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Ferreira EGC, Gomes DF, Delai CV, Barreiros MAB, Grange L, Rodrigues EP, Henning LMM, Barcellos FG, Hungria M. Revealing potential functions of hypothetical proteins induced by genistein in the symbiosis island of Bradyrhizobium japonicum commercial strain SEMIA 5079 (= CPAC 15). BMC Microbiol 2022; 22:122. [PMID: 35513812 PMCID: PMC9069715 DOI: 10.1186/s12866-022-02527-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 04/11/2022] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Bradyrhizobium japonicum strain SEMIA 5079 (= CPAC 15) is a nitrogen-fixing symbiont of soybean broadly used in commercial inoculants in Brazil. Its genome has about 50% of hypothetical (HP) protein-coding genes, many in the symbiosis island, raising questions about their putative role on the biological nitrogen fixation (BNF) process. This study aimed to infer functional roles to 15 HP genes localized in the symbiosis island of SEMIA 5079, and to analyze their expression in the presence of a nod-gene inducer. RESULTS A workflow of bioinformatics tools/databases was established and allowed the functional annotation of the HP genes. Most were enzymes, including transferases in the biosynthetic pathways of cobalamin, amino acids and secondary metabolites that may help in saprophytic ability and stress tolerance, and hydrolases, that may be important for competitiveness, plant infection, and stress tolerance. Putative roles for other enzymes and transporters identified are discussed. Some HP proteins were specific to the genus Bradyrhizobium, others to specific host legumes, and the analysis of orthologues helped to predict roles in BNF. CONCLUSIONS All 15 HP genes were induced by genistein and high induction was confirmed in five of them, suggesting major roles in the BNF process.
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Affiliation(s)
- Everton Geraldo Capote Ferreira
- Londrina State University (UEL), Celso Garcia Cid Road (PR 445), km 380, CEP 86057-970 Londrina, PR Brazil
- Embrapa Soja, Rodovia Carlos João Strass, C.P. 231, CEP 86001-970 Londrina, PR Brazil
| | | | - Caroline Vanzzo Delai
- Federal University of Paraná (UFPR), Estrada dos Pioneiros 2153, CEP 85950-000 Palotina, PR Brazil
| | | | - Luciana Grange
- Federal University of Paraná (UFPR), Estrada dos Pioneiros 2153, CEP 85950-000 Palotina, PR Brazil
| | - Elisete Pains Rodrigues
- Londrina State University (UEL), Celso Garcia Cid Road (PR 445), km 380, CEP 86057-970 Londrina, PR Brazil
| | | | - Fernando Gomes Barcellos
- Londrina State University (UEL), Celso Garcia Cid Road (PR 445), km 380, CEP 86057-970 Londrina, PR Brazil
| | - Mariangela Hungria
- Londrina State University (UEL), Celso Garcia Cid Road (PR 445), km 380, CEP 86057-970 Londrina, PR Brazil
- Embrapa Soja, Rodovia Carlos João Strass, C.P. 231, CEP 86001-970 Londrina, PR Brazil
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Key amino acid residues in homoserine-acetyltransferase from M. tuberculosis give insight into the evolution of MetX family of enzymes - HAT, SAT and HST. Biochimie 2021; 189:13-25. [PMID: 34090964 DOI: 10.1016/j.biochi.2021.05.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 05/23/2021] [Accepted: 05/30/2021] [Indexed: 11/22/2022]
Abstract
Multiple sequence alignment of homoserine-acetyltransferases, serine-acetyltransferases and homoserine-succinyltransferases show they all belong to MetX family, having evolved from a common ancestor by conserving the catalytic site and substrate binding residues. The discrimination in the substrate selection arises due to the presence of substrate-specific residues lining the substrate-binding pocket. Mutation of Ala59 and Gly62 to Gly and Pro respectively in homoserine-acetyltransferase from M. tuberculosis resulted in a serine-acetyltransferase like enzyme as it acetylated both l-homoserine and l-serine. Homoserine-acetyltransferase from M. tuberculosis when mutated at positon 322 where Leu was converted to Arg, resulted in succinylation over acetylation of l-homoserine. Our studies establish the importance of the substrate binding residues in determining the type of activity possessed by MetX family, despite all of them having the same catalytic triad Ser-Asp-His. Hence key residues at the substrate binding pocket dictate whether the given enzyme shows predominant transferase or hydrolase activity.
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Hasebe F. MetW regulates the enzymatic activity of MetX in Pseudomonas. Biosci Biotechnol Biochem 2021; 85:351-358. [PMID: 33604638 DOI: 10.1093/bbb/zbaa044] [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: 08/13/2020] [Accepted: 10/05/2020] [Indexed: 11/13/2022]
Abstract
Methionine is a canonical amino acid. The protein MetX is a homoserine O-acyltransferase utilized in the methionine biosynthetic pathway. The metW gene is found adjacent to the metX gene in some bacteria, but its functions are unclear. In this study, I focused on the function of MetW and MetX from Pseudomonas aeruginosa (PaMetW and PaMetX). I demonstrated that PaMetW interacted with and activated the homoserine O-succinyltransferase (HST) activity of PaMetX. Furthermore, I elucidated that the HST activity of PaMetX in complex with PaMetW was inhibited by the addition of S-adenosyl-l-homocysteine (SAH), although PaMetX alone showed no feedback inhibition. Since PaMetW possesses a glycine-rich sequence annotated as a SAM/SAH binding site, I also investigated the relationship between this glycine-rich sequence and the inhibition caused by SAH. I revealed that alanine mutation of PaMetW Gly24 reduced the inhibitory effect of SAH. These results suggest that MetW is a regulatory protein of MetX.
