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Carrillo JT, Borthakur D. Characterization of a plant S-adenosylmethionine synthetase from Acacia koa. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 210:108618. [PMID: 38631157 DOI: 10.1016/j.plaphy.2024.108618] [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: 12/01/2023] [Revised: 03/05/2024] [Accepted: 04/07/2024] [Indexed: 04/19/2024]
Abstract
The Acacia koa S-adenosylmethionine (SAM) synthetase was identified from transcriptome data and cloned into the T7-expression vector pEt14b. Assays indicate a thermoalkaliphic enzyme which tolerates conditions up to pH 10.5, 55 °C and 3 M KCl. In vitro examples of plant SAM-synthetase activity are scarce, however this study provides supporting evidence that these extremophilic properties may actually be typical for this plant enzyme. Enzyme kinetic constants (Km = 1.44 mM, Kcat = 1.29 s-1, Vmax 170 μM. min-1) are comparable to nonplant SAM-synthetases except that substrate inhibition was not apparent at 10 mM ATP/L-methionine. Methods were explored in this study to reduce feedback inhibition, which is known to limit SAM-synthetase activity in vitro. Four single-point mutation variants of the Acacia koa SAM-synthetase were produced, each with varying degrees of reduced reaction rate, greater sensitivity to product inhibition and loss of thermophilic properties. Although an enhanced mutant was not produced, this study describes the first mutagenesis of a plant SAM-synthetase. Overcoming feedback inhibition was accomplished by the addition of organic solvent to enzyme assays. Acetonitrile, methanol or dimethylformamide, when included as 25% of the assay volume, improved total SAM production by 30-65%.
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Affiliation(s)
- James T Carrillo
- University of Hawaii at Manoa, Department of Molecular Biosciences and Bioengineering, 1955 East-West Road, Agricultural Sciences 218, Honolulu, HI, 96822, USA.
| | - Dulal Borthakur
- University of Hawaii at Manoa, Department of Molecular Biosciences and Bioengineering, 1955 East-West Road, Agricultural Sciences 218, Honolulu, HI, 96822, USA.
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Carrillo JT, Borthakur D. Heterologous expression and characterization of a thermoalkaliphilic SAM-synthetase from giant leucaena (Leucaena leucocephala subsp glabrata). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2022; 181:42-49. [PMID: 35429803 DOI: 10.1016/j.plaphy.2022.04.009] [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: 01/07/2022] [Revised: 04/01/2022] [Accepted: 04/06/2022] [Indexed: 06/14/2023]
Abstract
The cDNA encoding S-adenosylmethionine (SAM) synthetase was isolated from giant leucaena (Leucaena leucocephala subsp. glabrata) root tissue mRNA. Transcriptome data and 5'-RLM-RACE were used to obtain the transcript sequence and clone into the T7-expression vector pEt14b. N-terminal Histidine-tagged recombinant protein was expressed highly in Escherichia coli, purified and characterized by activity assays. A straightforward method using isocratic reverse-phase HPLC analysis (mobile phase: 0.02M o-phosphoric acid) of enzyme assays determined optimal enzyme activity at pH 10.0, 55 °C and 200 mM KCl. In addition to thermophilic activity, giant leucaena SAM-synthetase remains highly active in solutions containing up to 4 M KCl and accepts Na+ to some extent as a substitute for K+, a known required cofactor for SAM-synthetases. The enzyme followed Michaelis-Menten kinetics (Km = 1.82 mM, Kcat = 1.17 s-1, Vmax 243.9 μM. min-1) and was not inhibited by spermidine, spermine or nicotianamine. Giant leucaena SAM-synthetase is a highly tolerant enzyme to extreme conditions, suggesting further studies on plant SAM-synthetases.
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Affiliation(s)
- James T Carrillo
- University of Hawaii at Manoa, Department of Molecular Biosciences and Bioengineering, 1955 East-West Road, Agricultural Sciences 218, Honolulu, HI, 96822, USA.
| | - Dulal Borthakur
- University of Hawaii at Manoa, Department of Molecular Biosciences and Bioengineering, 1955 East-West Road, Agricultural Sciences 218, Honolulu, HI, 96822, USA.
