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Chen X, Ye X, Yu X, Zhao J, Song M, Yin D, Yu J. Analysis of the regulatory mechanism of exogenous IAA-mediated tryptophan accumulation and synthesis of endogenous IAA in Chlorococcum humicola. CHEMOSPHERE 2024; 354:141633. [PMID: 38442772 DOI: 10.1016/j.chemosphere.2024.141633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 01/27/2024] [Accepted: 03/01/2024] [Indexed: 03/07/2024]
Abstract
The activated sludge method is widely used for the treatment of phenol-containing wastewater, which gives rise to the problem of toxic residual sludge accumulation. Indole-3-acetic acid (IAA), a typical phytohormone, facilitates the microalgal resistance to toxic inhibition while promoting biomass accumulation. In this study, Chlorococcum humicola (C. humicola) was cultured in toxic sludge extract and different concentrations of IAA were used to regulate its physiological properties and enrichment of high value-added products. Ultimately, proteomics analysis was used to reveal the response mechanism of C. humicola to exogenous IAA. The results showed that the IAA concentration of 5 × 10-6 mol/L (M) was most beneficial for C. humicola to cope with the toxic stress in the sludge extract medium, to promote the activity of rubisco enzyme, to enhance the efficiency of photosynthesis, and, finally, to accumulate protein as a percentage of specific dry weight 1.57 times more than that of the control group. Exogenous IAA altered the relative abundance of various amino acids in C. humicola cells, and proteomic analyses showed that exogenous IAA stimulated the algal cells to produce more indole-3-glycerol phosphate (IGP), indole, and serine by up-regulating the enzymes. These precursors are converted to tryptophan under the regulation of tryptophan synthase (A0A383V983), and tryptophan can be metabolized to endogenous IAA to promote the growth of C. humicola. These findings have important implications for the treatment of toxic residual sludge while enriching for high-value amino acids.
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Affiliation(s)
- Xiurong Chen
- National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China; State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China.
| | - Xiaoyun Ye
- National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China; State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China.
| | - Xiao Yu
- National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China; State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China.
| | - Jiamin Zhao
- National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China; State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China.
| | - Meijing Song
- National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China; State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China.
| | - Danning Yin
- National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China; State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China.
| | - Jiayu Yu
- National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China; State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China.
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2
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Yong CC, Sakurai T, Kaneko H, Horigome A, Mitsuyama E, Nakajima A, Katoh T, Sakanaka M, Abe T, Xiao JZ, Tanaka M, Odamaki T, Katayama T. Human gut-associated Bifidobacterium species salvage exogenous indole, a uremic toxin precursor, to synthesize indole-3-lactic acid via tryptophan. Gut Microbes 2024; 16:2347728. [PMID: 38706226 PMCID: PMC11085991 DOI: 10.1080/19490976.2024.2347728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 04/22/2024] [Indexed: 05/07/2024] Open
Abstract
Indole in the gut is formed from dietary tryptophan by a bacterial tryptophan-indole lyase. Indole not only triggers biofilm formation and antibiotic resistance in gut microbes but also contributes to the progression of kidney dysfunction after absorption by the intestine and sulfation in the liver. As tryptophan is an essential amino acid for humans, these events seem inevitable. Despite this, we show in a proof-of-concept study that exogenous indole can be converted to an immunomodulatory tryptophan metabolite, indole-3-lactic acid (ILA), by a previously unknown microbial metabolic pathway that involves tryptophan synthase β subunit and aromatic lactate dehydrogenase. Selected bifidobacterial strains converted exogenous indole to ILA via tryptophan (Trp), which was demonstrated by incubating the bacterial cells in the presence of (2-13C)-labeled indole and l-serine. Disruption of the responsible genes variedly affected the efficiency of indole bioconversion to Trp and ILA, depending on the strains. Database searches against 11,943 bacterial genomes representing 960 human-associated species revealed that the co-occurrence of tryptophan synthase β subunit and aromatic lactate dehydrogenase is a specific feature of human gut-associated Bifidobacterium species, thus unveiling a new facet of bifidobacteria as probiotics. Indole, which has been assumed to be an end-product of tryptophan metabolism, may thus act as a precursor for the synthesis of a host-interacting metabolite with possible beneficial activities in the complex gut microbial ecosystem.