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Affiliation(s)
- Fumihito Hasebe
- Graduate Division of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan
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Gallardo-Benavente C, Campo-Giraldo JL, Castro-Severyn J, Quiroz A, Pérez-Donoso JM. Genomics Insights into Pseudomonas sp. CG01: An Antarctic Cadmium-Resistant Strain Capable of Biosynthesizing CdS Nanoparticles Using Methionine as S-Source. Genes (Basel) 2021; 12:187. [PMID: 33514061 PMCID: PMC7912247 DOI: 10.3390/genes12020187] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 01/20/2021] [Accepted: 01/22/2021] [Indexed: 12/23/2022] Open
Abstract
Here, we present the draft genome sequence of Pseudomonas sp. GC01, a cadmium-resistant Antarctic bacterium capable of biosynthesizing CdS fluorescent nanoparticles (quantum dots, QDs) employing a unique mechanism involving the production of methanethiol (MeSH) from methionine (Met). To explore the molecular/metabolic components involved in QDs biosynthesis, we conducted a comparative genomic analysis, searching for the genes related to cadmium resistance and sulfur metabolic pathways. The genome of Pseudomonas sp. GC01 has a 4,706,645 bp size with a 58.61% G+C content. Pseudomonas sp. GC01 possesses five genes related to cadmium transport/resistance, with three P-type ATPases (cadA, zntA, and pbrA) involved in Cd-secretion that could contribute to the extracellular biosynthesis of CdS QDs. Furthermore, it exhibits genes involved in sulfate assimilation, cysteine/methionine synthesis, and volatile sulfur compounds catabolic pathways. Regarding MeSH production from Met, Pseudomonas sp. GC01 lacks the genes E4.4.1.11 and megL for MeSH generation. Interestingly, despite the absence of these genes, Pseudomonas sp. GC01 produces high levels of MeSH. This is probably associated with the metC gene that also produces MeSH from Met in bacteria. This work is the first report of the potential genes involved in Cd resistance, sulfur metabolism, and the process of MeSH-dependent CdS QDs bioproduction in Pseudomonas spp. strains.
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Affiliation(s)
- Carla Gallardo-Benavente
- Programa de Doctorado en Ciencias de Recursos Naturales, Universidad de La Frontera, 4780000 Temuco, Chile;
- Centro de Excelencia en Investigación Biotecnológica Aplicada al Medio Ambiente (CIBAMA), Facultad de Ingeniería y Ciencias, Universidad de La Frontera, 4780000 Temuco, Chile
| | - Jessica L. Campo-Giraldo
- BioNanotechnology and Microbiology Lab, Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andres Bello, 8320000 Santiago, Chile;
| | - Juan Castro-Severyn
- Laboratorio de Microbiología Aplicada y Extremófilos, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, 1240000 Antofagasta, Chile;
| | - Andrés Quiroz
- Centro de Excelencia en Investigación Biotecnológica Aplicada al Medio Ambiente (CIBAMA), Facultad de Ingeniería y Ciencias, Universidad de La Frontera, 4780000 Temuco, Chile
- Departamento de Ciencias Químicas y Recursos Naturales, Facultad de Ingeniería y Ciencias, Universidad de La Frontera, 4780000 Temuco, Chile
| | - José M. Pérez-Donoso
- BioNanotechnology and Microbiology Lab, Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andres Bello, 8320000 Santiago, Chile;
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Kulikova VV, Anufrieva NV, Kotlov MI, Morozova EA, Koval VS, Belyi YF, Revtovich SV, Demidkina TV. O-acetylhomoserine sulfhydrylase from Clostridium novyi. Cloning, expression of the gene and characterization of the enzyme. Protein Expr Purif 2020; 180:105810. [PMID: 33338587 DOI: 10.1016/j.pep.2020.105810] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 12/08/2020] [Accepted: 12/13/2020] [Indexed: 11/19/2022]
Abstract
The gene NT01CX_1210 of pathogenic bacterium Clostridium novyi annotated as encoding O-acetylhomoserine sulfhydrylase was cloned and expressed in Escherichia coli. The gene product having O-acetylhomoserine sulfhydrylase activity was purified to homogeneity. The protein showed molecular mass of approximately 184 kDa for the native form and 46 kDa for the subunit. The enzyme catalyzes the γ-substitution reaction of O-acetylhomoserine with maximum activity at pH 7.5. Analysis of C. novyi genome allowed us to suggest that there is only one way for the synthesis of l-methionine in the bacterium. The data obtained may provide the basis for further study of the role of OAHS in Clostridium bacteria and an ascertainment of its mechanism.
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Affiliation(s)
- Vitalia V Kulikova
- Engelhardt Institute of Molecular Biology of the Russian Academy of Sciences, Vavilov Street, 32, Moscow, 119991, Russia.
