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Ferreira EA, Pacheco CC, Rodrigues JS, Pinto F, Lamosa P, Fuente D, Urchueguía J, Tamagnini P. Heterologous Production of Glycine Betaine Using Synechocystis sp. PCC 6803-Based Chassis Lacking Native Compatible Solutes. Front Bioeng Biotechnol 2022; 9:821075. [PMID: 35071221 PMCID: PMC8777070 DOI: 10.3389/fbioe.2021.821075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 12/15/2021] [Indexed: 12/04/2022] Open
Abstract
Among compatible solutes, glycine betaine has various applications in the fields of nutrition, pharmaceuticals, and cosmetics. Currently, this compound can be extracted from sugar beet plants or obtained by chemical synthesis, resulting in low yields or high carbon footprint, respectively. Hence, in this work we aimed at exploring the production of glycine betaine using the unicellular cyanobacterium Synechocystis sp. PCC 6803 as a photoautotrophic chassis. Synechocystis mutants lacking the native compatible solutes sucrose or/and glucosylglycerol-∆sps, ∆ggpS, and ∆sps∆ggpS-were generated and characterized. Under salt stress conditions, the growth was impaired and accumulation of glycogen decreased by ∼50% whereas the production of compatible solutes and extracellular polymeric substances (capsular and released ones) increased with salinity. These mutants were used as chassis for the implementation of a synthetic device based on the metabolic pathway described for the halophilic cyanobacterium Aphanothece halophytica for the production of the compatible solute glycine betaine. Transcription of ORFs comprising the device was shown to be stable and insulated from Synechocystis' native regulatory network. Production of glycine betaine was achieved in all chassis tested, and was shown to increase with salinity. The introduction of the glycine betaine synthetic device into the ∆ggpS background improved its growth and enabled survival under 5% NaCl, which was not observed in the absence of the device. The maximum glycine betaine production [64.29 µmol/gDW (1.89 µmol/mg protein)] was reached in the ∆ggpS chassis grown under 3% NaCl. Taking into consideration this production under seawater-like salinity, and the identification of main key players involved in the carbon fluxes, this work paves the way for a feasible production of this, or other compatible solutes, using optimized Synechocystis chassis in a pilot-scale.
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Affiliation(s)
- Eunice A. Ferreira
- I3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- ICBAS—Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Catarina C. Pacheco
- I3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - João S. Rodrigues
- I3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Filipe Pinto
- I3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Pedro Lamosa
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Oeiras, Portugal
| | - David Fuente
- Instituto de Aplicaciones de las Tecnologías de la Información y de las Comunicaciones Avanzadas, Universitat Politècnica de València, València, Spain
| | - Javier Urchueguía
- Instituto de Aplicaciones de las Tecnologías de la Información y de las Comunicaciones Avanzadas, Universitat Politècnica de València, València, Spain
| | - Paula Tamagnini
- I3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
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Investigations of Dimethylglycine, Glycine Betaine, and Ectoine Uptake by a Betaine-Carnitine-Choline Transporter Family Transporter with Diverse Substrate Specificity in Vibrio Species. J Bacteriol 2020; 202:JB.00314-20. [PMID: 32817090 DOI: 10.1128/jb.00314-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 08/06/2020] [Indexed: 01/08/2023] Open
Abstract
Fluctuations in osmolarity are one of the most prevalent stresses to which bacteria must adapt, both hypo- and hyperosmotic conditions. Most bacteria cope with high osmolarity by accumulating compatible solutes (osmolytes) in the cytoplasm to maintain the turgor pressure of the cell. Vibrio parahaemolyticus, a halophile, utilizes at least six compatible solute transporters for the uptake of osmolytes: two ABC family ProU transporters and four betaine-carnitine-choline transporter (BCCT) family transporters. The full range of compatible solutes transported by this species has yet to be determined. Using an osmolyte phenotypic microarray plate for growth analyses, we expanded the known osmolytes used by V. parahaemolyticus to include N,N-dimethylglycine (DMG), among others. Growth pattern analysis of four triple-bccT mutants, possessing only one functional BCCT, indicated that BccT1 (VP1456), BccT2 (VP1723), and BccT3 (VP1905) transported DMG. BccT1 was unusual in that it could take up both compounds with methylated head groups (glycine betaine [GB], choline, and DMG) and cyclic compounds (ectoine and proline). Bioinformatics analysis identified the four coordinating amino acid residues for GB in the BccT1 protein. In silico modeling analysis demonstrated that GB, DMG, and ectoine docked in the same binding pocket in BccT1. Using site-directed mutagenesis, we showed that a strain with all four residues mutated resulted in the loss of uptake of GB, DMG, and ectoine. We showed that three of the four residues were essential for ectoine uptake, whereas only one of the residues was important for GB uptake. Overall, we have demonstrated that DMG is a highly effective compatible solute for Vibrio species and have elucidated the amino acid residues in BccT1 that are important for the coordination of GB, DMG, and ectoine transport.IMPORTANCE Vibrio parahaemolyticus possesses at least six osmolyte transporters, which allow the bacterium to adapt to high-salinity conditions. In this study, we identified several additional osmolytes that were utilized by V. parahaemolyticus We demonstrated that the compound DMG, which is present in the marine environment, was a highly effective osmolyte for Vibrio species. We determined that DMG is transported via BCCT family carriers, which have not been shown previously to take up this compound. BccT1 was a carrier for GB, DMG, and ectoine, and we identified the amino acid residues essential for the coordination of these compounds. The data suggest that for BccT1, GB is more easily accommodated than ectoine in the transporter binding pocket.