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Affiliation(s)
- Cheng Chung Yong
- Innovative Research Institute, Morinaga Milk Industry Co Ltd, Zama, Kanagawa, Japan
| | - Takuma Sakurai
- Innovative Research Institute, Morinaga Milk Industry Co Ltd, Zama, Kanagawa, Japan
| | - Hiroki Kaneko
- Innovative Research Institute, Morinaga Milk Industry Co Ltd, Zama, Kanagawa, Japan
| | - Ayako Horigome
- Innovative Research Institute, Morinaga Milk Industry Co Ltd, Zama, Kanagawa, Japan
| | - Eri Mitsuyama
- Innovative Research Institute, Morinaga Milk Industry Co Ltd, Zama, Kanagawa, Japan
| | - Aruto Nakajima
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Toshihiko Katoh
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | | | - Takaaki Abe
- Division of Nephrology, Endocrinology, and Vascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Jin-Zhong Xiao
- Innovative Research Institute, Morinaga Milk Industry Co Ltd, Zama, Kanagawa, Japan
| | - Miyuki Tanaka
- Innovative Research Institute, Morinaga Milk Industry Co Ltd, Zama, Kanagawa, Japan
| | - Toshitaka Odamaki
- Innovative Research Institute, Morinaga Milk Industry Co Ltd, Zama, Kanagawa, Japan
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Takane Katayama
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
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3
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Huang X, Zeng Z, Chen Z, Tong X, Jiang J, He C, Xiang T. Deciphering the potential of a plant growth promoting endophyte Rhizobium sp. WYJ-E13, and functional annotation of the genes involved in the metabolic pathway. Front Microbiol 2022; 13:1035167. [PMID: 36406393 PMCID: PMC9671153 DOI: 10.3389/fmicb.2022.1035167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 10/17/2022] [Indexed: 09/24/2023] Open
Abstract
Plant growth-promoting rhizobacteria (PGPR) are well-acknowledged root endophytic bacteria used for plant growth promotion. However, which metabolites produced by PGPR could promote plant growth remains unclear. Additionally, which genes are responsible for plant growth-promoting traits is also not elucidated. Thus, as comprehensive understanding of the mechanism of endophyte in growth promotion is limited, this study aimed to determine the metabolites and genes involved in plant growth-promotion. We isolated an endophytic Rhizobium sp. WYJ-E13 strain from the roots of Curcuma wenyujin Y.H. Chen et C. Ling, a perennial herb and medicinal plant. The tissue culture experiment showed its plant growth-promoting ability. The bacterium colonization in the root was confirmed by scanning electron microscopy and paraffin sectioning. Furthermore, it was noted that the WYJ-E13 strain produced cytokinin, anthranilic acid, and L-phenylalanine by metabolome analysis. Whole-genome analysis of the strain showed that it consists of a circular chromosome of 4,350,227 bp with an overall GC content of 60.34%, of a 2,149,667 bp plasmid1 with 59.86% GC, and of a 406,180 bp plasmid2 with 58.05% GC. Genome annotation identified 4,349 putative protein-coding genes, 51 tRNAs, and 9 rRNAs. The CDSs number allocated to the Kyoto Encyclopedia of Genes and Genomes, Gene Ontology, and Clusters of Orthologous Genes databases were 2027, 3,175 and 3,849, respectively. Comparative genome analysis displayed that Rhizobium sp. WYJ-E13 possesses the collinear region among three species: Rhizobium acidisoli FH23, Rhizobium gallicum R602 and Rhizobium phaseoli R650. We recognized a total set of genes that are possibly related to plant growth promotion, including genes involved in nitrogen metabolism (nifU, gltA, gltB, gltD, glnA, glnD), hormone production (trp ABCDEFS), sulfur metabolism (cysD, cysE, cysK, cysN), phosphate metabolism (pstA, pstC, phoB, phoH, phoU), and root colonization. Collectively, these findings revealed the roles of WYJ-E13 strain in plant growth-promotion. To the best of our knowledge, this was the first study using whole-genome sequencing for Rhizobium sp. WYJ-E13 associated with C. wenyujin. WYJ-E13 strain has a high potential to be used as Curcuma biofertilizer for sustainable agriculture.