| | - Natalya V Anufrieva
- Engelhardt Institute of Molecular Biology of the Russian Academy of Sciences, Vavilov Street, 32, Moscow, 119991, Russia
| | - Mikhail I Kotlov
- Engelhardt Institute of Molecular Biology of the Russian Academy of Sciences, Vavilov Street, 32, Moscow, 119991, Russia
| | - Elena A Morozova
- Engelhardt Institute of Molecular Biology of the Russian Academy of Sciences, Vavilov Street, 32, Moscow, 119991, Russia
| | - Vasiliy S Koval
- Engelhardt Institute of Molecular Biology of the Russian Academy of Sciences, Vavilov Street, 32, Moscow, 119991, Russia
| | - Yury F Belyi
- Gamaleya National Research Centre of Epidemiology and Microbiology, Ministry of Health of Russian Federation, Gamaleya Street, 18, Moscow, 123098, Russia
| | - Svetlana V Revtovich
- Engelhardt Institute of Molecular Biology of the Russian Academy of Sciences, Vavilov Street, 32, Moscow, 119991, Russia
| | - Tatyana V Demidkina
- Engelhardt Institute of Molecular Biology of the Russian Academy of Sciences, Vavilov Street, 32, Moscow, 119991, Russia
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MetA (Rv3341) from Mycobacterium tuberculosis H37Rv strain exhibits substrate dependent dual role of transferase and hydrolase activity. Biochimie 2020; 179:113-126. [PMID: 32976971 DOI: 10.1016/j.biochi.2020.09.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/10/2020] [Accepted: 09/13/2020] [Indexed: 02/08/2023]
Abstract
The metA (Rv3341) gene from Mycobacterium tuberculosis H37Rv strain encodes a homoserine-acetyltransferase (HAT) enzyme, also called MetA. This enzyme plays a key role in the biosynthetic pathway of methionine and is a potential target for the development of antimicrobial drugs. Purified MetA showed 40 kDa molecular mass on SDS-PAGE. Manual docking was performed with substrates acetyl-CoA, l-homoserine, and p-nitrophenylacetate using crystal structure coordinates of MetA (PDB ID 6PUX) from M. tuberculosis. Multiple sequence alignment indicated that catalytic triad residues Ser157, Asp320, His350 were conserved across species in acetyltransferases, esterases, and hydrolases. As a conserved pentapeptide, GXSMG belongs to α/β hydrolase superfamily and it shares similarity with esterases and hydrolases from different sources. Hydrolase activity of MetA was tested using (PNPA), N-acetylglycine, N-acetylmethionine and Phe-Gly as substrate. LC-MS confirmed that MetA possessed HAT activity, but no homoserine-succinyltransferase (HST) and serine-acetyltransferase (SAT) activities. Replacing acetyl-CoA with PNPA as acetyl group donor showed a drastic reduction in transferase activity, arising due to the interaction of R227 of the enzyme with PNPA. This could prevent the binding of the second substrate in the right orientation and results in the preferential transfer of the acetyl group to water, thus exhibiting hydrolase rather than transferase activity. In this paper, we report that MetA has both transferase and hydrolase activity depending on the correct orientation of the second substrate and the availability of the amino acids involved in enzyme-substrate interaction.
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Jechalke S, Schierstaedt J, Becker M, Flemer B, Grosch R, Smalla K, Schikora A. Salmonella Establishment in Agricultural Soil and Colonization of Crop Plants Depend on Soil Type and Plant Species. Front Microbiol 2019; 10:967. [PMID: 31156568 PMCID: PMC6529577 DOI: 10.3389/fmicb.2019.00967] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 04/16/2019] [Indexed: 12/20/2022] Open
Abstract
Human pathogenic bacteria, such as Salmonella enterica, are able to colonize crop plants. So far, not much is known about biotic and abiotic factors influencing this colonization in field soil. This understanding, however, is imperative for the provision of safe fresh produce to the consumer. In this study, we investigated the effects of soil type, organic fertilization, plant species and the way of Salmonella entry into the plant production system, on the survival of S. enterica in soil as well as the colonization of plants. The selected S. enterica serovar Typhimurium strain 14028s, S. Typhimurium strain LT2 and S. Senftenberg were able to persist in soil for several weeks. Salmonella's persistence in soil was prolonged in loamy, if compared to sandy soil, and when applied together with organic fertilizer. The leaves of lettuce and corn salad were colonized by S. enterica providing evidence for internalization from the soil via the root. Colonization rates were affected by soil type, plant species and S. enterica strain. Overall, S. enterica was detected in leaves of 0.5-0.9% of the plants, while lettuce was more frequently colonized than corn salad. Plants grown in sandy soil were more often colonized than plants grown in loamy soil. After spray inoculation, S. enterica could be detected on and in leaves for several weeks by cultivation-depending methods, confirmed by confocal microscopy using GFP-labeled S. Typhimurium 14028s. On the one hand, transcriptome data from S. Typhimurium 14028s assessed in response to lettuce medium or lettuce root exudates showed an upregulation of genes associated with biofilm formation and virulence. On the other hand, lettuce inoculated with S. Typhimurium 14028s showed a strong upregulation of genes associated with plant immune response and genes related to stress response. In summary, these results showed that organic fertilizers can increase the persistence of Salmonella in soil and that soil type and plant species play a crucial role in the interactions between human pathogens and crop plants. This understanding is therefore a starting point for new strategies to provide safe food for the consumer.
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Affiliation(s)
- Sven Jechalke
- Institute for Phytopathology, Justus Liebig University Giessen, Gießen, Germany
| | - Jasper Schierstaedt
- Leibniz Institute of Vegetable and Ornamental Crops, Plant-Microbe Systems, Großbeeren, Germany
| | - Marlies Becker
- Federal Research Centre for Cultivated Plants, Julius Kühn-Institut (JKI), Institute for Epidemiology and Pathogen Diagnostics, Braunschweig, Germany
| | - Burkhardt Flemer
- Leibniz Institute of Vegetable and Ornamental Crops, Plant-Microbe Systems, Großbeeren, Germany
| | - Rita Grosch
- Leibniz Institute of Vegetable and Ornamental Crops, Plant-Microbe Systems, Großbeeren, Germany
| | - Kornelia Smalla
- Federal Research Centre for Cultivated Plants, Julius Kühn-Institut (JKI), Institute for Epidemiology and Pathogen Diagnostics, Braunschweig, Germany
| | - Adam Schikora
- Federal Research Centre for Cultivated Plants, Julius Kühn-Institut (JKI), Institute for Epidemiology and Pathogen Diagnostics, Braunschweig, Germany
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Epoxyalkane:Coenzyme M Transferase Gene Diversity and Distribution in Groundwater Samples from Chlorinated-Ethene-Contaminated Sites. Appl Environ Microbiol 2016; 82:3269-3279. [PMID: 27016563 DOI: 10.1128/aem.00673-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 03/17/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Epoxyalkane:coenzyme M transferase (EaCoMT) plays a critical role in the aerobic biodegradation and assimilation of alkenes, including ethene, propene, and the toxic chloroethene vinyl chloride (VC). To improve our understanding of the diversity and distribution of EaCoMT genes in the environment, novel EaCoMT-specific terminal-restriction fragment length polymorphism (T-RFLP) and nested-PCR methods were developed and applied to groundwater samples from six different contaminated sites. T-RFLP analysis revealed 192 different EaCoMT T-RFs. Using clone libraries, we retrieved 139 EaCoMT gene sequences from these samples. Phylogenetic analysis revealed that a majority of the sequences (78.4%) grouped with EaCoMT genes found in VC- and ethene-assimilating Mycobacterium strains and Nocardioides sp. strain JS614. The four most-abundant T-RFs were also matched with EaCoMT clone sequences related to Mycobacterium and Nocardioides strains. The remaining EaCoMT sequences clustered within two emergent EaCoMT gene subgroups represented by sequences found in propene-assimilating Gordonia rubripertincta strain B-276 and Xanthobacter autotrophicus strain Py2. EaCoMT gene abundance was positively correlated with VC and ethene concentrations at the sites studied. IMPORTANCE The EaCoMT gene plays a critical role in assimilation of short-chain alkenes, such as ethene, VC, and propene. An improved understanding of EaCoMT gene diversity and distribution is significant to the field of bioremediation in several ways. The expansion of the EaCoMT gene database and identification of incorrectly annotated EaCoMT genes currently in the database will facilitate improved design of environmental molecular diagnostic tools and high-throughput sequencing approaches for future bioremediation studies. Our results further suggest that potentially significant aerobic VC degraders in the environment are not well represented in pure culture. Future research should aim to isolate and characterize aerobic VC-degrading bacteria from these underrepresented groups.
