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Lou D, Cao Y, Duan H, Tan J, Li B, Zhou Y, Wang D. Characterization of a Novel Thermostable 7α-Hydroxysteroid Dehydrogenase. Protein Pept Lett 2024; 31:153-160. [PMID: 38288819 DOI: 10.2174/0109298665279004231229100320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 12/21/2023] [Accepted: 12/23/2023] [Indexed: 05/30/2024]
Abstract
BACKGROUND 7α-Hydroxysteroid dehydrogenase (7α-HSDH) plays a pivotal role in vivo in the biotransformation of secondary bile acids and has great potential in industrial biosynthesis due to its broad substrate specificity. In this study, we expressed and characterized a novel thermostable 7α-HSDH (named Sa 7α-HSDH). METHODS The DNA sequence was derived from the black bear gut microbiome metagenomic sequencing data, and the coding sequence of Sa 7α-HSDH was chemically synthesized. The heterologous expression of the enzyme was carried out using the pGEX-6p-1 vector. Subsequently, the activity of the purified enzyme was studied by measuring the absorbance change at 340 nm. Finally, the three-dimensional structure was predicted with AlphaFold2. RESULTS Coenzyme screening results confirmed it to be NAD(H) dependent. Substrate specificity test revealed that Sa 7α-HSDH could catalyze taurochenodeoxycholic acid (TCDCA) with catalytic efficiency (kcat/Km) 3.81 S-1 mM-1. The optimum temperature of Sa 7α-HSDH was measured to be 75°C, confirming that it belongs to thermophilic enzymes. Additionally, its thermostability was assessed using an accelerated stability test over 32 hours. The catalytic activity of Sa 7α-HSDH remained largely unchanged for the first 24 hours and retained over 90% of its functionality after 32 hours at 50°C. Sa 7α-HSDH exhibited maximal activity at pH 10. The effect of metal ions-K+, Na+, Mg2+ and Cu2+-on the enzymatic activity of Sa 7α-HSDH was investigated. Only Mg2+ was observed to enhance the enzyme's activity by 27% at a concentration of 300 mM. Neither K+ nor Na+ had a significant influence on activity. Only Cu2+ was found to reduce enzyme activity. CONCLUSION We characterized the thermostable 7α-HSDH, which provides a promising biocatalyst for bioconversion of steroids at high reaction temperatures.
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Affiliation(s)
- Deshuai Lou
- Chongqing Key Laboratory of Medicinal Resources in the Three Gorges Reservoir Region, School of Biological and Chemical Engineering, Chongqing University of Education, Chongqing, 400067, China
| | - Yangyang Cao
- Chongqing Key Laboratory of Medicinal Resources in the Three Gorges Reservoir Region, School of Biological and Chemical Engineering, Chongqing University of Education, Chongqing, 400067, China
| | - Hongtao Duan
- Chongqing Key Laboratory of Medicinal Resources in the Three Gorges Reservoir Region, School of Biological and Chemical Engineering, Chongqing University of Education, Chongqing, 400067, China
| | - Jun Tan
- Chongqing Key Laboratory of Medicinal Resources in the Three Gorges Reservoir Region, School of Biological and Chemical Engineering, Chongqing University of Education, Chongqing, 400067, China
| | - Binyan Li
- Chongqing Key Laboratory of Medicinal Resources in the Three Gorges Reservoir Region, School of Biological and Chemical Engineering, Chongqing University of Education, Chongqing, 400067, China
| | - Yuanjun Zhou
- Chongqing Key Laboratory of Medicinal Resources in the Three Gorges Reservoir Region, School of Biological and Chemical Engineering, Chongqing University of Education, Chongqing, 400067, China
| | - Dong Wang
- School of Information Science and Engineering, University of Jinan, Jinan, 250022, China
- Shandong Provincial Key Laboratory of Network Based Intelligent Computing, Jinan, 250022, China
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Samarina L, Wang S, Malyukova L, Bobrovskikh A, Doroshkov A, Koninskaya N, Shkhalakhova R, Matskiv A, Fedorina J, Fizikova A, Manakhova K, Loshkaryova S, Tutberidze T, Ryndin A, Khlestkina E. Long-term cold, freezing and drought: overlapping and specific regulatory mechanisms and signal transduction in tea plant ( Camellia sinensis (L.) Kuntze). FRONTIERS IN PLANT SCIENCE 2023; 14:1145793. [PMID: 37235017 PMCID: PMC10206121 DOI: 10.3389/fpls.2023.1145793] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 04/11/2023] [Indexed: 05/28/2023]
Abstract