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Affiliation(s)
- Xiaoping Huang
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
- Zhejiang Provincial Key Laboratory for Genetic Improvement and Quality Control of Medicinal Plants, Hangzhou, China
| | - Zhanghui Zeng
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
- Zhejiang Provincial Key Laboratory for Genetic Improvement and Quality Control of Medicinal Plants, Hangzhou, China
| | - Zhehao Chen
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
- Zhejiang Provincial Key Laboratory for Genetic Improvement and Quality Control of Medicinal Plants, Hangzhou, China
| | - Xiaxiu Tong
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Jie Jiang
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Chenjing He
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Taihe Xiang
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
- Zhejiang Provincial Key Laboratory for Genetic Improvement and Quality Control of Medicinal Plants, Hangzhou, China
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4
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Andreani NA, Carraro L, Zhang L, Vos M, Cardazzo B. Transposon mutagenesis in Pseudomonas fluorescens reveals genes involved in blue pigment production and antioxidant protection. Food Microbiol 2019; 82:497-503. [PMID: 31027811 DOI: 10.1016/j.fm.2019.03.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 03/29/2019] [Accepted: 03/30/2019] [Indexed: 12/18/2022]
Abstract
Pseudomonas fluorescens Ps_77 is a blue-pigmenting strain able to cause food product discoloration, causing relevant economic losses especially in the dairy industry. Unlike non-pigmenting P. fluorescens, blue pigmenting strains previously were shown to carry a genomic region that includes homologs of trpABCDF genes, pointing at a possible role of the tryptophan biosynthetic pathway in production of the pigment. Here, we employ random mutagenesis to first identify the genes involved in blue-pigment production in P. fluorescens Ps_77 and second to investigate the biological function of the blue pigment. Genetic analyses based on the mapping of the random insertions allowed the identification of eight genes involved in pigment production, including the second copy of trpB (trpB_1) gene. Phenotypic characterization of Ps_77 white mutants demonstrated that the blue pigment increases oxidative-stress resistance. Indeed, while Ps_77 was growing at a normal rate in presence of 5 mM of H2O2, white mutants were completely inhibited. The antioxidative protection is not available for non-producing bacteria in co-culture with Ps_77.
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Affiliation(s)
- Nadia Andrea Andreani
- Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell'Università, 16, Legnaro, 35020, Padova, Italy; European Centre for Environment and Human Health University of Exeter ESI Building, Penryn Campus, TR109FE, Penryn, UK
| | - Lisa Carraro
- Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell'Università, 16, Legnaro, 35020, Padova, Italy
| | - Lihong Zhang
- European Centre for Environment and Human Health University of Exeter ESI Building, Penryn Campus, TR109FE, Penryn, UK
| | - Michiel Vos
- European Centre for Environment and Human Health University of Exeter ESI Building, Penryn Campus, TR109FE, Penryn, UK
| | - Barbara Cardazzo
- Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell'Università, 16, Legnaro, 35020, Padova, Italy.
