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Wang J, Zou Z, Hu M, Shan X, Zhang Y, Miao Y, Zhang X, Islam N, Hu Q. Riemerella anatipestifer UvrC is required for iron utilization, biofilm formation and virulence. Avian Pathol 2024; 53:247-256. [PMID: 38420684 DOI: 10.1080/03079457.2024.2317431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 02/06/2024] [Indexed: 03/02/2024]
Abstract
UvrC is a subunit of excinuclease ABC, which mediates nucleotide excision repair (NER) in bacteria. Our previous studies showed that transposon Tn4531 insertion in the UvrC encoding gene Riean_1413 results in reduced biofilm formation by Riemerella anatipestifer strain CH3 and attenuates virulence of strain YZb1. In this study, whether R. anatipestifer UvrC has some biological functions other than NER was investigated. Firstly, the uvrC of R. anatipestifer strain Yb2 was in-frame deleted by homologous recombination, generating deletion mutant ΔuvrC, and its complemented strain cΔuvrC was constructed based on Escherichia coli - R. anatipestifer shuttle plasmid pRES. Compared to the wild-type (WT) R. anatipestifer strain Yb2, uvrC deleted mutant ΔuvrC significantly reduced biofilm formation, tolerance to H2O2- and HOCl-induced oxidative stress, iron utilization, and adhesion to and invasion of duck embryonic hepatocytes, but not its growth curve and proteolytic activity. In addition, animal experiments showed that the LD50 value of ΔuvrC in ducklings was about 13-fold higher than that of the WT, and the bacterial loads in ΔuvrC infected ducklings were significantly lower than those in Yb2-infected ducklings, indicating uvrC deletion in R. anatipestifer attenuated virulence. Taken together, the results of this study indicate that R. anatipestifer UvrC is required for iron utilization, biofilm formation, oxidative stress tolerance and virulence of strain Yb2, demonstrating multiple functions of UvrC.RESEARCH HIGHLIGHTSDeletion of uvrC in R. anatipestfer Yb2 significantly reduced its biofilm formation.uvrC deletion led to reduced tolerance to H2O2- and HOCl-induced oxidative stress.The iron utilization of uvrC deleted mutant was significantly reduced.The uvrC deletion in R. anatipestifer Yb2 attenuated its virulence.
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Affiliation(s)
- Jialing Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People's Republic of China
| | - Zuocheng Zou
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People's Republic of China
| | - Mengmeng Hu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People's Republic of China
| | - Xinggen Shan
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People's Republic of China
| | - Ying Zhang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People's Republic of China
| | - Yiqin Miao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People's Republic of China
| | - XiaoYing Zhang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People's Republic of China
| | - Nazrul Islam
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People's Republic of China
| | - Qinghai Hu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People's Republic of China
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2
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Skotnicová P, Srivastava A, Aggarwal D, Talbot J, Karlínová I, Moos M, Mareš J, Bučinská L, Koník P, Šimek P, Tichý M, Sobotka R. A thylakoid biogenesis BtpA protein is required for the initial step of tetrapyrrole biosynthesis in cyanobacteria. THE NEW PHYTOLOGIST 2024; 241:1236-1249. [PMID: 37986097 DOI: 10.1111/nph.19397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 10/21/2023] [Indexed: 11/22/2023]
Abstract
Biogenesis of the photosynthetic apparatus requires complicated molecular machinery, individual components of which are either poorly characterized or unknown. The BtpA protein has been described as a factor required for the stability of photosystem I (PSI) in cyanobacteria; however, how the BtpA stabilized PSI remains unexplained. To clarify the role of BtpA, we constructed and characterized the btpA-null mutant (ΔbtpA) in the cyanobacterium Synechocystis sp. PCC 6803. The mutant contained only c. 1% of chlorophyll and nearly no thylakoid membranes. However, this strain, growing only in the presence of glucose, was genetically unstable and readily generated suppressor mutations that restore the photoautotrophy. Two suppressor mutations were mapped into the hemA gene encoding glutamyl-tRNA reductase (GluTR) - the first enzyme of tetrapyrrole biosynthesis. Indeed, the GluTR was not detectable in the ΔbtpA mutant and the suppressor mutations restored biosynthesis of tetrapyrroles and photoautotrophy by increased GluTR expression or by improved GluTR stability/processivity. We further demonstrated that GluTR associates with a large BtpA oligomer and that BtpA is required for the stability of GluTR. Our results show that the BtpA protein is involved in the biogenesis of photosystems at the level of regulation of tetrapyrrole biosynthesis.