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Crystal structure of the homocysteine methyltransferase MmuM from Escherichia coli. Biochem J 2015; 473:277-84. [PMID: 26564203 DOI: 10.1042/bj20150980] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 11/12/2015] [Indexed: 01/11/2023]
Abstract
Homocysteine S-methyltransferases (HMTs, EC 2.1.1.0) catalyse the conversion of homocysteine to methionine using S-methylmethionine or S-adenosylmethionine as the methyl donor. HMTs play an important role in methionine biosynthesis and are widely distributed among micro-organisms, plants and animals. Additionally, HMTs play a role in metabolite repair of S-adenosylmethionine by removing an inactive diastereomer from the pool. The mmuM gene product from Escherichia coli is an archetypal HMT family protein and contains a predicted zinc-binding motif in the enzyme active site. In the present study, we demonstrate X-ray structures for MmuM in oxidized, apo and metallated forms, representing the first such structures for any member of the HMT family. The structures reveal a metal/substrate-binding pocket distinct from those in related enzymes. The presented structure analysis and modelling of co-substrate interactions provide valuable insight into the function of MmuM in both methionine biosynthesis and cofactor repair.
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Site-Specific Ser/Thr/Tyr Phosphoproteome of Sinorhizobium meliloti at Stationary Phase. PLoS One 2015; 10:e0139143. [PMID: 26401955 PMCID: PMC4581636 DOI: 10.1371/journal.pone.0139143] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 09/08/2015] [Indexed: 11/19/2022] Open
Abstract
Sinorhizobium meliloti, a facultative microsymbiont of alfalfa, should fine-tune its cellular processes to live saprophytically in soils characterized with limited nutrients and diverse stresses. In this study, TiO2 enrichment and LC-MS/MS were used to uncover the site-specific Ser/Thr/Tyr phosphoproteome of S. meliloti in minimum medium at stationary phase. There are a total of 96 unique phosphorylated sites, with a Ser/Thr/Tyr distribution of 63:28:5, in 77 proteins. Phosphoproteins identified in S. meliloti showed a wide distribution pattern regarding to functional categories, such as replication, transcription, translation, posttranslational modification, transport and metabolism of amino acids, carbohydrate, inorganic ion, succinoglycan etc. Ser/Thr/Tyr phosphosites identified within the conserved motif in proteins of key cellular function indicate a crucial role of phosphorylation in modulating cellular physiology. Moreover, phosphorylation in proteins involved in processes related to rhizobial adaptation was also discussed, such as those identified in SMa0114 and PhaP2 (polyhydroxybutyrate synthesis), ActR (pH stress and microaerobic adaption), SupA (potassium stress), chaperonin GroEL2 (viability and potentially symbiosis), and ExoP (succinoglycan synthesis and secretion). These Ser/Thr/Tyr phosphosites identified herein would be helpful for our further investigation and understanding of the role of phosphorylation in rhizobial physiology.
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Leyn SA, Suvorova IA, Kholina TD, Sherstneva SS, Novichkov PS, Gelfand MS, Rodionov DA. Comparative genomics of transcriptional regulation of methionine metabolism in Proteobacteria. PLoS One 2014; 9:e113714. [PMID: 25411846 PMCID: PMC4239095 DOI: 10.1371/journal.pone.0113714] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 10/28/2014] [Indexed: 12/20/2022] Open
Abstract
Methionine metabolism and uptake genes in Proteobacteria are controlled by a variety of RNA and DNA regulatory systems. We have applied comparative genomics to reconstruct regulons for three known transcription factors, MetJ, MetR, and SahR, and three known riboswitch motifs, SAH, SAM-SAH, and SAM_alpha, in ∼ 200 genomes from 22 taxonomic groups of Proteobacteria. We also identified two novel regulons: a SahR-like transcription factor SamR controlling various methionine biosynthesis genes in the Xanthomonadales group, and a potential RNA regulatory element with terminator-antiterminator mechanism controlling the metX or metZ genes in beta-proteobacteria. For each analyzed regulator we identified the core, taxon-specific and genome-specific regulon members. By analyzing the distribution of these regulators in bacterial genomes and by comparing their regulon contents we elucidated possible evolutionary scenarios for the regulation of the methionine metabolism genes in Proteobacteria.