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Casaitė V, Povilonienė S, Meškienė R, Rutkienė R, Meškys R. Studies of dimethylglycine oxidase isoenzymes in Arthrobacter globiformis cells. Curr Microbiol 2010; 62:1267-73. [PMID: 21188587 DOI: 10.1007/s00284-010-9852-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Accepted: 12/16/2010] [Indexed: 10/18/2022]
Abstract
Glycine betaine (GB) could be used by Arthrobacter globiformis cells as a sole carbon source. The cells took up this molecule in the low as well as in the high salinity medium. Addition of GB to the mineral medium with high salt concentration revealed that GB was also used as an osmoprotectant. Dimethylglycine oxidase (DMGO) was involved in the catabolism of GB. Two genes for DMGO were detected in a cloned 26267 bp fragment of A. globiformis DNA. The genes involved in the tetrahydrofolate-dependent assimilation of methyl groups were located nearby the two of DMGO genes. Both cloned A. globiformis DMGO were active. The activity of DMGO was detected in A. globiformis cells and it depended on the addition of GB and the salinity of the medium. Reverse transcription-PCR demonstrated that the addition of GB influenced the transcription of dmg genes.
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Affiliation(s)
- Vida Casaitė
- Department of Molecular Microbiology and Biotechnology, Institute of Biochemistry, Vilnius University, Vilnius, Lithuania.
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Soontharapirakkul K, Incharoensakdi A. Na+-stimulated ATPase of alkaliphilic halotolerant cyanobacterium Aphanothece halophytica translocates Na+ into proteoliposomes via Na+ uniport mechanism. BMC BIOCHEMISTRY 2010; 11:30. [PMID: 20691102 PMCID: PMC2928168 DOI: 10.1186/1471-2091-11-30] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Accepted: 08/07/2010] [Indexed: 11/10/2022]
Abstract
Background When cells are exposed to high salinity conditions, they develop a mechanism to extrude excess Na+ from cells to maintain the cytoplasmic Na+ concentration. Until now, the ATPase involved in Na+ transport in cyanobacteria has not been characterized. Here, the characterization of ATPase and its role in Na+ transport of alkaliphilic halotolerant Aphanothece halophytica were investigated to understand the survival mechanism of A. halophytica under high salinity conditions. Results The purified enzyme catalyzed the hydrolysis of ATP in the presence of Na+ but not K+, Li+ and Ca2+. The apparent Km values for Na+ and ATP were 2.0 and 1.2 mM, respectively. The enzyme is likely the F1F0-ATPase based on the usual subunit pattern and the protection against N,N'-dicyclohexylcarbodiimide inhibition of ATPase activity by Na+ in a pH-dependent manner. Proteoliposomes reconstituted with the purified enzyme could take up Na+ upon the addition of ATP. The apparent Km values for this uptake were 3.3 and 0.5 mM for Na+ and ATP, respectively. The mechanism of Na+ transport mediated by Na+-stimulated ATPase in A. halophytica was revealed. Using acridine orange as a probe, alkalization of the lumen of proteoliposomes reconstituted with Na+-stimulated ATPase was observed upon the addition of ATP with Na+ but not with K+, Li+ and Ca2+. The Na+- and ATP-dependent alkalization of the proteoliposome lumen was stimulated by carbonyl cyanide m - chlorophenylhydrazone (CCCP) but was inhibited by a permeant anion nitrate. The proteoliposomes showed both ATPase activity and ATP-dependent Na+ uptake activity. The uptake of Na+ was enhanced by CCCP and nitrate. On the other hand, both CCCP and nitrate were shown to dissipate the preformed electric potential generated by Na+-stimulated ATPase of the proteoliposomes. Conclusion The data demonstrate that Na+-stimulated ATPase from A. halophytica, a likely member of F-type ATPase, functions as an electrogenic Na+ pump which transports only Na+ upon hydrolysis of ATP. A secondary event, Na+- and ATP-dependent H+ efflux from proteoliposomes, is driven by the electric potential generated by Na+-stimulated ATPase.