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Affiliation(s)
- Petra Skotnicová
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Třeboň, 379 01, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, 370 05, Czech Republic
| | - Amit Srivastava
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Třeboň, 379 01, Czech Republic
- Department of Biological and Environmental Science, Nanoscience Centre, University of Jyväskylä, Jyväskylä, 40014, Finland
| | - Divya Aggarwal
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Třeboň, 379 01, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, 370 05, Czech Republic
| | - Jana Talbot
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Třeboň, 379 01, Czech Republic
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, Tas., 7005, Australia
| | - Iva Karlínová
- Biology Centre of the Czech Academy of Sciences, České Budějovice, 370 05, Czech Republic
| | - Martin Moos
- Biology Centre of the Czech Academy of Sciences, České Budějovice, 370 05, Czech Republic
| | - Jan Mareš
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Třeboň, 379 01, Czech Republic
- Biology Centre of the Czech Academy of Sciences, České Budějovice, 370 05, Czech Republic
| | - Lenka Bučinská
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Třeboň, 379 01, Czech Republic
| | - Peter Koník
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Třeboň, 379 01, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, 370 05, Czech Republic
| | - Petr Šimek
- Biology Centre of the Czech Academy of Sciences, České Budějovice, 370 05, Czech Republic
| | - Martin Tichý
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Třeboň, 379 01, Czech Republic
| | - Roman Sobotka
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Třeboň, 379 01, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, 370 05, Czech Republic
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3
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Sun X, Xiao Y, Yong C, Sun H, Li S, Huang H, Jiang H. Interactions between the nitrogen-fixing cyanobacterium Trichodesmium and siderophore-producing cyanobacterium Synechococcus under iron limitation. ISME COMMUNICATIONS 2024; 4:ycae072. [PMID: 38873030 PMCID: PMC11171426 DOI: 10.1093/ismeco/ycae072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 04/07/2024] [Indexed: 06/15/2024]
Abstract
As diazotrophic cyanobacteria of tremendous biomass, Trichodesmium continuously provide a nitrogen source for carbon-fixing cyanobacteria and drive the generation of primary productivity in marine environments. However, ocean iron deficiencies limit growth and metabolism of Trichodesmium. Recent studies have shown the co-occurrence of Trichodesmium and siderophore-producing Synechococcus in iron-deficient oceans, but whether siderophores secreted by Synechococcus can be used by Trichodesmium to adapt to iron deficiency is not clear. We constructed a mutant Synechococcus strain unable to produce siderophores to explore this issue. Synechococcus filtrates with or without siderophores were added into a Trichodesmium microbial consortium consisting of Trichodesmium erythraeum IMS 101 as the dominant microbe with chronic iron deficiency. By analyzing the physiological phenotype, metagenome, and metatranscriptome, we investigated the interactions between the nitrogen-fixing cyanobacterium Tricodesmium and siderophore-producing cyanobacterium Synechococcus under conditions of iron deficiency. The results indicated that siderophores secreted by Synechococcus are likely to chelate with free iron in the culture medium of the Trichodesmium consortium, reducing the concentration of bioavailable iron and posing greater challenges to the absorption of iron by Trichodesmium. These findings revealed the characteristics of iron-competitive utilization between diazotrophic cyanobacteria and siderophore-producing cyanobacteria, as well as potential interactions, and provide a scientific basis for understanding the regulatory effects of nutrient limitation on marine primary productivity.
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Affiliation(s)
- Xumei Sun
- School of Marine Sciences, Ningbo University, 818 Fenghua Road, Ningbo, Zhejiang, 315211, People’s Republic of China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), 1 Jintang Road, Zhuhai, Guangdong, 519000, People’s Republic of China
| | - Yan Xiao
- School of Life Sciences, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei, 430079, People’s Republic of China
| | - Chengwen Yong
- School of Marine Sciences, Ningbo University, 818 Fenghua Road, Ningbo, Zhejiang, 315211, People’s Republic of China
| | - Hansheng Sun
- School of Marine Sciences, Ningbo University, 818 Fenghua Road, Ningbo, Zhejiang, 315211, People’s Republic of China
| | - Shuangqing Li
- School of Marine Sciences, Ningbo University, 818 Fenghua Road, Ningbo, Zhejiang, 315211, People’s Republic of China
| | - Hailong Huang
- School of Marine Sciences, Ningbo University, 818 Fenghua Road, Ningbo, Zhejiang, 315211, People’s Republic of China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), 1 Jintang Road, Zhuhai, Guangdong, 519000, People’s Republic of China
| | - Haibo Jiang
- School of Marine Sciences, Ningbo University, 818 Fenghua Road, Ningbo, Zhejiang, 315211, People’s Republic of China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), 1 Jintang Road, Zhuhai, Guangdong, 519000, People’s Republic of China
- School of Life Sciences, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei, 430079, People’s Republic of China
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4
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Singh B, Singh S, Mahato AK, Dikshit HK, Tripathi K, Bhatia S. Delineation of novel genomic loci and putative candidate genes associated with seed iron and zinc content in lentil (Lens culinaris Medik.). PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2023; 335:111787. [PMID: 37419329 DOI: 10.1016/j.plantsci.2023.111787] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 06/23/2023] [Accepted: 07/04/2023] [Indexed: 07/09/2023]
Abstract
The use of molecular breeding approaches for development of lentil genotypes biofortified with essential micro-nutrients such as iron and zinc, could serve as a promising solution to address the problem of global malnutrition. Thus, genome-wide association study (GWAS) strategy was adopted in this study to identify the genomic regions associated with seed iron and zinc content in lentil. A panel of 95 diverse lentil genotypes, grown across three different geographical locations and evaluated for seed iron and zinc content, exhibited a wide range of variation. Genotyping-by-sequencing (GBS) analysis of the panel identified 33,745 significant single nucleotide polymorphisms (SNPs) that were distributed across all the 7 lentil chromosomes. Association mapping revealed 23 SNPs associated with seed iron content that were distributed across all the chromosomes except chromosome 3. Similarly, 14 SNPs associated with seed zinc content were also identified that were distributed across chromosomes 1, 2, 4, 5 and 6. Further, 80 genes were identified in the proximity of iron associated markers and 36 genes were identified in the proximity of zinc associated markers. Functional annotation of these genes revealed their putative involvement in iron and zinc metabolism. For seed iron content, two highly significant SNPs were found to be located within two putative candidate genes namely iron-sulfur cluster assembly (ISCA) and flavin binding monooxygenase (FMO) respectively. For zinc content, a highly significant SNP was detected in a gene encoding UPF0678 fatty acid-binding protein. Expression analysis of these genes and their putative interacting partners suggests their involvement in iron and zinc metabolism in lentil. Overall, in this study we have identified markers, putative candidate genes and predicted putative interacting protein partners significantly associated with iron and zinc metabolism that could be utilized in future breeding studies of lentil for nutrient biofortification.