Introduction Low temperatures and drought are two main environmental constraints reducing the yield and geographical distribution of horticultural crops worldwide. Understanding the genetic crosstalk between stress responses has potential importance for crop improvement. Methods In this study, Illumina RNA-seq and Pac-Bio genome resequencing were used to annotate genes and analyze transcriptome dynamics in tea plants under long-term cold, freezing, and drought. Results The highest number of differentially expressed genes (DEGs) was identified under long-term cold (7,896) and freezing (7,915), with 3,532 and 3,780 upregulated genes, respectively. The lowest number of DEGs was observed under 3-day drought (47) and 9-day drought (220), with five and 112 genes upregulated, respectively. The recovery after the cold had 6.5 times greater DEG numbers as compared to the drought recovery. Only 17.9% of cold-induced genes were upregulated by drought. In total, 1,492 transcription factor genes related to 57 families were identified. However, only 20 transcription factor genes were commonly upregulated by cold, freezing, and drought. Among the 232 common upregulated DEGs, most were related to signal transduction, cell wall remodeling, and lipid metabolism. Co-expression analysis and network reconstruction showed 19 genes with the highest co-expression connectivity: seven genes are related to cell wall remodeling (GATL7, UXS4, PRP-F1, 4CL, UEL-1, UDP-Arap, and TBL32), four genes are related to calcium-signaling (PXL1, Strap, CRT, and CIPK6), three genes are related to photo-perception (GIL1, CHUP1, and DnaJ11), two genes are related to hormone signaling (TTL3 and GID1C-like), two genes are involved in ROS signaling (ERO1 and CXE11), and one gene is related to the phenylpropanoid pathway (GALT6). Discussion Based on our results, several important overlapping mechanisms of long-term stress responses include cell wall remodeling through lignin biosynthesis, o-acetylation of polysaccharides, pectin biosynthesis and branching, and xyloglucan and arabinogalactan biosynthesis. This study provides new insight into long-term stress responses in woody crops, and a set of new target candidate genes were identified for molecular breeding aimed at tolerance to abiotic stresses.
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Affiliation(s)
- Lidiia Samarina
- Federal Research Centre the Subtropical Scientific Centre, Russian Academy of Sciences, Sochi, Russia
- Center of Genetics and Life Sciences, Sirius University of Science and Technology, Sirius, Russia
| | - Songbo Wang
- Federal Research Centre the Subtropical Scientific Centre, Russian Academy of Sciences, Sochi, Russia
| | - Lyudmila Malyukova
- Federal Research Centre the Subtropical Scientific Centre, Russian Academy of Sciences, Sochi, Russia
| | - Alexandr Bobrovskikh
- Institute of Cytology and Genetics Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
| | - Alexey Doroshkov
- Institute of Cytology and Genetics Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
| | - Natalia Koninskaya
- Federal Research Centre the Subtropical Scientific Centre, Russian Academy of Sciences, Sochi, Russia
| | - Ruset Shkhalakhova
- Federal Research Centre the Subtropical Scientific Centre, Russian Academy of Sciences, Sochi, Russia
| | - Alexandra Matskiv
- Federal Research Centre the Subtropical Scientific Centre, Russian Academy of Sciences, Sochi, Russia
| | - Jaroslava Fedorina
- Federal Research Centre the Subtropical Scientific Centre, Russian Academy of Sciences, Sochi, Russia
- Center of Genetics and Life Sciences, Sirius University of Science and Technology, Sirius, Russia
| | - Anastasia Fizikova
- Federal Research Centre the Subtropical Scientific Centre, Russian Academy of Sciences, Sochi, Russia
- Center of Genetics and Life Sciences, Sirius University of Science and Technology, Sirius, Russia
| | - Karina Manakhova
- Federal Research Centre the Subtropical Scientific Centre, Russian Academy of Sciences, Sochi, Russia
- Center of Genetics and Life Sciences, Sirius University of Science and Technology, Sirius, Russia
| | - Svetlana Loshkaryova
- Federal Research Centre the Subtropical Scientific Centre, Russian Academy of Sciences, Sochi, Russia
| | - Tsiala Tutberidze
- Federal Research Centre the Subtropical Scientific Centre, Russian Academy of Sciences, Sochi, Russia
| | - Alexey Ryndin
- Federal Research Centre the Subtropical Scientific Centre, Russian Academy of Sciences, Sochi, Russia
| | - Elena Khlestkina
- Center of Genetics and Life Sciences, Sirius University of Science and Technology, Sirius, Russia
- Federal Research Center, N. I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR), Saint Petersburg, Russia
