofactor-binding preference render this engineering particularly challenging. Physics-based models have been insufficiently accurate and blind directed evolution methods too inefficient to be widely adopted. Building on a comprehensive survey of previous studies and our own prior engineering successes, we present a structure-guided, semirational strategy for reversing enzymatic nicotinamide cofactor specificity. This heuristic-based approach leverages the diversity and sensitivity of catalytically productive cofactor binding geometries to limit the problem to an experimentally tractable scale. We demonstrate the efficacy of this strategy by inverting the cofactor specificity of four structurally diverse NADP-dependent enzymes: glyoxylate reductase, cinnamyl alcohol dehydrogenase, xylose reductase, and iron-containing alcohol dehydrogenase. The analytical components of this approach have been fully automated and are available in the form of an easy-to-use web tool: Cofactor Specificity Reversal-Structural Analysis and Library Design (CSR-SALAD).
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Affiliation(s)
- Jackson K. B. Cahn
- Division of Chemistry and Chemical Engineering, and ‡Division of Biology and Biological
Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Caroline A. Werlang
- Division of Chemistry and Chemical Engineering, and ‡Division of Biology and Biological
Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Armin Baumschlager
- Division of Chemistry and Chemical Engineering, and ‡Division of Biology and Biological
Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Sabine Brinkmann-Chen
- Division of Chemistry and Chemical Engineering, and ‡Division of Biology and Biological
Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Stephen L. Mayo
- Division of Chemistry and Chemical Engineering, and ‡Division of Biology and Biological
Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Frances H. Arnold
- Division of Chemistry and Chemical Engineering, and ‡Division of Biology and Biological
Engineering, California Institute of Technology, Pasadena, California 91125, United States
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Tiwari V. In vitro Engineering of Novel Bioactivity in the Natural Enzymes. Front Chem 2016; 4:39. [PMID: 27774447 PMCID: PMC5054688 DOI: 10.3389/fchem.2016.00039] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 09/21/2016] [Indexed: 11/23/2022] Open
Abstract
Enzymes catalyze various biochemical functions with high efficiency and specificity. In vitro design of the enzyme leads to novel bioactivity in this natural biomolecule that give answers of some vital questions like crucial residues in binding with substrate, molecular evolution, cofactor specificity etc. Enzyme engineering technology involves directed evolution, rational designing, semi-rational designing, and structure-based designing using chemical modifications. Similarly, combined computational and in vitro evolution approaches together help in artificial designing of novel bioactivity in the natural enzyme. DNA shuffling, error prone PCR and staggered extension process are used to artificially redesign active site of enzyme, which can alter its efficiency and specificity. Modifications of the enzyme can lead to the discovery of new path of molecular evolution, designing of efficient enzymes, locating active sites and crucial residues, shift in substrate, and cofactor specificity. The methods and thermodynamics of in vitro designing of the enzyme are also discussed. Similarly, engineered thermophilic and psychrophilic enzymes attain substrate specificity and activity of mesophilic enzymes that may also be beneficial for industry and therapeutics.
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Affiliation(s)
- Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan Ajmer, India
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