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Li KT, Liu DH, Li YL, Chu J, Wang YH, Zhuang YP, Zhang SL. Improved large-scale production of vitamin B12 by Pseudomonas denitrificans with betaine feeding. BIORESOURCE TECHNOLOGY 2008; 99:8516-8520. [PMID: 18440227 DOI: 10.1016/j.biortech.2008.03.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2008] [Revised: 03/11/2008] [Accepted: 03/11/2008] [Indexed: 05/26/2023]
Abstract
The strategy of betaine control for vitamin B12 large-scale fermentation by Pseudomonas denitrificans was investigated in this paper. The results obtained in shake-flask experiments demonstrated that betaine could greatly stimulate vitamin B12 biosynthesis but had an inhibition to cell growth. Based on the influence of betaine on the fermentation of P. denitrificans, betaine feeding was a beneficial strategy to solve the inconsistency between cell growth and vitamin B12 production. As a result, an effective and economical strategy of betaine feeding was established for vitamin B12 fermentation in 120-m3 fermenter, in which betaine was continuously fed to maintain betaine concentration of the broth at the range of 5-7g/l during 50-140h of fermentation.
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Affiliation(s)
- Kun-Tai Li
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China; College of Biological Science and Technology, Jiangxi Agricultural University, Nanchang 330045, China
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Vargas C, Jebbar M, Carrasco R, Blanco C, Calderón MI, Iglesias-Guerra F, Nieto JJ. Ectoines as compatible solutes and carbon and energy sources for the halophilic bacterium Chromohalobacter salexigens. J Appl Microbiol 2006; 100:98-107. [PMID: 16405689 DOI: 10.1111/j.1365-2672.2005.02757.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS To investigate the catabolism of ectoine and hydroxyectoine, which are the major compatible solutes synthesized by Chromohalobacter salexigens. METHODS AND RESULTS Growth curves performed in M63 minimal medium with low (0.75 mol l(-1) NaCl), optimal (1.5 mol l(-1) NaCl) or high (2.5 mol l(-1) NaCl) salinity revealed that betaine and ectoines were used as substrate for growth at optimal and high salt. Ectoine transport was maximal at optimal salinity, and showed 3- and 1.5-fold lower values at low and high salinity respectively. The salt-sensitive ectA mutant CHR62 showed an ectoine transport rate 6.8-fold higher than that of the wild type. Incubation of C. salexigens in a mixture of glucose and ectoine resulted in a biphasic growth pattern. However, CO(2) production due to ectoine catabolism was lower, but not completely abolished, in the presence of glucose. When used as the sole carbon source, glycine betaine effectively inhibited ectoine and hydroxyectoine synthesis at any salinity. CONCLUSIONS The catabolic pathways for ectoine and hydroxyectoine in C. salexigens operate at optimal and high (although less efficiently) salinity. Endogenous ectoine(s) may repress its own transport. Ectoine utilization was only partially repressed by glucose. Betaine, when used as carbon source, suppresses synthesis of ectoines even under high osmolarity conditions. SIGNIFICANCE AND IMPACT OF THE STUDY This study is a previous step to the subsequent isolation and manipulation of the catabolic genes, so as to generate strains with enhanced production of ectoine and hydroxyectoine.
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Affiliation(s)
- C Vargas
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Seville, Seville, Spain
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Incharoensakdi A, Laloknam S. Nitrate uptake in the halotolerant cyanobacterium Aphanothece halophytica is energy-dependent driven by DeltapH. BMB Rep 2005; 38:468-73. [PMID: 16053714 DOI: 10.5483/bmbrep.2005.38.4.468] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The energetics of nitrate uptake by intact cells of the halotolerant cyanobacterium Aphanothece halophytica were investigated. Nitrate uptake was inhibited by various protonophores suggesting the coupling of nitrate uptake to the proton motive force. An artificially-generated pH gradient across the membrane (DeltapH) caused an increase of nitrate uptake. In contrast, the suppression of DeltapH resulted in a decrease of nitrate uptake. The increase of external pH also resulted in an enhancement of nitrate uptake. The generation of the electrical potential across the membrane (Deltapsi) resulted in no elevation of the rate of nitrate uptake. On the other hand, the valinomycin-mediated dissipation of Deltapsi caused no depression of the rate of nitrate uptake. Thus, it is unlikely that Deltapsi participated in the energization of the uptake of nitrate. However, Na(+)-gradient across the membrane was suggested to play a role in nitrate uptake since monensin which collapses Na(+)-gradient strongly inhibited nitrate uptake. Exogenously added glucose and lactate stimulated nitrate uptake in the starved cells. N, N'-dicyclohexylcarbodiimide, an inhibitor of ATPase, could alsoinhibit nitrate uptake suggesting that ATP hydrolysis was required for nitrate uptake. All these results indicate that nitrate uptake in A. halophytica is ATP-dependent, driven by DeltapH and Na(+)-gradient.