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Affiliation(s)
- Baljinder Singh
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, PO Box No. 10531, New Delhi 110067, India
| | - Sangeeta Singh
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, PO Box No. 10531, New Delhi 110067, India
| | - Ajay Kumar Mahato
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, PO Box No. 10531, New Delhi 110067, India
| | - Harsh Kumar Dikshit
- Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Kuldeep Tripathi
- Division of Germplasm Evaluation, ICAR-National Bureau of Plant Genetic Resources, New Delhi, India
| | - Sabhyata Bhatia
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, PO Box No. 10531, New Delhi 110067, India.
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5
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Williams SM, Chatterji D. Dps Functions as a Key Player in Bacterial Iron Homeostasis. ACS OMEGA 2023; 8:34299-34309. [PMID: 37779979 PMCID: PMC10536872 DOI: 10.1021/acsomega.3c03277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 08/24/2023] [Indexed: 10/03/2023]
Abstract
Iron plays a vital role in the maintenance of life, being central to various cellular processes, from respiration to gene regulation. It is essential for iron to be stored in a nontoxic and readily available form. DNA binding proteins under starvation (Dps) belong to the ferritin family of iron storage proteins and are adept at storing iron in their hollow protein shells. Existing solely in prokaryotes, these proteins have the additional functions of DNA binding and protection from oxidative stress. Iron storage proteins play a functional role in storage, release, and transfer of iron and therefore are central to the optimal functioning of iron homeostasis. Here we review the multifarious properties of Dps through relevant biochemical and structural studies with a focus on iron storage and ferroxidation. We also examine the role of Dps as a possible candidate as an iron donor to iron-sulfur (Fe-S) clusters, which are ubiquitous to many biological processes.
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Affiliation(s)
- Sunanda Margrett Williams
- Institute
of Structural and Molecular Biology, Birkbeck,
University of London, Malet Street, London WC1E
7HX, United Kingdom
| | - Dipankar Chatterji
- Molecular
Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
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6
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Hendrix J, Epperson LE, Tong EI, Chan YL, Hasan NA, Dawrs SN, Norton GJ, Virdi R, Crooks JL, Chan ED, Honda JR, Strong M. Complete genome assembly of Hawai'i environmental nontuberculous mycobacteria reveals unexpected co-isolation with methylobacteria. PLoS One 2023; 18:e0291072. [PMID: 37703253 PMCID: PMC10499228 DOI: 10.1371/journal.pone.0291072] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 08/22/2023] [Indexed: 09/15/2023] Open
Abstract
Nontuberculous mycobacteria (NTM) are ubiquitous environmental opportunistic pathogens that can cause chronic lung disease. Within the United States, Hawai'i has the highest incidence of NTM lung disease, though the precise reasons are yet to be fully elucidated. One possibility is the high prevalence of NTM in the Hawai'i environment acting as a potential reservoir for opportunistic NTM infections. Through our previous initiatives to collect and characterize NTM in Hawai'i, community scientists of Hawai'i have collected thousands of environmental samples for sequencing. Here, these community scientists were invited for the first time into a high school lab in O'ahu for a genomic sequencing workshop, where participants sequenced four of the collected isolate genomic samples using the Oxford Nanopore Technologies MinION sequencer. Participants generated high quality long read data that when combined with short read Illumina data yielded complete bacterial genomic assemblies suitable for in-depth analysis. The gene annotation analysis identified a suite of genes that might help NTM thrive in the Hawai'i environment. Further, we found evidence of co-occurring methylobacteria, revealed from the sequencing data, suggesting that in some cases methylobacteria and NTM may coexist in the same niche, challenging previously accepted paradigms. The sequencing efforts presented here generated novel insights regarding the potential survival strategies and microbial interactions of NTM in the geographic hot spot of Hawai'i. We highlight the contributions of community scientists and present an activity that can be reimplemented as a workshop or classroom activity by other research groups to engage their local communities.