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Moia IC, Pereira SB, Domizio P, De Philippis R, Adessi A. Phormidium ambiguum and Leptolyngbya ohadii Exopolysaccharides under Low Water Availability. Polymers (Basel) 2023; 15:polym15081889. [PMID: 37112036 PMCID: PMC10142279 DOI: 10.3390/polym15081889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 03/31/2023] [Accepted: 04/12/2023] [Indexed: 04/29/2023] Open
Abstract
Cyanobacteria can cope with various environmental stressors, due to the excretion of exopolysaccharides (EPS). However, little is known about how the composition of these polymers may change according to water availability. This work aimed at characterizing the EPS of Phormidium ambiguum (Oscillatoriales; Oscillatoriaceae) and Leptolyngbya ohadii (Pseudanabaenales; Leptolyngbyaceae), when grown as biocrusts and biofilms, subject to water deprivation. The following EPS fractions were quantified and characterized: soluble (loosely bound, LB) and condensed (tightly bound, TB) for biocrusts, released (RPS), and sheathed in P. ambiguum and glycocalyx (G-EPS) in L. ohadii for biofilms. For both cyanobacteria upon water deprivation, glucose was the main monosaccharide present and the amount of TB-EPS resulted was significantly higher, confirming its importance in these soil-based formations. Different profiles of monosaccharides composing the EPSs were observed, as for example the higher concentration of deoxysugars observed in biocrusts compared to biofilms, demonstrating the plasticity of the cells to modify EPS composition as a response to different stresses. For both cyanobacteria, both in biofilms and biocrusts, water deprivation induced the production of simpler carbohydrates, with an increased dominance index of the composing monosaccharides. The results obtained are useful in understanding how these very relevant cyanobacterial species are sensitively modifying the EPS secreted when subject to water deprivation and could lead to consider them as suitable inoculants in degraded soils.
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Affiliation(s)
- Isabela C Moia
- DAGRI-Department of Agriculture, Food, Environment and Forestry, University of Florence, Via Maragliano 77, 50144 Firenze, Italy
| | - Sara B Pereira
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal
- IBMC-Instituto de Biologia Celular e Molecular, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal
| | - Paola Domizio
- DAGRI-Department of Agriculture, Food, Environment and Forestry, University of Florence, Via Maragliano 77, 50144 Firenze, Italy
| | - Roberto De Philippis
- DAGRI-Department of Agriculture, Food, Environment and Forestry, University of Florence, Via Maragliano 77, 50144 Firenze, Italy
| | - Alessandra Adessi
- DAGRI-Department of Agriculture, Food, Environment and Forestry, University of Florence, Via Maragliano 77, 50144 Firenze, Italy
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Wang Y, Samarina L, Mallano AI, Tong W, Xia E. Recent progress and perspectives on physiological and molecular mechanisms underlying cold tolerance of tea plants. FRONTIERS IN PLANT SCIENCE 2023; 14:1145609. [PMID: 36866358 PMCID: PMC9971632 DOI: 10.3389/fpls.2023.1145609] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 02/02/2023] [Indexed: 06/18/2023]
Abstract
Tea is one of the most consumed and widely planted beverage plant worldwide, which contains many important economic, healthy, and cultural values. Low temperature inflicts serious damage to tea yields and quality. To cope with cold stress, tea plants have evolved a cascade of physiological and molecular mechanisms to rescue the metabolic disorders in plant cells caused by the cold stress; this includes physiological, biochemical changes and molecular regulation of genes and associated pathways. Understanding the physiological and molecular mechanisms underlying how tea plants perceive and respond to cold stress is of great significance to breed new varieties with improved quality and stress resistance. In this review, we summarized the putative cold signal sensors and molecular regulation of the CBF cascade pathway in cold acclimation. We also broadly reviewed the functions and potential regulation networks of 128 cold-responsive gene families of tea plants reported in the literature, including those particularly regulated by light, phytohormone, and glycometabolism. We discussed exogenous treatments, including ABA, MeJA, melatonin, GABA, spermidine and airborne nerolidol that have been reported as effective ways to improve cold resistance in tea plants. We also present perspectives and possible challenges for functional genomic studies on cold tolerance of tea plants in the future.