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Affiliation(s)
- Aran Incharoensakdi
- Department of Biochemistry and Program of Biotechnology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
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Lee MB, Blunt JW, Lever M, George PM. A nuclear-magnetic-resonance-based assay for betaine-homocysteine methyltransferase activity. Anal Biochem 2005; 330:199-205. [PMID: 15203325 DOI: 10.1016/j.ab.2004.03.069] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2003] [Indexed: 10/26/2022]
Abstract
Betaine-homocysteine methyltransferase (BHMT) activity can be measured directly and kinetically by (1)H-nuclear magnetic resonance spectroscopy. The disappearance of substrates and the formation of products are monitored simultaneously. Alternative substrates, separately and when mixed with glycine betaine, can also be monitored. Each assay can be completed in 1h. Using 2mM glycine betaine and homocysteine as substrates in 20 mM phosphate buffer (pH 7.5) and measuring the production of N,N-dimethylglycine, the CV is 6.3% (n=6) and the detection limit is 6 nkatal. An endpoint assay for BHMT activity was also developed, by measuring the N,N-dimethylglycine produced after incubation with 2 mM glycine betaine and homocysteine (CV=5.3%, n = 6) with a detection limit of 2 nkatal. These assays were used to show that the natural betaines trigonelline, proline betaine, arsenobetaine, and l-carnitine are neither substrates nor significant inhibitors of rat liver BHMT, that the thetins dimethylthetin and dimethylsulfoniopropionate are substrates and inhibit methyl transfer from glycine betaine, and that the K(m) for glycine betaine is 0.19+/-0.03 mM with a V(max) of 17+/-0.7 nMol min(-1) mg(-1).
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Affiliation(s)
- Martin B Lee
- Biochemistry Unit, Canterbury Health Laboratories, PO Box 151, Christchurch, New Zealand.
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Delgado-Reyes CV, Garrow TA. High sodium chloride intake decreases betaine-homocysteine S-methyltransferase expression in guinea pig liver and kidney. Am J Physiol Regul Integr Comp Physiol 2004; 288:R182-7. [PMID: 15331385 DOI: 10.1152/ajpregu.00406.2004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Betaine-homocysteine S-methyltransferase (BHMT) is the only enzyme known to catabolize betaine. In addition to being a substrate for BHMT, betaine also functions as an osmoprotectant that accumulates in the kidney medulla under conditions of high extracellular osmolarity. The mechanisms that regulate the partitioning of betaine between its use as a methyl donor and its accumulation as an osmoprotectant are not completely understood. The aim of this study was to determine whether BHMT expression is regulated by salt intake. This report shows that guinea pigs express BHMT in the liver, kidney, and pancreas and that the steady-state levels of BHMT mRNA in kidney and liver decrease 68% and 93% in guinea pigs consuming tap water containing high levels of salt compared with animals provided untreated tap water. The animals consuming the salt water also had approximately 50% less BHMT activity in the liver and kidney, and steady-state protein levels decreased approximately 30% in both organs. Pancreatic BHMT activity and protein levels were unaffected by the high salt treatment. The complex mechanisms involved in the downregulation of hepatic and renal BHMT expression in guinea pigs drinking salt water remain to be clarified, but the physiological significance of this downregulation may be to expedite the transport and accumulation of betaine into the kidney medulla under conditions of high extracellular osmolarity.