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Affiliation(s)
- Jo Hendrix
- Center for Genes, Environment, and Health, National Jewish Health, Denver, CO, United States of America
- Computational Bioscience Program, University of Colorado, Anschutz Medical Campus, Aurora, CO, United States of America
| | - L. Elaine Epperson
- Center for Genes, Environment, and Health, National Jewish Health, Denver, CO, United States of America
| | - Eric I. Tong
- ‘Iolani School, Honolulu, Hawai’i, United States of America
| | - Yvonne L. Chan
- ‘Iolani School, Honolulu, Hawai’i, United States of America
| | - Nabeeh A. Hasan
- Center for Genes, Environment, and Health, National Jewish Health, Denver, CO, United States of America
| | - Stephanie N. Dawrs
- Center for Genes, Environment, and Health, National Jewish Health, Denver, CO, United States of America
| | - Grant J. Norton
- Center for Genes, Environment, and Health, National Jewish Health, Denver, CO, United States of America
| | - Ravleen Virdi
- Center for Genes, Environment, and Health, National Jewish Health, Denver, CO, United States of America
| | - James L. Crooks
- Division of Biostatistics and Bioinformatics, National Jewish Health, Denver, CO, United States of America
- Department of Epidemiology, Colorado School of Public Health, Aurora, CO, United States of America
| | - Edward D. Chan
- Department of Medicine and Academic Affairs, National Jewish Health, Denver, CO, United States of America
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
- Department of Medicine, Rocky Mountain Regional Veterans Affairs Medical Center, Aurora, CO, United States of America
| | - Jennifer R. Honda
- Department of Cellular and Molecular Biology, School of Medicine, University of Texas Health Science Center at Tyler, Tyler, TX, United States of America
| | - Michael Strong
- Center for Genes, Environment, and Health, National Jewish Health, Denver, CO, United States of America
- Computational Bioscience Program, University of Colorado, Anschutz Medical Campus, Aurora, CO, United States of America
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7
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Niemand Wolhuter N, Ngakane L, de Wet TJ, Warren RM, Williams MJ. The Mycobacterium smegmatis HesB Protein, MSMEG_4272, Is Required for In Vitro Growth and Iron Homeostasis. Microorganisms 2023; 11:1573. [PMID: 37375075 DOI: 10.3390/microorganisms11061573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/07/2023] [Accepted: 06/09/2023] [Indexed: 06/29/2023] Open
Abstract
A-type carrier (ATC) proteins are proposed to function in the biogenesis of Fe-S clusters, although their exact role remains controversial. The genome of Mycobacterium smegmatis encodes a single ATC protein, MSMEG_4272, which belongs to the HesB/YadR/YfhF family of proteins. Attempts to generate an MSMEG_4272 deletion mutant by two-step allelic exchange were unsuccessful, suggesting that the gene is essential for in vitro growth. CRISPRi-mediated transcriptional knock-down of MSMEG_4272 resulted in a growth defect under standard culture conditions, which was exacerbated in mineral-defined media. The knockdown strain displayed reduced intracellular iron levels under iron-replete conditions and increased susceptibility to clofazimine, 2,3-dimethoxy-1,4-naphthoquinone (DMNQ), and isoniazid, while the activity of the Fe-S containing enzymes, succinate dehydrogenase, and aconitase were not affected. This study suggests that MSMEG_4272 plays a role in the regulation of intracellular iron levels and is required for in vitro growth of M. smegmatis, particularly during exponential growth.
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Affiliation(s)
- Nandi Niemand Wolhuter
- NRF/DSI Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town 7505, South Africa
| | - Lerato Ngakane
- NRF/DSI Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town 7505, South Africa
| | - Timothy J de Wet
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, Department of Pathology, University of Cape Town, Cape Town 7925, South Africa
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town 7925, South Africa
| | - Robin M Warren
- NRF/DSI Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town 7505, South Africa
| | - Monique J Williams
- NRF/DSI Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town 7505, South Africa
- Department of Molecular and Cell Biology, University of Cape Town, Cape Town 7700, South Africa
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8
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Abdirad S, Wu Y, Ghorbanzadeh Z, Tazangi SE, Amirkhani A, Fitzhenry MJ, Kazemi M, Ghaffari MR, Koobaz P, Zeinalabedini M, Habibpourmehraban F, Masoomi-Aladizgeh F, Atwell BJ, Mirzaei M, Salekdeh GH, Haynes PA. Proteomic analysis of the meristematic root zone in contrasting genotypes reveals new insights in drought tolerance in rice. Proteomics 2022; 22:e2200100. [PMID: 35920597 DOI: 10.1002/pmic.202200100] [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: 03/11/2022] [Revised: 07/18/2022] [Accepted: 07/21/2022] [Indexed: 12/29/2022]
Abstract
Drought is responsible for major losses in rice production. Root tips contain meristematic and elongation zones that play major roles in determination of root traits and adaptive strategies to drought. In this study we analysed two contrasting genotypes of rice: IR64, a lowland, drought-susceptible, and shallow-rooting genotype; and Azucena, an upland, drought-tolerant, and deep-rooting genotype. Samples were collected of root tips of plants grown under control and water deficit stress conditions. Quantitative proteomics analysis resulted in the identification of 7294 proteins from the root tips of IR64 and 6307 proteins from Azucena. Data are available via ProteomeXchange with identifier PXD033343. Using a Partial Least Square Discriminant Analysis on 4170 differentially abundant proteins, 1138 statistically significant proteins across genotypes and conditions were detected. Twenty two enriched biological processes showing contrasting patterns between two genotypes in response to stress were detected through gene ontology enrichment analysis. This included identification of novel proteins involved in root elongation with specific expression patterns in Azucena, including four Expansins and seven Class III Peroxidases. We also detected an antioxidant network and a metallo-sulfur cluster assembly machinery in Azucena, with roles in reactive oxygen species and iron homeostasis, and positive effects on root cell cycle, growth and elongation.