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Affiliation(s)
- Yanli Wang
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, China
| | - Lidia Samarina
- Federal Research Centre the Subtropical Scientific Centre, The Russian Academy of Sciences, Sochi, Russia
| | - Ali Inayat Mallano
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, China
| | - Wei Tong
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, China
| | - Enhua Xia
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, China
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Borg AJE, Esquivias O, Coines J, Rovira C, Nidetzky B. Enzymatische C4-Epimerisierung von UDP-Glucuronsäure: präzise gesteuerte Rotation eines transienten 4-Ketointermediats für eine invertierende Reaktion ohne Decarboxylierung. ANGEWANDTE CHEMIE (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 135:e202211937. [PMID: 38515538 PMCID: PMC10952283 DOI: 10.1002/ange.202211937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Indexed: 03/23/2024]
Abstract
AbstractUDP‐Glucuronsäure(UDP‐GlcA)‐4‐Epimerase repräsentiert eine wichtige Fragestellung in der Enzymkatalyse: die Balance zwischen konformativer Flexibilität und genauer Positionierung. Das Enzym koordiniert die C4‐Oxidation des Substrats durch NAD+ mit der Rotation eines leicht decarboxylierbaren β‐Ketosäure‐Intermediats im aktiven Zentrum zur Ermöglichung der stereoinvertierenden Reduktion der Ketogruppe durch NADH. Wir zeigen hier die nur schwer erfassbare Rotationskoordinate des 4‐Ketointermediats. Distorsion des Zuckerrings in eine Boot‐Konformation erzeugt torsionale Mobilität in der Bindungstasche des Enzyms. Die Endpunkte der Rotation zeigen den 4‐Ketozucker in einer unverformten 4C1‐Sesselkonformation. Die äquatorial positionierte Carboxylatgruppe ist ungünstig für die 4‐Ketozucker‐Decarboxylierung. Varianten der Epimerase zeigen Decarboxylierung, wenn sie die Bindung mit der Carboxylatgruppe im entgegengesetzten Rotationsisomer des Substrats entfernen. R185A/D‐Substitutionen wandeln die Epimerase in UDP‐Xylose‐Synthasen um, welche UDP‐GlcA in stereospezifischen, konfigurationserhaltenden Reaktionen decarboxylieren.