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Affiliation(s)
- Semen A. Leyn
- A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | - Inna A. Suvorova
- A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | - Tatiana D. Kholina
- Faculty of Bioengineering and Bioinformatics, Moscow State University, Moscow, Russia
| | | | - Pavel S. Novichkov
- Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Mikhail S. Gelfand
- A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
- Faculty of Bioengineering and Bioinformatics, Moscow State University, Moscow, Russia
| | - Dmitry A. Rodionov
- A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
- Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
- * E-mail:
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Siewert C, Hess WR, Duduk B, Huettel B, Reinhardt R, Büttner C, Kube M. Complete genome determination and analysis of Acholeplasma oculi strain 19L, highlighting the loss of basic genetic features in the Acholeplasmataceae. BMC Genomics 2014; 15:931. [PMID: 25344468 PMCID: PMC4221730 DOI: 10.1186/1471-2164-15-931] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 09/25/2014] [Indexed: 11/17/2022] Open
Abstract
Background Acholeplasma oculi belongs to the Acholeplasmataceae family, comprising the genera Acholeplasma and ‘Candidatus Phytoplasma’. Acholeplasmas are ubiquitous saprophytic bacteria. Several isolates are derived from plants or animals, whereas phytoplasmas are characterised as intracellular parasitic pathogens of plant phloem and depend on insect vectors for their spread. The complete genome sequences for eight strains of this family have been resolved so far, all of which were determined depending on clone-based sequencing. Results The A. oculi strain 19L chromosome was sequenced using two independent approaches. The first approach comprised sequencing by synthesis (Illumina) in combination with Sanger sequencing, while single molecule real time sequencing (PacBio) was used in the second. The genome was determined to be 1,587,120 bp in size. Sequencing by synthesis resulted in six large genome fragments, while the single molecule real time sequencing approach yielded one circular chromosome sequence. High-quality sequences were obtained by both strategies differing in six positions, which are interpreted as reliable variations present in the culture population. Our genome analysis revealed 1,471 protein-coding genes and highlighted the absence of the F1FO-type Na+ ATPase system and GroEL/ES chaperone. Comparison of the four available Acholeplasma sequences revealed a core-genome encoding 703 proteins and a pan-genome of 2,867 proteins. Conclusions The application of two state-of-the-art sequencing technologies highlights the potential of single molecule real time sequencing for complete genome determination. Comparative genome analyses revealed that the process of losing particular basic genetic features during genome reduction occurs in both genera, as indicated for several phytoplasma strains and at least A. oculi. The loss of the F1FO-type Na+ ATPase system may separate Acholeplasmataceae from other Mollicutes, while the loss of those genes encoding the chaperone GroEL/ES is not a rare exception in this bacterial class. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-931) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | | | - Michael Kube
- Humboldt-Universität zu Berlin, Faculty of Life Science, Thaer-Institute, Division Phytomedicine, Lentzeallee 55/57, 14195 Berlin, Germany.
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Abstract
Methionine is essential in all organisms, as it is both a proteinogenic amino acid and a component of the cofactor, S-adenosyl methionine. The metabolic pathway for its biosynthesis has been extensively characterized in Escherichia coli; however, it is becoming apparent that most bacterial species do not use the E. coli pathway. Instead, studies on other organisms and genome sequencing data are uncovering significant diversity in the enzymes and metabolic intermediates that are used for methionine biosynthesis. This review summarizes the different biochemical strategies that are employed in the three key steps for methionine biosynthesis from homoserine (i.e. acylation, sulfurylation and methylation). A survey is presented of the presence and absence of the various biosynthetic enzymes in 1593 representative bacterial species, shedding light on the non-canonical nature of the E. coli pathway. This review also highlights ways in which knowledge of methionine biosynthesis can be utilized for biotechnological applications. Finally, gaps in the current understanding of bacterial methionine biosynthesis are noted. For example, the paper discusses the presence of one gene (metC) in a large number of species that appear to lack the gene encoding the enzyme for the preceding step in the pathway (metB), as it is understood in E. coli. Therefore, this review aims to move the focus away from E. coli, to better reflect the true diversity of bacterial pathways for methionine biosynthesis.
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Affiliation(s)
- Matteo P. Ferla
- Department of Biochemistry, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Wayne M. Patrick
- Department of Biochemistry, University of Otago, PO Box 56, Dunedin 9054, New Zealand
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Santos-Garcia D, Latorre A, Moya A, Gibbs G, Hartung V, Dettner K, Kuechler SM, Silva FJ. Small but powerful, the primary endosymbiont of moss bugs, Candidatus Evansia muelleri, holds a reduced genome with large biosynthetic capabilities. Genome Biol Evol 2014; 6:1875-93. [PMID: 25115011 PMCID: PMC4122945 DOI: 10.1093/gbe/evu149] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Moss bugs (Coleorrhyncha: Peloridiidae) are members of the order Hemiptera, and like many hemipterans, they have symbiotic associations with intracellular bacteria to fulfill nutritional requirements resulting from their unbalanced diet. The primary endosymbiont of the moss bugs, Candidatus Evansia muelleri, is phylogenetically related to Candidatus Carsonella ruddii and Candidatus Portiera aleyrodidarum, primary endosymbionts of psyllids and whiteflies, respectively. In this work, we report the genome of Candidatus Evansia muelleri Xc1 from Xenophyes cascus, which is the only obligate endosymbiont present in the association. This endosymbiont possesses an extremely reduced genome similar to Carsonella and Portiera. It has crossed the borderline to be considered as an autonomous cell, requiring the support of the insect host for some housekeeping cell functions. Interestingly, in spite of its small genome size, Evansia maintains enriched amino acid (complete or partial pathways for ten essential and six nonessential amino acids) and sulfur metabolisms, probably related to the poor diet of the insect, based on bryophytes, which contains very low levels of nitrogenous and sulfur compounds. Several facts, including the congruence of host (moss bugs, whiteflies, and psyllids) and endosymbiont phylogenies and the retention of the same ribosomal RNA operon during genome reduction in Evansia, Portiera, and Carsonella, suggest the existence of an ancient endosymbiotic Halomonadaceae clade associated with Hemiptera. Three possible scenarios for the origin of these three primary endosymbiont genera are proposed and discussed.