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5
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Fleming JR, Schupfner M, Busch F, Baslé A, Ehrmann A, Sterner R, Mayans O. Evolutionary Morphing of Tryptophan Synthase: Functional Mechanisms for the Enzymatic Channeling of Indole. J Mol Biol 2018; 430:5066-5079. [PMID: 30367843 DOI: 10.1016/j.jmb.2018.10.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 08/29/2018] [Accepted: 10/19/2018] [Indexed: 10/28/2022]
Abstract
Tryptophan synthase (TrpS) is a heterotetrameric αββα enzyme that exhibits complex substrate channeling and allosteric mechanisms and is a model system in enzymology. In this work, we characterize proposed early and late evolutionary states of TrpS and show that they have distinct quaternary structures caused by insertions-deletions of sequence segments (indels) in the β-subunit. Remarkably, indole hydrophobic channels that connect α and β active sites have re-emerged in both TrpS types, yet they follow different paths through the β-subunit fold. Also, both TrpS geometries activate the α-subunit through the rearrangement of loops flanking the active site. Our results link evolutionary sequence changes in the enzyme subunits with channeling and allostery in the TrpS enzymes. The findings demonstrate that indels allow protein quaternary architectures to escape "minima" in the evolutionary landscape, thereby overcoming the conservational constraints imposed by existing functional interfaces and being free to morph into new mechanistic enzymes.
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Affiliation(s)
| | - Michael Schupfner
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Florian Busch
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Arnaud Baslé
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK
| | - Alexander Ehrmann
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Reinhard Sterner
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Olga Mayans
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany; Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK.
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6
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Loder AJ, Zeldes BM, Conway JM, Counts JA, Straub CT, Khatibi PA, Lee LL, Vitko NP, Keller MW, Rhaesa AM, Rubinstein GM, Scott IM, Lipscomb GL, Adams MW, Kelly RM. Extreme Thermophiles as Metabolic Engineering Platforms: Strategies and Current Perspective. Ind Biotechnol (New Rochelle N Y) 2016. [DOI: 10.1002/9783527807796.ch14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Andrew J. Loder
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Benjamin M. Zeldes
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Jonathan M. Conway
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - James A. Counts
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Christopher T. Straub
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Piyum A. Khatibi
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Laura L. Lee
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Nicholas P. Vitko
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Matthew W. Keller
- University of Georgia; Department of Biochemistry and Molecular Biology; Life Sciences Bldg., University of Georgia, Athens GA 30602-7229, USA
| | - Amanda M. Rhaesa
- University of Georgia; Department of Biochemistry and Molecular Biology; Life Sciences Bldg., University of Georgia, Athens GA 30602-7229, USA
| | - Gabe M. Rubinstein
- University of Georgia; Department of Biochemistry and Molecular Biology; Life Sciences Bldg., University of Georgia, Athens GA 30602-7229, USA
| | - Israel M. Scott
- University of Georgia; Department of Biochemistry and Molecular Biology; Life Sciences Bldg., University of Georgia, Athens GA 30602-7229, USA
| | - Gina L. Lipscomb
- University of Georgia; Department of Biochemistry and Molecular Biology; Life Sciences Bldg., University of Georgia, Athens GA 30602-7229, USA
| | - Michael W.W. Adams
- University of Georgia; Department of Biochemistry and Molecular Biology; Life Sciences Bldg., University of Georgia, Athens GA 30602-7229, USA
| | - Robert M. Kelly
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
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7
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Jia B, Li Z, Liu J, Sun Y, Jia X, Xuan YH, Zhang J, Jeon CO. A Zinc-Dependent Protease AMZ-tk from a Thermophilic Archaeon is a New Member of the Archaemetzincin Protein Family. Front Microbiol 2015; 6:1380. [PMID: 26733945 PMCID: PMC4681839 DOI: 10.3389/fmicb.2015.01380] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 11/20/2015] [Indexed: 12/23/2022] Open
Abstract