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Affiliation(s)
- Annika J. E. Borg
- Institut für Biotechnologie und BioprozesstechnikTechnische Universität GrazPetersgasse 12/18010GrazÖsterreich
| | - Oriol Esquivias
- Department of Inorganic and Organic Chemistry (Section of Organic Chemistry)Institute of Computational and Theoretical Chemistry (IQTCUB)Martí i Franquès 108028BarcelonaSpanien
| | - Joan Coines
- Department of Inorganic and Organic Chemistry (Section of Organic Chemistry)Institute of Computational and Theoretical Chemistry (IQTCUB)Martí i Franquès 108028BarcelonaSpanien
- Derzeitige Adresse: Nostrum BiodiscoveryAv. De Josep Tarradellas, 8–1008029BarcelonaSpanien
| | - Carme Rovira
- Department of Inorganic and Organic Chemistry (Section of Organic Chemistry)Institute of Computational and Theoretical Chemistry (IQTCUB)Martí i Franquès 108028BarcelonaSpanien
- Institució Catalana de Recerca i Estudis Avançats (ICREA)Passeig Lluís Companys, 2308010BarcelonaSpanien
| | - Bernd Nidetzky
- Institut für Biotechnologie und BioprozesstechnikTechnische Universität GrazPetersgasse 12/18010GrazÖsterreich
- Austrian Center of Industrial Biotechnology (acib)Krenngasse 378010GrazÖsterreich
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Borg AJE, Esquivias O, Coines J, Rovira C, Nidetzky B. Enzymatic C4-Epimerization of UDP-Glucuronic Acid: Precisely Steered Rotation of a Transient 4-Keto Intermediate for an Inverted Reaction without Decarboxylation. Angew Chem Int Ed Engl 2023; 62:e202211937. [PMID: 36308301 PMCID: PMC10107529 DOI: 10.1002/anie.202211937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 10/03/2022] [Accepted: 10/26/2022] [Indexed: 11/06/2022]
Abstract
UDP-glucuronic acid (UDP-GlcA) 4-epimerase illustrates an important problem regarding enzyme catalysis: balancing conformational flexibility with precise positioning. The enzyme coordinates the C4-oxidation of the substrate by NAD+ and rotation of a decarboxylation-prone β-keto acid intermediate in the active site, enabling stereoinverting reduction of the keto group by NADH. We reveal the elusive rotational landscape of the 4-keto intermediate. Distortion of the sugar ring into boat conformations induces torsional mobility in the enzyme's binding pocket. The rotational endpoints show that the 4-keto sugar has an undistorted 4 C1 chair conformation. The equatorially placed carboxylate group disfavors decarboxylation of the 4-keto sugar. Epimerase variants lead to decarboxylation upon removal of the binding interactions with the carboxylate group in the opposite rotational isomer of the substrate. Substitutions R185A/D convert the epimerase into UDP-xylose synthases that decarboxylate UDP-GlcA in stereospecific, configuration-retaining reactions.
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Affiliation(s)
- Annika J E Borg
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 12/1, 8010, Graz, Austria
| | - Oriol Esquivias
- Department of Inorganic and Organic Chemistry (Section of Organic Chemistry), Institute of Computational and Theoretical Chemistry (IQTCUB), Martí i Franquès 1, 08028, Barcelona, Spain
| | - Joan Coines
- Department of Inorganic and Organic Chemistry (Section of Organic Chemistry), Institute of Computational and Theoretical Chemistry (IQTCUB), Martí i Franquès 1, 08028, Barcelona, Spain.,Present address: Nostrum Biodiscovery, Av. De Josep Tarradellas, 8-10, 08029, Barcelona, Spain
| | - Carme Rovira
- Department of Inorganic and Organic Chemistry (Section of Organic Chemistry), Institute of Computational and Theoretical Chemistry (IQTCUB), Martí i Franquès 1, 08028, Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys, 23, 08010, Barcelona, Spain
| | - Bernd Nidetzky
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 12/1, 8010, Graz, Austria.,Austrian Center of Industrial Biotechnology (acib), Krenngasse 37, 8010, Graz, Austria
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Rapp C, Nidetzky B. Hydride Transfer Mechanism of Enzymatic Sugar Nucleotide C2 Epimerization Probed with a Loose-Fit CDP-Glucose Substrate. ACS Catal 2022; 12:6816-6830. [PMID: 35747200 PMCID: PMC9207888 DOI: 10.1021/acscatal.2c00257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 05/12/2022] [Indexed: 11/29/2022]
Abstract
![]()
Transient oxidation–reduction
through hydride transfer with
tightly bound NAD coenzyme is used by a large class of sugar nucleotide
epimerases to promote configurational inversion of carbon stereocenters
in carbohydrate substrates. A requirement for the epimerases to coordinate
hydride abstraction and re-addition with substrate rotation in the
binding pocket poses a challenge for dynamical protein conformational
selection linked to enzyme catalysis. Here, we studied the thermophilic
C2 epimerase from Thermodesulfatator atlanticus (TaCPa2E) in combination with a slow CDP-glucose