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Affiliation(s)
- Diego Santos-Garcia
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
| | - Amparo Latorre
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
- Unidad Mixta de Investigación en Genómica y Salud (FISABIO-Salud Pública and Universitat de València), Spain
| | - Andrés Moya
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
- Unidad Mixta de Investigación en Genómica y Salud (FISABIO-Salud Pública and Universitat de València), Spain
| | - George Gibbs
- School of Biological Science, Victoria University, Wellington, New Zealand
| | - Viktor Hartung
- Museum für Naturkunde, Leibniz-Institute for Research on Evolution and Biodiversity, Berlin, Germany
| | - Konrad Dettner
- Department of Animal Ecology II, University of Bayreuth, Germany
| | - Stefan Martin Kuechler
- Department of Animal Ecology II, University of Bayreuth, Germany
- *Corresponding author: E-mail: ;
| | - Francisco J. Silva
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
- Unidad Mixta de Investigación en Genómica y Salud (FISABIO-Salud Pública and Universitat de València), Spain
- *Corresponding author: E-mail: ;
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15
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Martínez-Cuesta MDC, Peláez C, Requena T. Methionine metabolism: major pathways and enzymes involved and strategies for control and diversification of volatile sulfur compounds in cheese. Crit Rev Food Sci Nutr 2013; 53:366-85. [PMID: 23320908 DOI: 10.1080/10408398.2010.536918] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
For economical reasons and to accommodate current market trends, cheese manufacturers and product developers are increasingly interested in controlling cheese flavor formation and developing new flavors. Due to their low detection threshold and diversity, volatile sulfur compounds (VSCs) are of prime importance in the overall flavor of cheese and make a significant contribution to their typical flavors. Thus, the control of VSCs formation offers considerable potential for industrial applications. This paper gives an overview of the main VSCs found in cheese, along with the major pathways and key enzymes leading to the formation of methanethiol from methionine, which is subsequently converted into other sulfur-bearing compounds. As these compounds arise primarily from methionine, the metabolism of this amino acid and its regulation is presented. Attention is focused in the enzymatic potential of lactic acid bacteria (LAB) that are widely used as starter and adjunct cultures in cheese-making. In view of industrial applications, different strategies such as the enhancement of the abilities of LAB to produce high amounts and diversity of VSCs are highlighted as the principal future research trend.
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Affiliation(s)
- María Del Carmen Martínez-Cuesta
- Department of Biotechnology and Microbiology, Instituto de Investigación en Ciencias de la Alimentación, CIAL (CSIC-UAM), Campus Universidad Autónoma, Madrid, Spain.
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16
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Metabolic adaptation of Ralstonia solanacearum during plant infection: a methionine biosynthesis case study. PLoS One 2012; 7:e36877. [PMID: 22615832 PMCID: PMC3353975 DOI: 10.1371/journal.pone.0036877] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 04/13/2012] [Indexed: 11/19/2022] Open
Abstract
MetE and MetH are two distinct enzymes that catalyze a similar biochemical reaction during the last step of methionine biosynthesis, MetH being a cobalamin-dependent enzyme whereas MetE activity is cobalamin-independent. In this work, we show that the last step of methionine synthesis in the plant pathogen Ralstonia solanacearum is under the transcriptional control of the master pathogenicity regulator HrpG. This control is exerted essentially on metE expression through the intermediate regulator MetR. Expression of metE is strongly and specifically induced in the presence of plant cells in a hrpG- and metR-dependent manner. metE and metR mutants are not auxotrophic for methionine and not affected for growth inside the plant but produce significantly reduced disease symptoms on tomato whereas disruption of metH has no impact on pathogenicity. The finding that the pathogen preferentially induces metE expression rather than metH in the presence of plant cells is indicative of a probable metabolic adaptation to physiological host conditions since this induction of metE occurs in an environment in which cobalamin, the required co-factor for MetH, is absent. It also shows that MetE and MetH are not functionally redundant and are deployed during specific stages of the bacteria lifecycle, the expression of metE and metH being controlled by multiple and distinct signals.
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17
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Molina-Henares MA, de la Torre J, García-Salamanca A, Molina-Henares AJ, Herrera MC, Ramos JL, Duque E. Identification of conditionally essential genes for growth ofPseudomonas putidaKT2440 on minimal medium through the screening of a genome-wide mutant library. Environ Microbiol 2010; 12:1468-85. [DOI: 10.1111/j.1462-2920.2010.02166.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Swarming of Pseudomonas aeruginosa is controlled by a broad spectrum of transcriptional regulators, including MetR. J Bacteriol 2009; 191:5592-602. [PMID: 19592586 DOI: 10.1128/jb.00157-09] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa exhibits swarming motility on semisolid surfaces (0.5 to 0.7% agar). Swarming is a more than just a form of locomotion and represents a complex adaptation resulting in changes in virulence gene expression and antibiotic resistance. In this study, we used a comprehensive P. aeruginosa PA14 transposon mutant library to investigate how the complex swarming adaptation process is regulated. A total of 233 P. aeruginosa PA14 transposon mutants were verified to have alterations in swarming motility. The swarming-associated genes functioned not only in flagellar or type IV pilus biosynthesis but also in processes as diverse as transport, secretion, and metabolism. Thirty-three swarming-deficient and two hyperswarming mutants had transposon insertions in transcriptional regulator genes, including genes encoding two-component sensors and response regulators; 27 of these insertions were newly identified. Of the 25 regulatory mutants whose swarming motility was highly impaired (79 to 97%), only 1 (a PA1458 mutant) had a major defect in swimming, suggesting that this regulator might influence flagellar synthesis or function. Twitching motility, which requires type IV pili, was strongly affected in only two regulatory mutants (pilH and PA2571 mutants) and was moderately affected in three other mutants (algR, ntrB, and nosR mutants). Microarray analyses were performed to compare the gene expression profile of a swarming-deficient PA3587 mutant to that of the wild-type PA14 strain under swarming conditions. PA3587 showed 63% homology to metR, which encodes a regulator of methionine biosynthesis in Escherichia coli. The observed dysregulation in the metR mutant of nine different genes required for swarming motility provided a possible explanation for the swarming-deficient phenotype of this mutant.