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Affiliation(s)
- Somayeh Abdirad
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran
| | - Yunqi Wu
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, New South Wales, Australia
| | - Zahra Ghorbanzadeh
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran
| | - Sara Esmaeili Tazangi
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran
| | - Ardeshir Amirkhani
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, New South Wales, Australia
| | - Matthew J Fitzhenry
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, New South Wales, Australia
| | - Mehrbano Kazemi
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran
| | - Mohammad Reza Ghaffari
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran
| | - Parisa Koobaz
- Department of Molecular Physiology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran
| | - Mehrshad Zeinalabedini
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran
| | | | | | - Brian J Atwell
- School of Natural Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Mehdi Mirzaei
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, New South Wales, Australia.,School of Natural Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Ghasem Hosseini Salekdeh
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran.,School of Natural Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Paul A Haynes
- School of Natural Sciences, Macquarie University, North Ryde, New South Wales, Australia
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9
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Spectroscopic and functional characterization of the [2Fe-2S] scaffold protein Nfu from Synechocystis PCC6803. Biochimie 2022; 192:51-62. [PMID: 34582998 PMCID: PMC8724361 DOI: 10.1016/j.biochi.2021.09.013] [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: 06/02/2021] [Revised: 09/20/2021] [Accepted: 09/21/2021] [Indexed: 01/03/2023]
Abstract
Iron-sulfur clusters are ubiquitous cofactors required for various essential metabolic processes. Conservation of proteins required for their biosynthesis and trafficking allows for simple bacteria to be used as models to aid in exploring these complex pathways in higher organisms. Cyanobacteria are among the most investigated organisms for these processes, as they are unicellular and can survive under photoautotrophic and heterotrophic conditions. Herein, we report the potential role of Synechocystis PCC6803 NifU (now named SyNfu) as the principal scaffold protein required for iron-sulfur cluster biosynthesis in that organism. SyNfu is a well-folded protein with distinct secondary structural elements, as evidenced by circular dichroism and a well-dispersed pattern of 1H-15N HSQC NMR peaks, and readily reconstitutes as a [2Fe-2S] dimeric protein complex. Cluster exchange experiments show that glutathione can extract the cluster from holo-SyNfu, but the transfer is unidirectional. We also confirm the ability of SyNfu to transfer cluster to both human ferredoxin 1 and ferredoxin 2, while also demonstrating the capacity to deliver cluster to both monothiol glutaredoxin 3 and dithiol glutaredoxin 2. This evidence supports the hypothesis that SyNfu indeed serves as the main scaffold protein in Synechocystis, as it has been shown to be the only protein required for viability in the absence of photoautotrophic conditions. Similar to other NFU-type cluster donors and other scaffold and carrier proteins, such as ISCU, SyNfu is shown by DSC to be structurally less stable than regular protein donors, while retaining a relatively well-defined tertiary structure as represented by 1H-15N HSQC NMR experiments.
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10
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Jia A, Zheng Y, Chen H, Wang Q. Regulation and Functional Complexity of the Chlorophyll-Binding Protein IsiA. Front Microbiol 2021; 12:774107. [PMID: 34867913 PMCID: PMC8635728 DOI: 10.3389/fmicb.2021.774107] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 10/25/2021] [Indexed: 11/17/2022] Open
Abstract
As the oldest known lineage of oxygen-releasing photosynthetic organisms, cyanobacteria play the key roles in helping shaping the ecology of Earth. Iron is an ideal transition metal for redox reactions in biological systems. Cyanobacteria frequently encounter iron deficiency due to the environmental oxidation of ferrous ions to ferric ions, which are highly insoluble at physiological pH. A series of responses, including architectural changes to the photosynthetic membranes, allow cyanobacteria to withstand this condition and maintain photosynthesis. Iron-stress-induced protein A (IsiA) is homologous to the cyanobacterial chlorophyll (Chl)-binding protein, photosystem II core antenna protein CP43. IsiA is the major Chl-containing protein in iron-starved cyanobacteria, binding up to 50% of the Chl in these cells, and this Chl can be released from IsiA for the reconstruction of photosystems during the recovery from iron limitation. The pigment–protein complex (CPVI-4) encoded by isiA was identified and found to be expressed under iron-deficient conditions nearly 30years ago. However, its precise function is unknown, partially due to its complex regulation; isiA expression is induced by various types of stresses and abnormal physiological states besides iron deficiency. Furthermore, IsiA forms a range of complexes that perform different functions. In this article, we describe progress in understanding the regulation and functions of IsiA based on laboratory research using model cyanobacteria.
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Affiliation(s)
- Anqi Jia
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Yanli Zheng
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Hui Chen
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Qiang Wang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
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11
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Mantas MJQ, Nunn PB, Ke Z, Codd GA, Barker D. Genomic insights into the biosynthesis and physiology of the cyanobacterial neurotoxin 2,4-diaminobutanoic acid (2,4-DAB). PHYTOCHEMISTRY 2021; 192:112953. [PMID: 34598041 DOI: 10.1016/j.phytochem.2021.112953] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 09/09/2021] [Accepted: 09/11/2021] [Indexed: 06/13/2023]
Abstract
Cyanobacteria are an ancient clade of photosynthetic prokaryotes, whose worldwide occurrence, especially in water, presents health hazards to humans and animals due to the production of a range of toxins (cyanotoxins). These include the sometimes co-occurring, non-encoded diaminoacid neurotoxins 2,4-diaminobutanoic acid (2,4-DAB) and its structural analogue β-N-methylaminoalanine (BMAA). Knowledge of the biosynthetic pathway for 2,4-DAB, and its role in cyanobacteria, is lacking. The aspartate 4-phosphate pathway is a known route of 2,4-DAB biosynthesis in other bacteria and in some plant species. Another pathway to 2,4-DAB has been described in Lathyrus species. Here, we use bioinformatics analyses to investigate hypotheses concerning 2,4-DAB biosynthesis in cyanobacteria. We assessed the presence or absence of each enzyme in candidate biosynthesis routes, the aspartate 4-phosphate pathway and a pathway to 2,4-DAB derived from S-adenosyl-L-methionine (SAM), in 130 cyanobacterial genomes using sequence alignment, profile hidden Markov models, substrate specificity/active site identification and the reconstruction of gene phylogenies. In the aspartate 4-phosphate pathway, for the 18 species encoding diaminobutanoate-2-oxo-glutarate transaminase, the co-localisation of genes encoding the transaminase with the downstream decarboxylase or ectoine synthase - often within hybrid non-ribosomal peptide synthetase (NRPS)-polyketide synthases (PKS) clusters, NRPS-independent siderophore (NIS) clusters and incomplete ectoine clusters - is compatible with the hypothesis that some cyanobacteria use the aspartate 4-phosphate pathway for 2,4-DAB production. Through this route, in cyanobacteria, 2,4-DAB may be functionally associated with environmental iron-scavenging, via the production of siderophores of the schizokinen/synechobactin type and of some polyamines. In the pathway to 2,4-DAB derived from SAM, eight cyanobacterial species encode homologs of SAM-dependent 3-amino-3-carboxypropyl transferases. Other enzymes in this pathway have not yet been purified or sequenced. Ultimately, the biosynthesis of 2,4-DAB appears to be either restricted to some cyanobacterial species, or there may be multiple and additional routes, and roles, for the synthesis of this neurotoxin.