substrate (kcat ≈ 1.0 min–1; 60 °C) to explore the sensitivity of the enzymatic hydride
transfer toward environmental fluctuations affected by temperature
(20–80 °C). We determined noncompetitive primary kinetic
isotope effects (KIE) due to 2H at the glucose C2 and showed
that a normal KIE on the kcat (Dkcat) reflects isotope sensitivity of
the hydrogen abstraction to enzyme-NAD+ in a rate-limiting
transient oxidation. The Dkcat peaked at 40 °C was 6.1 and decreased to 2.1 at low (20 °C)
and 3.3 at high temperature (80 °C). The temperature profiles
for kcat with the 1H and 2H substrate showed a decrease in the rate below a dynamically
important breakpoint (∼40 °C), suggesting an equilibrium
shift to an impaired conformational landscape relevant for catalysis
in the low-temperature region. Full Marcus-like model fits of the
rate and KIE profiles provided evidence for a high-temperature reaction
via low-frequency conformational sampling associated with a broad
distribution of hydride donor–acceptor distances (long-distance
population centered at 3.31 ± 0.02 Å), only poorly suitable
for quantum mechanical tunneling. Collectively, dynamical characteristics
of TaCPa2E-catalyzed hydride transfer during transient
oxidation of CDP-glucose reveal important analogies to mechanistically
simpler enzymes such as alcohol dehydrogenase and dihydrofolate reductase.
A loose-fit substrate (in TaCPa2E) resembles structural
variants of these enzymes by extensive dynamical sampling to balance
conformational flexibility and catalytic efficiency.
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Affiliation(s)
- Christian Rapp
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
| | - Bernd Nidetzky
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
- Austrian Centre of Industrial Biotechnology (ACIB), Petersgasse 14, 8010 Graz, Austria
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Grossman AS, Escobar CA, Mans EJ, Mucci NC, Mauer TJ, Jones KA, Moore CC, Abraham PE, Hettich RL, Schneider L, Campagna SR, Forest KT, Goodrich-Blair H. A Surface Exposed, Two-Domain Lipoprotein Cargo of a Type XI Secretion System Promotes Colonization of Host Intestinal Epithelia Expressing Glycans. Front Microbiol 2022; 13:800366. [PMID: 35572647 PMCID: PMC9100927 DOI: 10.3389/fmicb.2022.800366] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 03/07/2022] [Indexed: 11/17/2022] Open
Abstract
The only known required component of the newly described Type XI secretion system (TXISS) is an outer membrane protein (OMP) of the DUF560 family. TXISSOMPs are broadly distributed across proteobacteria, but properties of the cargo proteins they secrete are largely unexplored. We report biophysical, histochemical, and phenotypic evidence that Xenorhabdus nematophila NilC is surface exposed. Biophysical data and structure predictions indicate that NilC is a two-domain protein with a C-terminal, 8-stranded β-barrel. This structure has been noted as a common feature of TXISS effectors and may be important for interactions with the TXISSOMP. The NilC N-terminal domain is more enigmatic, but our results indicate it is ordered and forms a β-sheet structure, and bioinformatics suggest structural similarities to carbohydrate-binding proteins. X. nematophila NilC and its presumptive TXISSOMP partner NilB are required for colonizing the anterior intestine of Steinernema carpocapsae nematodes: the receptacle of free-living, infective juveniles and the anterior intestinal cecum (AIC) in juveniles and adults. We show that, in adult nematodes, the AIC expresses a Wheat Germ Agglutinin (WGA)-reactive material, indicating the presence of N-acetylglucosamine or N-acetylneuraminic acid sugars on the AIC surface. A role for this material in colonization is supported by the fact that exogenous addition of WGA can inhibit AIC colonization by X. nematophila. Conversely, the addition of exogenous purified NilC increases the frequency with which X. nematophila is observed at the AIC, demonstrating that abundant extracellular NilC can enhance colonization. NilC may facilitate X. nematophila adherence to the nematode intestinal surface by binding to host glycans, it might support X. nematophila nutrition by cleaving sugars from the host surface, or it might help protect X. nematophila from nematode host immunity. Proteomic and metabolomic analyses of wild type X. nematophila compared to those lacking nilB and nilC revealed differences in cell wall and secreted polysaccharide metabolic pathways. Additionally, purified NilC is capable of binding peptidoglycan, suggesting that periplasmic NilC may interact with the bacterial cell wall. Overall, these findings support a model that NilB-regulated surface exposure of NilC mediates interactions between X. nematophila and host surface glycans during colonization. This is a previously unknown function for a TXISS.
