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Liu Y, Han X, Zhao M, Liu L, Deng Z, Zhao Q, Yu Y. Functional characterization of polyphenol oxidase OfPPO2 supports its involvement in parallel biosynthetic pathways of acteoside. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 119:927-941. [PMID: 38872484 DOI: 10.1111/tpj.16807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 04/17/2024] [Accepted: 04/30/2024] [Indexed: 06/15/2024]
Abstract
Acteoside is a bioactive phenylethanoid glycoside widely distributed throughout the plant kingdom. Because of its two catechol moieties, acteoside displays a variety of beneficial activities. The biosynthetic pathway of acteoside has been largely elucidated, but the assembly logic of two catechol moieties in acteoside remains unclear. Here, we identified a novel polyphenol oxidase OfPPO2 from Osmanthus fragrans, which could hydroxylate various monophenolic substrates, including tyrosine, tyrosol, tyramine, 4-hydroxyphenylacetaldehyde, salidroside, and osmanthuside A, leading to the formation of corresponding catechol-containing intermediates for acteoside biosynthesis. OfPPO2 could also convert osmanthuside B into acteoside, creating catechol moieties directly via post-modification of the acteoside skeleton. The reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis and subcellular localization assay further support the involvement of OfPPO2 in acteoside biosynthesis in planta. These findings suggest that the biosynthesis of acteoside in O. fragrans may follow "parallel routes" rather than the conventionally considered linear route. In support of this hypothesis, the glycosyltransferase OfUGT and the acyltransferase OfAT could direct the flux of diphenolic intermediates generated by OfPPO2 into acteoside. Significantly, OfPPO2 and its orthologs constitute a functionally conserved enzyme family that evolved independently from other known biosynthetic enzymes of acteoside, implying that the substrate promiscuity of this PPO family may offer acteoside-producing plants alternative ways to synthesize acteoside. Overall, this work expands our understanding of parallel pathways plants may employ to efficiently synthesize acteoside, a strategy that may contribute to plants' adaptation to environmental challenges.
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Affiliation(s)
- Yating Liu
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Hubei Clinical Center and Key Laboratory of Intestinal and Colorectal Disease, School of Pharmaceutical Sciences, Wuhan University, 185 East Lake Road, Wuhan, P.R. China
| | - Xiaoyang Han
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Hubei Clinical Center and Key Laboratory of Intestinal and Colorectal Disease, School of Pharmaceutical Sciences, Wuhan University, 185 East Lake Road, Wuhan, P.R. China
| | - Mengya Zhao
- Department of Gynecologic Oncology, Zhongnan Hospital of Wuhan University; Women and Children's Hospital Affiliated to Zhongnan Hospital of Wuhan University, 185 East Lake Road, Wuhan, P.R. China
| | - Lan Liu
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Hubei Clinical Center and Key Laboratory of Intestinal and Colorectal Disease, School of Pharmaceutical Sciences, Wuhan University, 185 East Lake Road, Wuhan, P.R. China
| | - Zixin Deng
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Hubei Clinical Center and Key Laboratory of Intestinal and Colorectal Disease, School of Pharmaceutical Sciences, Wuhan University, 185 East Lake Road, Wuhan, P.R. China
| | - Qiu Zhao
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Hubei Clinical Center and Key Laboratory of Intestinal and Colorectal Disease, School of Pharmaceutical Sciences, Wuhan University, 185 East Lake Road, Wuhan, P.R. China
| | - Yi Yu
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Hubei Clinical Center and Key Laboratory of Intestinal and Colorectal Disease, School of Pharmaceutical Sciences, Wuhan University, 185 East Lake Road, Wuhan, P.R. China
- State Key Laboratory of Non-Food Biomass and Enzyme Technology, Guangxi Academy of Sciences, Nanning, 530007, China
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Mellor SB, Behrendorff JBYH, Ipsen JØ, Crocoll C, Laursen T, Gillam EMJ, Pribil M. Exploiting photosynthesis-driven P450 activity to produce indican in tobacco chloroplasts. FRONTIERS IN PLANT SCIENCE 2023; 13:1049177. [PMID: 36743583 PMCID: PMC9890960 DOI: 10.3389/fpls.2022.1049177] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 12/14/2022] [Indexed: 05/28/2023]
Abstract
Photosynthetic organelles offer attractive features for engineering small molecule bioproduction by their ability to convert solar energy into chemical energy required for metabolism. The possibility to couple biochemical production directly to photosynthetic assimilation as a source of energy and substrates has intrigued metabolic engineers. Specifically, the chemical diversity found in plants often relies on cytochrome P450-mediated hydroxylations that depend on reductant supply for catalysis and which often lead to metabolic bottlenecks for heterologous production of complex molecules. By directing P450 enzymes to plant chloroplasts one can elegantly deal with such redox prerequisites. In this study, we explore the capacity of the plant photosynthetic machinery to drive P450-dependent formation of the indigo precursor indoxyl-β-D-glucoside (indican) by targeting an engineered indican biosynthetic pathway to tobacco (Nicotiana benthamiana) chloroplasts. We show that both native and engineered variants belonging to the human CYP2 family are catalytically active in chloroplasts when driven by photosynthetic reducing power and optimize construct designs to improve productivity. However, while increasing supply of tryptophan leads to an increase in indole accumulation, it does not improve indican productivity, suggesting that P450 activity limits overall productivity. Co-expression of different redox partners also does not improve productivity, indicating that supply of reducing power is not a bottleneck. Finally, in vitro kinetic measurements showed that the different redox partners were efficiently reduced by photosystem I but plant ferredoxin provided the highest light-dependent P450 activity. This study demonstrates the inherent ability of photosynthesis to support P450-dependent metabolic pathways. Plants and photosynthetic microbes are therefore uniquely suited for engineering P450-dependent metabolic pathways regardless of enzyme origin. Our findings have implications for metabolic engineering in photosynthetic hosts for production of high-value chemicals or drug metabolites for pharmacological studies.