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Affiliation(s)
- Maria José Q Mantas
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Charlotte Auerbach Road, The King's Buildings, Edinburgh, EH9 3FL, United Kingdom.
| | - Peter B Nunn
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, United Kingdom.
| | - Ziying Ke
- School of Biological Sciences, Roger Land Building, The King's Buildings, Alexander Crum Brown Road, Edinburgh, EH9 3FF, United Kingdom; Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, United Kingdom.
| | - Geoffrey A Codd
- School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, United Kingdom; School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, United Kingdom.
| | - Daniel Barker
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Charlotte Auerbach Road, The King's Buildings, Edinburgh, EH9 3FL, United Kingdom.
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12
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Das M, Dewan A, Shee S, Singh A. The Multifaceted Bacterial Cysteine Desulfurases: From Metabolism to Pathogenesis. Antioxidants (Basel) 2021; 10:997. [PMID: 34201508 PMCID: PMC8300815 DOI: 10.3390/antiox10070997] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/01/2021] [Accepted: 05/06/2021] [Indexed: 12/02/2022] Open
Abstract
Living cells have developed a relay system to efficiently transfer sulfur (S) from cysteine to various thio-cofactors (iron-sulfur (Fe-S) clusters, thiamine, molybdopterin, lipoic acid, and biotin) and thiolated tRNA. The presence of such a transit route involves multiple protein components that allow the flux of S to be precisely regulated as a function of environmental cues to avoid the unnecessary accumulation of toxic concentrations of soluble sulfide (S2-). The first enzyme in this relay system is cysteine desulfurase (CSD). CSD catalyzes the release of sulfane S from L-cysteine by converting it to L-alanine by forming an enzyme-linked persulfide intermediate on its conserved cysteine residue. The persulfide S is then transferred to diverse acceptor proteins for its incorporation into the thio-cofactors. The thio-cofactor binding-proteins participate in essential and diverse cellular processes, including DNA repair, respiration, intermediary metabolism, gene regulation, and redox sensing. Additionally, CSD modulates pathogenesis, antibiotic susceptibility, metabolism, and survival of several pathogenic microbes within their hosts. In this review, we aim to comprehensively illustrate the impact of CSD on bacterial core metabolic processes and its requirement to combat redox stresses and antibiotics. Targeting CSD in human pathogens can be a potential therapy for better treatment outcomes.
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Affiliation(s)
| | | | | | - Amit Singh
- Centre for Infectious Disease Research, Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India; (M.D.); (A.D.); (S.S.)
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13
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Hunnestad AV, Vogel AIM, Armstrong E, Digernes MG, Ardelan MV, Hohmann-Marriott MF. From the Ocean to the Lab-Assessing Iron Limitation in Cyanobacteria: An Interface Paper. Microorganisms 2020; 8:E1889. [PMID: 33260337 PMCID: PMC7760322 DOI: 10.3390/microorganisms8121889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/25/2020] [Accepted: 11/26/2020] [Indexed: 12/22/2022] Open
Abstract
Iron is an essential, yet scarce, nutrient in marine environments. Phytoplankton, and especially cyanobacteria, have developed a wide range of mechanisms to acquire iron and maintain their iron-rich photosynthetic machinery. Iron limitation studies often utilize either oceanographic methods to understand large scale processes, or laboratory-based, molecular experiments to identify underlying molecular mechanisms on a cellular level. Here, we aim to highlight the benefits of both approaches to encourage interdisciplinary understanding of the effects of iron limitation on cyanobacteria with a focus on avoiding pitfalls in the initial phases of collaboration. In particular, we discuss the use of trace metal clean methods in combination with sterile techniques, and the challenges faced when a new collaboration is set up to combine interdisciplinary techniques. Methods necessary for producing reliable data, such as High Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS), Flow Injection Analysis Chemiluminescence (FIA-CL), and 77K fluorescence emission spectroscopy are discussed and evaluated and a technical manual, including the preparation of the artificial seawater medium Aquil, cleaning procedures, and a sampling scheme for an iron limitation experiment is included. This paper provides a reference point for researchers to implement different techniques into interdisciplinary iron studies that span cyanobacteria physiology, molecular biology, and biogeochemistry.