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19
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Development of stable isotope and selenomethionine labeling methods for proteins expressed in Pseudomonas fluorescens. Protein Expr Purif 2008; 65:57-65. [PMID: 19166940 DOI: 10.1016/j.pep.2008.12.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 12/16/2008] [Accepted: 12/22/2008] [Indexed: 11/22/2022]
Abstract
Pseudomonas fluorescens is a robust protein expression system that is very well suited for high throughput protein expression for structural genomics studies. Since NMR spectroscopy and X-ray crystallography are both used by various investigators in structure elucidation studies, the availability of target proteins labeled with stable isotopes or selenomethionine is essential for the determination of protein structures. A completely defined medium for the expression and stable isotope labeling of proteins in P. fluorescens has been developed. The expression level of Bacillus thuringiensis Cry34 in the modified medium is comparable to that obtained in the original medium. In addition, more than 95% incorporation of 15N was obtained in Cry34 using 15N ammonium sulfate and the quality of the protein, as assessed by NMR analysis, is comparable to that made using commercial medium. High levels of selenomethionine (SeMet) incorporation in the Xenorhabdus nematophilus insecticidal protein XptA2 were also obtained in P. fluorescens using the defined medium, allowing development of a method for obtaining highly purified XptA2. The following observations were made when inhibitors of endogenous methionine biosynthesis were used in P. fluorescens culture when SeMet was substituted in XptA2: (I) there is little inhibition of cell growth or recombinant XptA2 expression in the presence of SeMet concentrations up to 300 mg/L in cell culture, (II) there was greater than 95% SeMet incorporation ratio in recombinant SeMet-labeled XptA2 (SeMet-XptA2) and the incorporation ratio is consistent and reproducible and (III) finally, purified SeMet-XptA2 possesses similar protein structure and insecticidal activity relative to the unlabeled counterpart XptA2 as shown by bioassay and differential scanning calorimetric analysis. The high SeMet incorporation should provide high accuracy and resolution in XptA2 phase determination by multiwavelength anomalous diffraction (MAD), indicating that P. fluorescens is an excellent expression host to produce SeMet-labeled proteins for structural study.
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20
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de Berardinis V, Vallenet D, Castelli V, Besnard M, Pinet A, Cruaud C, Samair S, Lechaplais C, Gyapay G, Richez C, Durot M, Kreimeyer A, Le Fèvre F, Schächter V, Pezo V, Döring V, Scarpelli C, Médigue C, Cohen GN, Marlière P, Salanoubat M, Weissenbach J. A complete collection of single-gene deletion mutants of Acinetobacter baylyi ADP1. Mol Syst Biol 2008; 4:174. [PMID: 18319726 PMCID: PMC2290942 DOI: 10.1038/msb.2008.10] [Citation(s) in RCA: 236] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2007] [Accepted: 01/22/2008] [Indexed: 11/17/2022] Open
Abstract
We have constructed a collection of single-gene deletion mutants for all dispensable genes of the soil bacterium Acinetobacter baylyi ADP1. A total of 2594 deletion mutants were obtained, whereas 499 (16%) were not, and are therefore candidate essential genes for life on minimal medium. This essentiality data set is 88% consistent with the Escherichia coli data set inferred from the Keio mutant collection profiled for growth on minimal medium, while 80% of the orthologous genes described as essential in Pseudomonas aeruginosa are also essential in ADP1. Several strategies were undertaken to investigate ADP1 metabolism by (1) searching for discrepancies between our essentiality data and current metabolic knowledge, (2) comparing this essentiality data set to those from other organisms, (3) systematic phenotyping of the mutant collection on a variety of carbon sources (quinate, 2-3 butanediol, glucose, etc.). This collection provides a new resource for the study of gene function by forward and reverse genetic approaches and constitutes a robust experimental data source for systems biology approaches.
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21
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Heurlier K, Dénervaud V, Haas D. Impact of quorum sensing on fitness of Pseudomonas aeruginosa. Int J Med Microbiol 2006; 296:93-102. [PMID: 16503417 DOI: 10.1016/j.ijmm.2006.01.043] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
In Pseudomonas aeruginosa, cell-cell communication based on N-acyl-homoserine lactone (AHL) signal molecules (termed quorum sensing) is known to control the production of extracellular virulence factors. Hence, in pathogenic interactions with host organisms, the quorum-sensing (QS) machinery can confer a selective advantage on P. aeruginosa. However, as shown by transcriptomic and proteomic studies, many intracellular metabolic functions are also regulated by quorum sensing. Some of these serve to regenerate the AHL precursors methionine and S-adenosyl-methionine and to degrade adenosine via inosine and hypoxanthine. The fact that a significant percentage of clinical and environmental isolates of P. aeruginosa is defective for QS because of mutation in the major QS regulatory gene lasR, raises the question of whether the QS machinery can have a negative impact on the organism's fitness. In vitro, lasR mutants have a higher probability to escape lytic death in stationary phase under alkaline conditions than has the QS-proficient wild type. Similar selective forces might also operate in natural environments.