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Yin C, Zheng T, Chang X. Biosynthesis of S-Adenosylmethionine by Magnetically Immobilized Escherichia coli Cells Highly Expressing a Methionine Adenosyltransferase Variant. Molecules 2017; 22:E1365. [PMID: 28820476 PMCID: PMC6152220 DOI: 10.3390/molecules22081365] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Revised: 08/16/2017] [Accepted: 08/16/2017] [Indexed: 11/19/2022] Open
Abstract
S-Adenosylmethionine (SAM) is a natural metabolite having important uses in the treatment of various diseases. To develop a simple and effective way to produce SAM, immobilized Escherichia coli cells highly expressing an engineered variant of methionine adenosyltransferase (MAT) were employed to synthesize SAM. The recombinant I303V MAT variant was successfully produced at approximately 900 mg/L in a 10-L bioreactor and exhibited significantly less product inhibition and had a four-fold higher specific activity (14.2 U/mg) than the wild-type MAT (3.6 U/mg). To reduce the mass transfer resistance, the free whole-cells were permeabilized and immobilized using gellan gum gel as support in the presence of 100 mg/L Fe₃O₄ nanoparticles, and the highest activity (4152.4 U/L support) was obtained, with 78.2% of the activity recovery. The immobilized cells were more stable than the free cells under non-reactive conditions, with a half-life of 9.1 h at 50 °C. Furthermore, the magnetically immobilized cells were employed to produce SAM at a 40-mM scale. The residual activity of the immobilized cells was 67% of its initial activity after 10 reuses, and the conversion rate of ATP was ≥95% in all 10 batches. These results indicated that magnetically immobilized cells should be a promising biocatalyst for the biosynthesis of SAM.
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Affiliation(s)
- Chunli Yin
- School of Biological and Environmental Engineering, Xi'an University, Xi'an 710065, China.
| | - Tao Zheng
- School of Biological and Environmental Engineering, Xi'an University, Xi'an 710065, China.
| | - Xin Chang
- School of Biological and Environmental Engineering, Xi'an University, Xi'an 710065, China.
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Enzymatic Synthesis of S-Adenosylmethionine Using Immobilized Methionine Adenosyltransferase Variants on the 50-mM Scale. Catalysts 2017. [DOI: 10.3390/catal7080238] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
S-adenosylmethionine (SAM), an important metabolite in all living organisms, has been widely used to treat various diseases. To develop a simple and efficient method to produce SAM, an engineered variant of the methionine adenosyltransferase (MAT) from Escherichia coli was investigated for its potential use in the enzymatic synthesis of SAM due to its significantly decreased product inhibition. The recombinant I303V MAT variant was successfully produced at a high level (~800 mg/L) with approximately four-fold higher specific activity than the wild-type MAT. The recombinant I303V MAT was covalently immobilized onto the amino resin and epoxy resin in order to obtain a robust biocatalyst to be used in industrial bioreactors. The immobilized preparation using amino resin exhibited the highest activity coupling yield (~84%), compared with approximately 3% for epoxy resin. The immobilized enzyme was more stable than the soluble enzyme under the reactive conditions, with a half-life of 229.5 h at 37 °C. The KmATP value (0.18 mM) of the immobilized enzyme was ca. two-fold lower than that of the soluble enzyme. Furthermore, the immobilized enzyme showed high operational stability during 10 consecutive 8 h batches, with the substrate adenosine triphosphate (ATP) conversion rate above 95% on the 50-mM scale.
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Han G, Hu X, Wang X. Overexpression of methionine adenosyltransferase inCorynebacterium glutamicumfor production ofS-adenosyl-l-methionine. Biotechnol Appl Biochem 2015; 63:679-689. [DOI: 10.1002/bab.1425] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 07/26/2015] [Indexed: 12/14/2022]
Affiliation(s)
- Guoqiang Han
- State Key Laboratory of Food Science and Technology; Jiangnan University; Wuxi People's Republic of China
- Key Laboratory of Industrial Biotechnology; Ministry of Education; School of Biotechnology; Jiangnan University; Wuxi People's Republic of China
| | - Xiaoqing Hu
- State Key Laboratory of Food Science and Technology; Jiangnan University; Wuxi People's Republic of China
| | - Xiaoyuan Wang
- State Key Laboratory of Food Science and Technology; Jiangnan University; Wuxi People's Republic of China
- Synergetic Innovation Center of Food Safety and Nutrition; Jiangnan University; Wuxi People's Republic of China
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Yao G, Qin X, Chu J, Wu X, Qian J. Expression, purification, and characterization of a recombinant methionine adenosyltransferase pDS16 in Pichia pastoris. Appl Biochem Biotechnol 2013; 172:1241-53. [PMID: 24154832 DOI: 10.1007/s12010-013-0594-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Accepted: 10/07/2013] [Indexed: 11/26/2022]