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Affiliation(s)
- Alex S. Grossman
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Cristian A. Escobar
- Department of Bacteriology, The University of Wisconsin–Madison, Madison, WI, United States
| | - Erin J. Mans
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Nicholas C. Mucci
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Terra J. Mauer
- Department of Bacteriology, The University of Wisconsin–Madison, Madison, WI, United States
| | - Katarina A. Jones
- Department of Chemistry, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Cameron C. Moore
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Paul E. Abraham
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Robert L. Hettich
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Liesel Schneider
- Department of Animal Sciences, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Shawn R. Campagna
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Biological and Small Molecule Mass Spectrometry Core, The University of Tennessee, Knoxville, Knoxville, TN, United States
- The University of Tennessee Oak Ridge Innovation Institute, Knoxville, TN, United States
| | - Katrina T. Forest
- Department of Bacteriology, The University of Wisconsin–Madison, Madison, WI, United States
- Katrina T. Forest,
| | - Heidi Goodrich-Blair
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
- Department of Bacteriology, The University of Wisconsin–Madison, Madison, WI, United States
- *Correspondence: Heidi Goodrich-Blair,
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Overdominance at the Gene Expression Level Plays a Critical Role in the Hybrid Root Growth of Brassica napus. Int J Mol Sci 2021; 22:ijms22179246. [PMID: 34502153 PMCID: PMC8431428 DOI: 10.3390/ijms22179246] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/20/2021] [Accepted: 08/23/2021] [Indexed: 01/12/2023] Open
Abstract
Despite heterosis contributing to genetic improvements in crops, root growth heterosis in rapeseed plants is poorly understood at the molecular level. The current study was performed to discover key differentially expressed genes (DEGs) related to heterosis in two hybrids with contrasting root growth performance (FO; high hybrid and FV; low hybrid) based on analysis of the root heterosis effect. Based on comparative transcriptomic analysis, we believe that the overdominance at the gene expression level plays a critical role in hybrid roots’ early biomass heterosis. Our findings imply that a considerable increase in up-regulation of gene expression underpins heterosis. In the FO hybrid, high expression of DEGs overdominant in the starch/sucrose and galactose metabolic pathways revealed a link between hybrid vigor and root growth. DEGs linked to auxin, cytokinin, brassinosteroids, ethylene, and abscisic acid were also specified, showing that these hormones may enhance mechanisms of root growth and the development in the FO hybrid. Moreover, transcription factors such as MYB, ERF, bHLH, NAC, bZIP, and WRKY are thought to control downstream genes involved in root growth. Overall, this is the first study to provide a better understanding related to the regulation of the molecular mechanism of heterosis, which assists in rapeseed growth and yield improvement.