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Affiliation(s)
- Karin Heurlier
- Institute of Infection, Immunity, and Inflammation, Centre for Biomolecular Sciences, Nottingham University, Nottingham NG7 2RD, UK
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22
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Dos Santos VAPM, Heim S, Moore ERB, Strätz M, Timmis KN. Insights into the genomic basis of niche specificity of Pseudomonas putida KT2440. Environ Microbiol 2004; 6:1264-86. [PMID: 15560824 DOI: 10.1111/j.1462-2920.2004.00734.x] [Citation(s) in RCA: 217] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
A major challenge in microbiology is the elucidation of the genetic and ecophysiological basis of habitat specificity of microbes. Pseudomonas putida is a paradigm of a ubiquitous metabolically versatile soil bacterium. Strain KT2440, a safety strain that has become a laboratory workhorse worldwide, has been recently sequenced and its genome annotated. By drawing on both published information and on original in silico analysis of its genome, we address here the question of what genomic features of KT2440 could explain or are consistent with its ubiquity, metabolic versatility and adaptability. The genome of KT2440 exhibits combinations of features characteristic of terrestrial, rhizosphere and aquatic bacteria, which thrive in either copiotrophic or oligotrophic habitats, and suggests that P. putida has evolved and acquired functions that equip it to thrive in diverse, often inhospitable environments, either free-living, or in close association with plants. The high diversity of protein families encoded by its genome, the large number and variety of small aralogous families, insertion elements, repetitive extragenic palindromic sequences, as well as the mosaic structure of the genome (with many regions of 'atypical' composition) and the multiplicity of mobile elements, reflect a high functional diversity in P. putida and are indicative of its evolutionary trajectory and adaptation to the diverse habitats in which it thrives. The unusual wealth of determinants for high affinity nutrient acquisition systems, mono- and di-oxygenases, oxido-reductases, ferredoxins and cytochromes, dehydrogenases, sulfur metabolism proteins, for efflux pumps and glutathione-S-transfereases, and for the extensive array of extracytoplasmatic function sigma factors, regulators, and stress response systems, constitute the genomic basis for the exceptional nutritional versatility and opportunism of P. putida , its ubiquity in diverse soil, rhizosphere and aquatic systems, and its renowned tolerance of natural and anthropogenic stresses. This metabolic diversity is also the basis of the impressive evolutionary potential of KT2440, and its utility for the experimental design of novel pathways for the catabolism of organic, particularly aromatic, pollutants, and its potential for bioremediation of soils contaminated with such compounds as well as for its application in the production of high-added value compounds.
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Affiliation(s)
- V A P Martins Dos Santos
- Department of Environmental Microbiology, GBF - German Research Centre for Biotechnology, Braunschweig, Germany.
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23
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Rückert C, Pühler A, Kalinowski J. Genome-wide analysis of the L-methionine biosynthetic pathway in Corynebacterium glutamicum by targeted gene deletion and homologous complementation. J Biotechnol 2003; 104:213-28. [PMID: 12948640 DOI: 10.1016/s0168-1656(03)00158-5] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The genome sequence of Corynebacterium glutamicum, a gram-positive soil bacterium widely used as an amino acid producer, was analyzed by a similarity-based approach to elucidate the pathway for the biosynthesis of L-methionine. The functions of candidate ORFs were derived by gene deletion and, if necessary, by homologous complementation of suitable mutants. Of nine candidate ORFs (four of which were known previously), seven ORFs (cg0754 (metX), cg0755 (metY), cg1290 (metE), cg1702 (metH), cg2383 (metF), cg2536 (aecD), and cg2687 (metB)) were demonstrated to be part of the pathway while two others (cg0961 and cg3086) could be excluded. C. glutamicum synthesizes methionine in three, respectively four steps, starting from homoserine. C. glutamicum possesses two genes with similarity to homoserine acetyltransferases but only MetX can act as such while Cg0961 catalyzes a different, unknown reaction. For the incorporation of the sulfur moiety, the known functions of MetY and MetB could be confirmed and AecD was proven to be the only functional cystathionine beta-lyase in C. glutamicum, while Cg3086 can act neither as cystathionine gamma-synthase nor as cystathionine beta-lyase. Finally, MetE and MetH, which catalyze the conversion of L-homocysteine to L-methionine, could be newly identified, together with MetF which provides the necessary N(5)-methyltetrahydrofolate.
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Affiliation(s)
- C Rückert
- International Graduate School in Bioinformatics and Genome Research, Universität Bielefeld, Universitätsstr. 25, D-33594 Bielefeld, Germany
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Picardeau M, Bauby H, Saint Girons I. Genetic evidence for the existence of two pathways for the biosynthesis of methionine in the Leptospira spp. FEMS Microbiol Lett 2003; 225:257-62. [PMID: 12951250 DOI: 10.1016/s0378-1097(03)00529-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
There are two major pathways for methionine biosynthesis: the enterobacterial type transsulfuration pathway and the sulfhydrylation pathway as previously identified in the spirochete Leptospira meyeri. Sequence analysis of the L. meyeri metYX locus allows the identification of a third gene, called metW, which encodes a protein exhibiting similarities with homologs in many organisms belonging to the alpha-, beta-, and gamma-subdivisions of proteobacteria. The metW, metX and metY genes of L. meyeri were disrupted by a resistance cassette by homologous recombination. While the L. meyeri metX mutant shows methionine auxotrophy, the metY mutant (as well as the metW and metYmetW mutants) conserves methionine prototrophy, suggesting the presence of additional route(s) which may bypass the direct sulfhydrylation pathway. In addition, a L. interrogans gene, called metZ, was found to complement an Escherichia coli metB mutant, further suggesting that the transsulfuration pathway is also present in Leptospira spp.
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Affiliation(s)
- Mathieu Picardeau
- Unité de Bactériologie Moléculaire et Médicale, Institut Pasteur, 28 rue du docteur Roux, 75724 Paris Cedex 15, France.
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