Abstract
Methionine adenosyltransferase (MAT, EC2.5.1.6) catalyzes the synthesis of S-adenosylmethionine (SAM) using L-methionine and adenosine triphosphate (ATP) as substrates. The mutant MAT pDS16 was obtained through DNA shuffling previously in our lab. Overexpression of pDS16 in Pichia pastoris led to about 65 % increase of MAT activity and SAM accumulation, compared with the strain overexpressing Saccharomyces cerevisiae MAT gene SAM2. Different strategies were tested to facilitate the expression and purification of pDS16. However, addition of the hexahistidine tag to pDS16 was shown to decrease the enzyme activity, and the yeast α-factor signal sequence could not effectivley direct the secretion of pDS16. The intracellular pDS16 was purified by a simple two-step procedure combining an ion exchange and hydrophobic interaction chromatography. Protein purity was verified by sodium dodecyl sulfate polyacrylamide gel electrophoresis to be 93%, with the specific activity of 1.828 U/mg. Two-dimensional electrophoresis revealed pI of ∼5.5. The purified enzyme followed Michaelis kinetics with a Km of 1.72 and 0.85 mM, and Vmax of 1.54 and 1.15 μmol/min/mg for ATP and L-methionine, respectively. pDS16 exhibited optimal activity at pH 8.5 and 45 °C with the requirement of divalent cation Mg(2+) and was slightly stimulated by the monovalent cation K(+). It showed an improved thermostability, about 50% of the enzyme activity was retained even after preincubation at 50 °C for 2 h.
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Affiliation(s)
- Gaofeng Yao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China
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Hu X, Chu J, Zhang S, Zhuang Y. Comparative performance of S-adenosyl-L-methionine biosynthesis and degradation in Pichia pastoris using different promoters and novel consumption inhibitors. Enzyme Microb Technol 2013; 55:94-9. [PMID: 24411450 DOI: 10.1016/j.enzmictec.2013.09.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 08/07/2013] [Accepted: 09/07/2013] [Indexed: 10/26/2022]
Abstract
The yeast Pichia pastoris is a widely used host for recombinant protein expression, and has recently been engineered for whole-cell biocatalysis. The inducible P(AOX) and constitutive P(GAP) promoters are commonly employed. In this study, the S-adenosyl-L-methionine (SAM) biosynthesis and degradation efficiency of two P. pastoris strains were compared, and novel inhibitors that suppress SAM degradation were characterized. The strains exhibited clear physiological differences. P(GAP)-Pichia showed higher transcription and activity of SAM synthetase, and the rapid cell growth led to higher levels of spermidine synthesis from SAM. In contrast, P(AOX)-Pichia synthesized higher levels of glutathione from SAM, and this strain responded to hydrogen peroxide formation during methanol utilization. Aristeromycin proved an efficient inhibitor of SAM degradation in P(AOX)-Pichia; 0.02 mg/L led to a 36.36% reduction in the ratio of glutathionine:SAM, and SAM accumulation was enhanced by 7.74% to 11.83 g/L. Ethanol was an even more efficient inhibitor of SAM consumption in P(GAP)-Pichia; 8 g/L resulted in a 73.68% decrease in the ratio of SPD:SAM, and SAM production was elevated by 54.55% to 0.17 g/L/h.
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Affiliation(s)
- Xiaoqing Hu
- Key Laboratory of Industrial Biotechnology of Ministry of Education, and State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Ju Chu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Siliang Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.
| | - Yingping Zhuang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
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Chu J, Qian J, Zhuang Y, Zhang S, Li Y. Progress in the research of S-adenosyl-l-methionine production. Appl Microbiol Biotechnol 2012; 97:41-9. [DOI: 10.1007/s00253-012-4536-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2012] [Revised: 10/21/2012] [Accepted: 10/22/2012] [Indexed: 12/30/2022]
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Strain improvement for enhanced production of S-adenosyl-L-methionine in Saccharomyces cerevisiae based on ethionine-resistance and SAM synthetase activity. ANN MICROBIOL 2011. [DOI: 10.1007/s13213-011-0389-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Current awareness on yeast. Yeast 2008. [DOI: 10.1002/yea.1558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Hu XQ, Chu J, Zhang Z, Zhang SL, Zhuang YP, Wang YH, Guo MJ, Chen HX, Yuan ZY. Effects of different glycerol feeding strategies on S-adenosyl-l-methionine biosynthesis by PGAP-driven Pichia pastoris overexpressing methionine adenosyltransferase. J Biotechnol 2008; 137:44-9. [DOI: 10.1016/j.jbiotec.2008.04.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2007] [Revised: 04/05/2008] [Accepted: 04/14/2008] [Indexed: 10/22/2022]
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