A putative zinc-dependent protease (TK0512) in Thermococcus kodakarensis KOD1 shares a conserved motif with archaemetzincins, which are metalloproteases found in archaea, bacteria, and eukarya. Phylogenetic and sequence analyses showed that TK0512 and its homologues in Thermococcaceae represent new members in the archaemetzincins family, which we named AMZ-tk. We further confirmed its proteolytic activity biochemically by overexpression of the recombinant AMZ-tk in Escherichia coli and characterization of the purified enzyme. In the presence of zinc, the purified enzyme degraded casein, while adding EDTA strongly inhibited the enzyme activity. AMZ-tk also exhibited self-cleavage activity that required Zn2+. These results demonstrated that AMZ-tk is a zinc-dependent protease within the archaemetzincin family. The enzyme displayed activity at alkaline pHs ranging from 7.0 to 10.0, with the optimal pH being 8.0. The optimum temperature for the catalytic activity of AMZ-tk was 55°C. Quantitative reverse transcription-PCR revealed that transcription of AMZ-tk was also up-regulated after exposing the cells to 55 and 65°C. Mutant analysis suggested that Zn2+ binding histidine and catalytic glutamate play key roles in proteolysis. AMZ-tk was thermostable on incubation for 4 h at 70°C in the presence of EDTA. AMZ-tk also retained >50% of its original activity in the presence of both laboratory surfactants and commercial laundry detergents. AMZ-tk further showed antibacterial activity against several bacteria. Therefore, AMZ-tk is of considerable interest for many purposes in view of its activity at alkaline pH, detergents, and thermostability.
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Affiliation(s)
- Baolei Jia
- Department of Life Science, Chung-Ang University Seoul, South Korea
| | - Zhengqun Li
- College of Plant Sciences, Jilin University Changchun, China
| | - Jinliang Liu
- College of Plant Sciences, Jilin University Changchun, China
| | - Ying Sun
- Department of Life Science, Chung-Ang University Seoul, South Korea
| | - Xiaomeng Jia
- Department of Life Science, Chung-Ang University Seoul, South Korea
| | - Yuan Hu Xuan
- College of Plant Protection, Shenyang Agricultural University Shenyang, China
| | - Jiayan Zhang
- College of Plant Sciences, Jilin University Changchun, China
| | - Che Ok Jeon
- Department of Life Science, Chung-Ang University Seoul, South Korea
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8
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Directed evolution of the tryptophan synthase β-subunit for stand-alone function recapitulates allosteric activation. Proc Natl Acad Sci U S A 2015; 112:14599-604. [PMID: 26553994 DOI: 10.1073/pnas.1516401112] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Enzymes in heteromeric, allosterically regulated complexes catalyze a rich array of chemical reactions. Separating the subunits of such complexes, however, often severely attenuates their catalytic activities, because they can no longer be activated by their protein partners. We used directed evolution to explore allosteric regulation as a source of latent catalytic potential using the β-subunit of tryptophan synthase from Pyrococcus furiosus (PfTrpB). As part of its native αββα complex, TrpB efficiently produces tryptophan and tryptophan analogs; activity drops considerably when it is used as a stand-alone catalyst without the α-subunit. Kinetic, spectroscopic, and X-ray crystallographic data show that this lost activity can be recovered by mutations that reproduce the effects of complexation with the α-subunit. The engineered PfTrpB is a powerful platform for production of Trp analogs and for further directed evolution to expand substrate and reaction scope.
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9
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Busch F, Rajendran C, Mayans O, Löffler P, Merkl R, Sterner R. TrpB2 Enzymes are O-Phospho-l-serine Dependent Tryptophan Synthases. Biochemistry 2014; 53:6078-83. [DOI: 10.1021/bi500977y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Florian Busch
- Institute
of Biophysics and Physical Biochemistry, University of Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
| | - Chitra Rajendran
- Institute
of Biophysics and Physical Biochemistry, University of Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
| | - Olga Mayans
- Institute
of Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, United Kingdom
| | - Patrick Löffler
- Institute
of Biophysics and Physical Biochemistry, University of Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
| | - Rainer Merkl
- Institute
of Biophysics and Physical Biochemistry, University of Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
| | - Reinhard Sterner
- Institute
of Biophysics and Physical Biochemistry, University of Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
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