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Affiliation(s)
- Silas B. Mellor
- Section for Plant Biochemistry, Department of Plant and Environmental Science, University of Copenhagen, Frederiksberg, Denmark
| | - James B. Y. H. Behrendorff
- School of Biology and Environmental Science, Queensland University of Technology, Brisbane, QLD, Australia
- Australian Research Council (ARC) Centre of Excellence in Synthetic Biology, Queensland University of Technology, Brisbane, QLD, Australia
| | - Johan Ø. Ipsen
- Section for Forest, Nature and Biomass, Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg, Denmark
| | - Christoph Crocoll
- DynaMo Center, Section for Molecular Plant Biology, Department of Plant and Environmental Science, University of Copenhagen, Frederiksberg, Denmark
| | - Tomas Laursen
- Section for Plant Biochemistry, Department of Plant and Environmental Science, University of Copenhagen, Frederiksberg, Denmark
| | - Elizabeth M. J. Gillam
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia
| | - Mathias Pribil
- Section for Molecular Plant Biology, Department of Plant and Environmental Science, University of Copenhagen, Frederiksberg, Denmark
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Linnenbrügger L, Doering L, Lansing H, Fischer K, Eirich J, Finkemeier I, von Schaewen A. Alternative splicing of Arabidopsis G6PD5 recruits NADPH-producing OPPP reactions to the endoplasmic reticulum. FRONTIERS IN PLANT SCIENCE 2022; 13:909624. [PMID: 36119606 PMCID: PMC9478949 DOI: 10.3389/fpls.2022.909624] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 07/20/2022] [Indexed: 06/15/2023]
Abstract
Glucose-6-phosphate dehydrogenase is the rate-limiting enzyme of the oxidative pentose-phosphate pathway (OPPP). The OPPP mainly provides NADPH and sugar-phosphate building blocks for anabolic pathways and is present in all eukaryotes. In plant cells, the irreversible part of the OPPP is found in several compartments. Among the isoforms catalyzing the first OPPP step in Arabidopsis, G6PD1 to G6PD4 target plastids (with G6PD1 being also directed to peroxisomes), whereas G6PD5 and G6PD6 operate in the cytosol. We noticed that alternative splice forms G6PD5.4 and G6PD5.5 encode N-terminally extended proteoforms. Compared to G6PD5.1, RT-PCR signals differed and fluorescent reporter fusions expressed in Arabidopsis protoplasts accumulated in distinct intracellular sites. Co-expression with organelle-specific markers revealed that the G6PD5.4 and G6PD5.5 proteoforms label different subdomains of the endoplasmic reticulum (ER), and analysis of C-terminal roGFP fusions showed that their catalytic domains face the cytosol. In g6pd5-1 g6pd6-2 mutant protoplasts lacking cytosolic G6PDH activity, the ER-bound proteoforms were both active and thus able to form homomers. Among the Arabidopsis 6-phosphogluconolactonases (catalyzing the second OPPP step), we noticed that isoform PGL2 carries a C-terminal CaaX motif that may be prenylated for membrane attachment. Reporter-PGL2 fusions co-localized with G6PD5.4 in ER subdomains, which was abolished by Cys-to-Ser exchange in the 256CSIL motif. Among the Arabidopsis 6-phosphogluconate dehydrogenases (catalyzing the third OPPP step), S-acylated peptides were detected for all three isoforms in a recent palmitoylome, with dual cytosolic/peroxisomal PGD2 displaying three sites. Co-expression of GFP-PGD2 diminished crowding of OFP-G6PD5.4 at the ER, independent of PGL2's presence. Upon pull-down of GFP-G6PD5.4, not only unlabeled PGD2 and PGL2 were enriched, but also enzymes that depend on NADPH provision at the ER, indicative of physical interaction with the OPPP enzymes. When membrane-bound G6PD5.5 and 5.4 variants were co-expressed with KCR1 (ketoacyl-CoA reductase, involved in fatty acid elongation), ATR1 (NADPH:cytochrome-P450 oxidoreductase), or pulled C4H/CYP73A5 (cinnamate 4-hydroxylase) as indirectly (via ATR) NADPH-dependent cytochrome P450 enzyme, co-localization in ER subdomains was observed. Thus, alternative splicing of G6PD5 can direct the NADPH-producing OPPP reactions to the cytosolic face of the ER, where they may operate as membrane-bound metabolon to support several important biosynthetic pathways of plant cells.