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Ferrer JL, Ravanel S, Robert M, Dumas R. Crystal structures of cobalamin-independent methionine synthase complexed with zinc, homocysteine, and methyltetrahydrofolate. J Biol Chem 2004; 279:44235-8. [PMID: 15326182 DOI: 10.1074/jbc.c400325200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cobalamin-independent methionine synthase (MetE) catalyzes the synthesis of methionine by a direct transfer of the methyl group of N5-methyltetrahydrofolate (CH3-H2PteGlun) to the sulfur atom of homocysteine (Hcy). We report here the first crystal structure of this metalloenzyme under different forms, free or complexed with the Hcy and folate substrates. The Arabidopsis thaliana MetE (AtMetE) crystals reveal a monomeric structure built by two (betaalpha)8 barrels making a deep groove at their interface. The active site is located at the surface of the C-terminal domain, facing the large interdomain cleft. Inside the active site, His647, Cys649, and Cys733 are involved in zinc coordination, whereas Asp605, Ile437, and Ser439 interact with Hcy. Opposite the zinc/Hcy binding site, a cationic loop (residues 507-529) belonging to the C-terminal domain anchors the first glutamyl residue of CH3-H4PteGlu5. The pterin moiety of CH3-H4PteGlu5 is stacked with Trp567, enabling the N5-methyl group to protrude in the direction of the zinc atom. These data suggest a structural role of the N-terminal domain of AtMetE in the stabilization of loop 507-529 and in the interaction with the poly-glutamate chain of CH3-H4PteGlun. Comparison of AtMetE structures reveals that the addition of Hcy does not lead to a direct coordination of the sulfur atom with zinc but to a reorganization of the zinc binding site with a stronger coordination to Cys649, Cys733, and a water molecule.
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Affiliation(s)
- Jean-Luc Ferrer
- Laboratoire de Cristallogenèse et Cristallographie des Protéines, Institut de Biologie Structurale J.-P. Ebel, 41 rue Jules Horowitz, 38027 Grenoble 1, France.
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Kacprzak MM, Lewandowska I, Matthews RG, Paszewski A. Transcriptional regulation of methionine synthase by homocysteine and choline in Aspergillus nidulans. Biochem J 2003; 376:517-24. [PMID: 12954077 PMCID: PMC1223784 DOI: 10.1042/bj20030747] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2003] [Revised: 08/27/2003] [Accepted: 09/03/2003] [Indexed: 11/17/2022]
Abstract
Roles played by homocysteine and choline in the regulation of MS (methionine synthase) have been examined in fungi. The Aspergillus nidulans metH gene encoding MS was cloned and characterized. Its transcription was not regulated by methionine, but was enhanced by homocysteine and repressed by choline and betaine. MS activity levels were regulated in a similar way. The repression by betaine was due to its metabolic conversion to choline, which was found to be very efficient in A. nidulans. Betaine and choline supplementation stimulated growth of leaky metH mutants apparently by decreasing the demand for methyl groups and thus saving methionine and S -adenosylmethionine. We have also found that homocysteine stimulates transcription of MS-encoding genes in Saccharomyces cerevisiae and Schizosaccharomyces pombe.
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Affiliation(s)
- Magdalena M Kacprzak
- Department of Genetics, Institute of Biochemistry and Biophysics, PAS, Pawinskiego 5a, 02-106 Warsaw, Poland
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Meskys R, Harris RJ, Casaite V, Basran J, Scrutton NS. Organization of the genes involved in dimethylglycine and sarcosine degradation in Arthrobacter spp.: implications for glycine betaine catabolism. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:3390-8. [PMID: 11422368 DOI: 10.1046/j.1432-1327.2001.02239.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The nucleotide sequences of two cloned DNA fragments containing the structural genes of heterotetrameric sarcosine oxidase (soxBDAG) and dimethylglycine dehydrogenase (dmg) from Arthrobater spp. 1-IN and Arthrobacter globiformis, respectively, have been determined. Open reading frames were identified in the soxBDAG operon corresponding to the four subunits of heterotetrameric sarcosine oxidase by comparison with the N-terminal amino-acid sequences and the subunit relative molecular masses of the purified enzyme. Alignment of the deduced sarcosine oxidase amino-acid sequence with amino-acid sequences of functionally related proteins indicated that the arthrobacterial enzyme is highly homologous to sarcosine oxidase from Corynebacterium P-1. Deletion and expression analysis, and alignment of the deduced amino-acid sequence of the dmg gene, showed that dmg encodes a novel dimethylglycine oxidase, which is related to eukaryotic dimethylglycine dehydrogenase, and contains nucleotide-binding, flavinylation and folate-binding motifs. The recombinant dimethylglycine oxidase was purified to homogeneity and characterized. The DNA located upstream and downstream of both the soxBDAG and dmg genes is predicted to encode enzymes involved in the tetrahydrofolate-dependent assimilation of methyl groups. Based on the sequence analysis reported herein, pathways are proposed for glycine betaine catabolism in Arthrobacter species, which involve the identified folate-dependent enzymes.
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Affiliation(s)
- R Meskys
- Laboratory of Molecular Microbiology and Biotechnology, Institute of Biochemistry, Mokslininku 12, Vilnius, Lithuania.
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