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Expanding the Enzyme Repertoire for Sugar Nucleotide Epimerization: The CDP-Tyvelose 2-Epimerase from Thermodesulfatator atlanticus for Glucose/Mannose Interconversion. Appl Environ Microbiol 2021; 87:AEM.02131-20. [PMID: 33277270 PMCID: PMC7851689 DOI: 10.1128/aem.02131-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Epimerization of sugar nucleotides is central to the structural diversification of monosaccharide building blocks for cellular biosynthesis. Epimerase applicability to carbohydrate synthesis can be limited, however, by the high degree of substrate specificity exhibited by most sugar nucleotide epimerases. Here, we discovered a promiscuous type of CDP-tyvelose 2-epimerase (TyvE)-like enzyme that promotes C2-epimerization in all nucleotide (CDP, UDP, GDP, ADP, TDP)-activated forms of d-glucose. This new epimerase, originating from Thermodesulfatator atlanticus, is a functional homodimer that contains one tightly bound NAD+/subunit and shows optimum activity at 70°C and pH 9.5. The enzyme exhibits a k cat with CDP-dglucose of ∼1.0 min-1 (pH 7.5, 60°C). To characterize the epimerase kinetically and probe its substrate specificity, we developed chemo-enzymatic syntheses for CDP-dmannose, CDP-6-deoxy-dglucose, CDP-3-deoxy-dglucose and CDP-6-deoxy-dxylo-hexopyranos-4-ulose. Attempts to obtain CDP-dparatose and CDP-dtyvelose were not successful. Using high-resolution carbohydrate analytics and in situ NMR to monitor the enzymatic conversions (60°C, pH 7.5), we show that the CDP-dmannose/CDP-dglucose ratio at equilibrium is 0.67 (± 0.1), determined from the kinetic Haldane relationship and directly from the reaction. We further show that deoxygenation at sugar C6 enhances the enzyme activity 5-fold compared to CDP-dglucose whereas deoxygenation at C3 renders the substrate inactive. Phylogenetic analysis places the T. atlanticus epimerase into a distinct subgroup within the sugar nucleotide epimerase family of SDR (short-chain dehydrogenases/reductases), for which the current study now provides the functional context. Collectively, our results expand an emerging toolbox of epimerase-catalyzed reactions for sugar nucleotide synthesis.IMPORTANCE Epimerases of the sugar nucleotide-modifying class of enzymes have attracted considerable interest in carbohydrate (bio)chemistry, for the mechanistic challenges and the opportunities for synthesis involved in the reactions catalyzed. Discovery of new epimerases with expanded scope of sugar nucleotide substrates used is important to promote the mechanistic inquiry and can facilitate the development of new enzyme applications. Here, a CDP-tyvelose 2-epimerase-like enzyme from Thermodesulfatator atlanticus is shown to catalyze sugar C2 epimerization in CDP-glucose and other nucleotide-activated forms of dglucose. The reactions are new to nature in the context of enzymatic sugar nucleotide modification. The current study explores the substrate scope of the discovered C2-epimerase and, based on modeling, suggests structure-function relationships that may be important for specificity and catalysis.
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Iacovino LG, Savino S, Borg AJE, Binda C, Nidetzky B, Mattevi A. Crystallographic snapshots of UDP-glucuronic acid 4-epimerase ligand binding, rotation, and reduction. J Biol Chem 2020; 295:12461-12473. [PMID: 32661196 DOI: 10.1074/jbc.ra120.014692] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/10/2020] [Indexed: 11/06/2022] Open
Abstract
UDP-glucuronic acid is converted to UDP-galacturonic acid en route to a variety of sugar-containing metabolites. This reaction is performed by a NAD+-dependent epimerase belonging to the short-chain dehydrogenase/reductase family. We present several high-resolution crystal structures of the UDP-glucuronic acid epimerase from Bacillus cereus The geometry of the substrate-NAD+ interactions is finely arranged to promote hydride transfer. The exquisite complementarity between glucuronic acid and its binding site is highlighted by the observation that the unligated cavity is occupied by a cluster of ordered waters whose positions overlap the polar groups of the sugar substrate. Co-crystallization experiments led to a structure where substrate- and product-bound enzymes coexist within the same crystal. This equilibrium structure reveals the basis for a "swing and flip" rotation of the pro-chiral 4-keto-hexose-uronic acid intermediate that results from glucuronic acid oxidation, placing the C4' atom in position for receiving a hydride ion on the opposite side of the sugar ring. The product-bound active site is almost identical to that of the substrate-bound structure and satisfies all hydrogen-bonding requirements of the ligand. The structure of the apoenzyme together with the kinetic isotope effect and mutagenesis experiments further outlines a few flexible loops that exist in discrete conformations, imparting structural malleability required for ligand rotation while avoiding leakage of the catalytic intermediate and/or side reactions. These data highlight the double nature of the enzymatic mechanism: the active site features a high degree of precision in substrate recognition combined with the flexibility required for intermediate rotation.
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Affiliation(s)
- Luca Giacinto Iacovino
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy
| | - Simone Savino
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Graz, Austria
| | - Annika J E Borg
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Graz, Austria
| | - Claudia Binda
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy
| | - Bernd Nidetzky
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Graz, Austria .,Austrian Centre of Industrial Biotechnology, Graz, Austria
| | - Andrea Mattevi
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy
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