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Affiliation(s)
- Loreen Linnenbrügger
- Department of Biology, Molecular Physiology of Plants, Institute of Plant Biology and Biotechnology, University of Münster (WWU Münster), Münster, Germany
| | - Lennart Doering
- Department of Biology, Molecular Physiology of Plants, Institute of Plant Biology and Biotechnology, University of Münster (WWU Münster), Münster, Germany
| | - Hannes Lansing
- Department of Biology, Molecular Physiology of Plants, Institute of Plant Biology and Biotechnology, University of Münster (WWU Münster), Münster, Germany
| | - Kerstin Fischer
- Department of Biology, Molecular Physiology of Plants, Institute of Plant Biology and Biotechnology, University of Münster (WWU Münster), Münster, Germany
| | - Jürgen Eirich
- Department of Biology, Plant Physiology, Institute of Plant Biology and Biotechnology, University of Münster (WWU Münster), Münster, Germany
| | - Iris Finkemeier
- Department of Biology, Plant Physiology, Institute of Plant Biology and Biotechnology, University of Münster (WWU Münster), Münster, Germany
| | - Antje von Schaewen
- Department of Biology, Molecular Physiology of Plants, Institute of Plant Biology and Biotechnology, University of Münster (WWU Münster), Münster, Germany
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Del Giudice R, Putkaradze N, dos Santos BM, Hansen CC, Crocoll C, Motawia MS, Fredslund F, Laursen T, Welner DH. Structure-guided engineering of key amino acids in UGT85B1 controlling substrate and stereo-specificity in aromatic cyanogenic glucoside biosynthesis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 111:1539-1549. [PMID: 35819080 PMCID: PMC9545476 DOI: 10.1111/tpj.15904] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 07/05/2022] [Accepted: 07/07/2022] [Indexed: 06/15/2023]
Abstract
Cyanogenic glucosides are important defense molecules in plants with useful biological activities in animals. Their last biosynthetic step consists of a glycosylation reaction that confers stability and increases structural diversity and is catalyzed by the UDP-dependent glycosyltransferases (UGTs) of glycosyltransferase family 1. These versatile enzymes have large and varied substrate scopes, and the structure-function relationships controlling scope and specificity remain poorly understood. Here, we report substrate-bound crystal structures and rational engineering of substrate and stereo-specificities of UGT85B1 from Sorghum bicolor involved in biosynthesis of the cyanogenic glucoside dhurrin. Substrate specificity was shifted from the natural substrate (S)-p-hydroxymandelonitrile to (S)-mandelonitrile by combining a mutation to abolish hydrogen bonding to the p-hydroxyl group with a mutation to provide steric hindrance at the p-hydroxyl group binding site (V132A/Q225W). Further, stereo-specificity was shifted from (S) to (R) by substituting four rationally chosen residues within 6 Å of the nitrile group (M312T/A313T/H408F/G409A). These activities were compared to two other UGTs involved in the biosynthesis of aromatic cyanogenic glucosides in Prunus dulcis (almond) and Eucalyptus cladocalyx. Together, these studies enabled us to pinpoint factors that drive substrate and stereo-specificities in the cyanogenic glucoside biosynthetic UGTs. The structure-guided engineering of the functional properties of UGT85B1 enhances our understanding of the evolution of UGTs involved in the biosynthesis of cyanogenic glucosides and will enable future engineering efforts towards new biotechnological applications.