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Affiliation(s)
- Annie Vera Hunnestad
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway; (A.V.H.); (M.G.D.)
| | - Anne Ilse Maria Vogel
- PhotoSynLab, Department of Biotechnology and Food Science, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway; (A.I.M.V.); (M.F.H.-M.)
| | - Evelyn Armstrong
- NIWA/University of Otago Research Centre for Oceanography, Department of Chemistry, University of Otago, 9054 Dunedin, New Zealand;
| | - Maria Guadalupe Digernes
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway; (A.V.H.); (M.G.D.)
| | - Murat Van Ardelan
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway; (A.V.H.); (M.G.D.)
| | - Martin Frank Hohmann-Marriott
- PhotoSynLab, Department of Biotechnology and Food Science, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway; (A.I.M.V.); (M.F.H.-M.)
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14
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Kroh GE, Pilon M. Regulation of Iron Homeostasis and Use in Chloroplasts. Int J Mol Sci 2020; 21:E3395. [PMID: 32403383 PMCID: PMC7247011 DOI: 10.3390/ijms21093395] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/08/2020] [Accepted: 05/09/2020] [Indexed: 01/20/2023] Open
Abstract
Iron (Fe) is essential for life because of its role in protein cofactors. Photosynthesis, in particular photosynthetic electron transport, has a very high demand for Fe cofactors. Fe is commonly limiting in the environment, and therefore photosynthetic organisms must acclimate to Fe availability and avoid stress associated with Fe deficiency. In plants, adjustment of metabolism, of Fe utilization, and gene expression, is especially important in the chloroplasts during Fe limitation. In this review, we discuss Fe use, Fe transport, and mechanisms of acclimation to Fe limitation in photosynthetic lineages with a focus on the photosynthetic electron transport chain. We compare Fe homeostasis in Cyanobacteria, the evolutionary ancestors of chloroplasts, with Fe homeostasis in green algae and in land plants in order to provide a deeper understanding of how chloroplasts and photosynthesis may cope with Fe limitation.
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Affiliation(s)
| | - Marinus Pilon
- Department of Biology, Colorado State University Department of Biology, Fort Collins, CO 80523, USA;
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15
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Gao F. Iron-Sulfur Cluster Biogenesis and Iron Homeostasis in Cyanobacteria. Front Microbiol 2020; 11:165. [PMID: 32184761 PMCID: PMC7058544 DOI: 10.3389/fmicb.2020.00165] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Accepted: 01/23/2020] [Indexed: 01/23/2023] Open
Abstract
Iron–sulfur (Fe–S) clusters are ancient and ubiquitous cofactors and are involved in many important biological processes. Unlike the non-photosynthetic bacteria, cyanobacteria have developed the sulfur utilization factor (SUF) mechanism as their main assembly pathway for Fe–S clusters, supplemented by the iron–sulfur cluster and nitrogen-fixing mechanisms. The SUF system consists of cysteine desulfurase SufS, SufE that can enhance SufS activity, SufBC2D scaffold complex, carrier protein SufA, and regulatory repressor SufR. The S source for the Fe–S cluster assembly mainly originates from L-cysteine, but the Fe donor remains elusive. This minireview mainly focuses on the biogenesis pathway of the Fe–S clusters in cyanobacteria and its relationship with iron homeostasis. Future challenges of studying Fe–S clusters in cyanobacteria are also discussed.
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Affiliation(s)
- Fudan Gao
- College of Life Sciences, Shanghai Normal University, Shanghai, China
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16
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Wiltbank LB, Kehoe DM. Diverse light responses of cyanobacteria mediated by phytochrome superfamily photoreceptors. Nat Rev Microbiol 2020; 17:37-50. [PMID: 30410070 DOI: 10.1038/s41579-018-0110-4] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Cyanobacteria are an evolutionarily and ecologically important group of prokaryotes. They exist in diverse habitats, ranging from hot springs and deserts to glaciers and the open ocean. The range of environments that they inhabit can be attributed in part to their ability to sense and respond to changing environmental conditions. As photosynthetic organisms, one of the most crucial parameters for cyanobacteria to monitor is light. Cyanobacteria can sense various wavelengths of light and many possess a range of bilin-binding photoreceptors belonging to the phytochrome superfamily. Vital cellular processes including growth, phototaxis, cell aggregation and photosynthesis are tuned to environmental light conditions by these photoreceptors. In this Review, we examine the physiological responses that are controlled by members of this diverse family of photoreceptors and discuss the signal transduction pathways through which these photoreceptors operate. We highlight specific examples where the activities of multiple photoreceptors function together to fine-tune light responses. We also discuss the potential application of these photosensing systems in optogenetics and synthetic biology.
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Affiliation(s)
- Lisa B Wiltbank
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - David M Kehoe
- Department of Biology, Indiana University, Bloomington, IN, USA.
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17
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Garcia PS, Gribaldo S, Py B, Barras F. The SUF system: an ABC ATPase-dependent protein complex with a role in Fe-S cluster biogenesis. Res Microbiol 2019; 170:426-434. [PMID: 31419582 DOI: 10.1016/j.resmic.2019.08.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 07/30/2019] [Accepted: 08/07/2019] [Indexed: 12/13/2022]
Abstract
Iron-sulfur (Fe-S) clusters are considered one of the most ancient and versatile inorganic cofactors present in the three domains of life. Fe-S clusters can act as redox sensors or catalysts and are found to be used by a large number of functional and structurally diverse proteins. Here, we cover current knowledge of the SUF multiprotein machinery that synthesizes and inserts Fe-S clusters into proteins. Specific focus is put on the ABC ATPase SufC, which contributes to building Fe-S clusters, and appeared early on during evolution.