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Affiliation(s)
- Rita Del Giudice
- Plant Biochemistry, Department of Plant and Environmental SciencesUniversity of CopenhagenThorvaldsensvej 40DK‐1871CopenhagenDenmark
| | - Natalia Putkaradze
- The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of DenmarkKemitorvet 220DK‐2800Kgs. LyngbyDenmark
| | - Bruna Marques dos Santos
- Plant Biochemistry, Department of Plant and Environmental SciencesUniversity of CopenhagenThorvaldsensvej 40DK‐1871CopenhagenDenmark
| | - Cecilie Cetti Hansen
- Plant Biochemistry, Department of Plant and Environmental SciencesUniversity of CopenhagenThorvaldsensvej 40DK‐1871CopenhagenDenmark
| | - Christoph Crocoll
- DynaMo Center, Molecular Plant Biology, Department of Plant and Environmental SciencesUniversity of CopenhagenThorvaldsensvej 40DK‐1871CopenhagenDenmark
| | - Mohammed Saddik Motawia
- Plant Biochemistry, Department of Plant and Environmental SciencesUniversity of CopenhagenThorvaldsensvej 40DK‐1871CopenhagenDenmark
| | - Folmer Fredslund
- The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of DenmarkKemitorvet 220DK‐2800Kgs. LyngbyDenmark
| | - Tomas Laursen
- Plant Biochemistry, Department of Plant and Environmental SciencesUniversity of CopenhagenThorvaldsensvej 40DK‐1871CopenhagenDenmark
| | - Ditte Hededam Welner
- The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of DenmarkKemitorvet 220DK‐2800Kgs. LyngbyDenmark
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Krishnarjuna B, Im SC, Ravula T, Marte J, Auchus RJ, Ramamoorthy A. Non-Ionic Inulin-Based Polymer Nanodiscs Enable Functional Reconstitution of a Redox Complex Composed of Oppositely Charged CYP450 and CPR in a Lipid Bilayer Membrane. Anal Chem 2022; 94:11908-11915. [PMID: 35977417 PMCID: PMC10851674 DOI: 10.1021/acs.analchem.2c02489] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Although polymer-based lipid nanodiscs are increasingly used in the structural studies of membrane proteins, the charge of the belt-forming polymer is a major limitation for functional reconstitution of membrane proteins possessing an opposite net charge to that of the polymer. This limitation also rules out the reconstitution of a protein-protein complex composed of oppositely charged membrane proteins. In this study, we report the first successful functional reconstitution of a membrane-bound redox complex constituting a cationic cytochrome P450 (CYP450) and an anionic cytochrome P450 reductase (CPR) in non-ionic inulin-based lipid nanodiscs. The gel-to-liquid-crystalline phase-transition temperature (Tm) of DMPC:DMPG (7:3 w/w) lipids in polymer nanodiscs was determined by differential scanning calorimetry (DSC) and 31P NMR experiments. The CYP450-CPR redox complex reconstitution in polymer nanodiscs was characterized by size-exclusion chromatography (SEC), and the electron transfer kinetics was carried out using the stopped-flow technique under anaerobic conditions. The Tm of DMPC:DMPG (7:3 w/w) in polymer nanodiscs measured from 31P NMR agrees with that obtained from DSC and was found to be higher than that for liposomes due to the decreased cooperativity of lipids present in the nanodiscs. The stopped-flow measurements revealed the CYP450-CPR redox complex reconstituted in nanodiscs to be functional, and the electron transfer kinetics was found to be temperature-dependent. Based on the successful demonstration of the use of non-ionic inulin-based polymer nanodiscs reported in this study, we expect them to be useful in studying the function and structures of a variety of membrane proteins/complexes irrespective of the charge of the molecular components. Since the polymer nanodiscs were shown to align in an externally applied magnetic field, they can also be used to measure residual dipolar couplings (RDCs) and residual quadrupolar couplings (RQCs) for various molecules ranging from small molecules to soluble proteins and nucleic acids.
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Affiliation(s)
- Bankala Krishnarjuna
- Biophysics Program, Department of Chemistry, Macromolecular Science and Engineering, Biomedical Engineering, Michigan Neuroscience Institute, The University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Sang-Choul Im
- Department of Pharmacology and Internal Medicine, Division of Metabolism, Endocrinology, & Diabetes, University of Michigan, Ann Arbor, MI 48109
| | - Thirupathi Ravula
- Biophysics Program, Department of Chemistry, Macromolecular Science and Engineering, Biomedical Engineering, Michigan Neuroscience Institute, The University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Joseph Marte
- Biophysics Program, Department of Chemistry, Macromolecular Science and Engineering, Biomedical Engineering, Michigan Neuroscience Institute, The University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Richard J. Auchus
- Department of Pharmacology and Internal Medicine, Division of Metabolism, Endocrinology, & Diabetes, University of Michigan, Ann Arbor, MI 48109
| | - Ayyalusamy Ramamoorthy
- Biophysics Program, Department of Chemistry, Macromolecular Science and Engineering, Biomedical Engineering, Michigan Neuroscience Institute, The University of Michigan, Ann Arbor, MI 48109-1055, USA
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