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Affiliation(s)
- Pierre Simon Garcia
- Department of Microbiology, Stress Adaptation and Metabolism in Enterobacteria Unit, ERL CNRS 6002, Institut Pasteur, 25-28 Rue du Dr Roux, 75015, Paris, France; Department of Microbiology, Evolutionary Biology of the Microbial Cell Unit, Institut Pasteur, 25-28 Rue du Dr Roux, 75015, Paris, France
| | - Simonetta Gribaldo
- Department of Microbiology, Evolutionary Biology of the Microbial Cell Unit, Institut Pasteur, 25-28 Rue du Dr Roux, 75015, Paris, France
| | - Béatrice Py
- Laboratoire de Chimie Bactérienne, UMR7243 Aix-Marseille Université CNRS, 31 Chemin Joseph Aiguier, 13009, Marseille, France.
| | - Frédéric Barras
- Department of Microbiology, Stress Adaptation and Metabolism in Enterobacteria Unit, ERL CNRS 6002, Institut Pasteur, 25-28 Rue du Dr Roux, 75015, Paris, France.
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18
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Bai Y, Chen T, Happe T, Lu Y, Sawyer A. Iron-sulphur cluster biogenesis via the SUF pathway. Metallomics 2019; 10:1038-1052. [PMID: 30019043 DOI: 10.1039/c8mt00150b] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Iron-sulphur (Fe-S) clusters are versatile cofactors, which are essential for key metabolic processes in cells, such as respiration and photosynthesis, and which may have also played a crucial role in establishing life on Earth. They can be found in almost all living organisms, from unicellular prokaryotes and archaea to multicellular animals and plants, and exist in diverse forms. This review focuses on the most ancient Fe-S cluster assembly system, the sulphur utilization factor (SUF) mechanism, which is crucial in bacteria for cell survival under stress conditions such as oxidation and iron starvation, and which is also present in the chloroplasts of green microalgae and plants, where it is responsible for plastidial Fe-S protein maturation. We explain the SUF Fe-S cluster assembly process, the proteins involved, their regulation and provide evolutionary insights. We specifically focus on examples from Fe-S cluster synthesis in the model organisms Escherichia coli and Arabidopsis thaliana and discuss in an in vivo context the assembly of the [FeFe]-hydrogenase H-cluster from Chlamydomonas reinhardtii.
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Affiliation(s)
- Y Bai
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
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19
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Blanco-Ameijeiras S, Cabanes DJE, Hassler CS. Towards the development of a new generation of whole-cell bioreporters to sense iron bioavailability in oceanic systems-learning from the case of Synechococcus sp. PCC7002 iron bioreporter. J Appl Microbiol 2019; 127:1291-1304. [PMID: 30970168 DOI: 10.1111/jam.14277] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 02/17/2019] [Accepted: 04/04/2019] [Indexed: 12/24/2022]
Abstract
Whole-cell bioreporters are genetically modified micro-organisms designed to sense bioavailable forms of nutrients or toxic compounds in aquatic systems. As they represent the most promising cost-efficient tools available for such purpose, engineering and use of bioreporters is rapidly growing in association with wide applicability. Bioreporters are urgently needed to determine phytoplankton iron (Fe) limitation, which has been reported in up to 30% of the ocean, with consequences affecting Earth's global carbon cycle and climate. This study presents a critical evaluation and optimization of the only Cyanobacteria bioreporter available to sense Fe limitation in marine systems (Synechococcus sp. PCC7002). The nonmonotonic biphasic dose-response curve between the bioreporters' signal and Fe bioavailability impairs an appropriate data interpretation, highlighting the need for new carefully designed bioreporters. Here, limitations under low Fe concentrations were related to cellular energy stress, nonlinear expression of the targeted promoter and siderophore expression. Furthermore, we provide critical standard criteria for the development of new Fe bioreporters. Finally, based on gene expression data under a range of marine Fe concentrations, we propose novel sensor genes for the development of new Cyanobacteria Fe bioreporters for distinct marine regions.
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Affiliation(s)
- S Blanco-Ameijeiras
- Department F.-A. Forel for Environmental and Aquatic Sciences, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - D J E Cabanes
- Department F.-A. Forel for Environmental and Aquatic Sciences, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - C S Hassler
- Department F.-A. Forel for Environmental and Aquatic Sciences, Faculty of Science, University of Geneva, Geneva, Switzerland
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20
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Carrier MC, Bourassa JS, Massé E. Cellular Homeostasis: A Small RNA at the Crossroads of Iron and Photosynthesis. Curr Biol 2019; 27:R380-R383. [PMID: 28535387 DOI: 10.1016/j.cub.2017.04.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The cyanobacterium Synechocystis relies on iron to perform oxygenic photosynthesis. This makes Synechocystis particularly sensitive to iron starvation. A new study shows that the small RNA IsaR1 is a major effector of the iron-stress response, remodeling the photosynthetic apparatus.
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Affiliation(s)
- Marie-Claude Carrier
- University of Sherbrooke, CRCHUS, Faculty of Medicine and Health Sciences, Department of Biochemistry, Sherbrooke, Quebec, Canada
| | - Jean-Sébastien Bourassa
- University of Sherbrooke, CRCHUS, Faculty of Medicine and Health Sciences, Department of Biochemistry, Sherbrooke, Quebec, Canada
| | - Eric Massé
- University of Sherbrooke, CRCHUS, Faculty of Medicine and Health Sciences, Department of Biochemistry, Sherbrooke, Quebec, Canada.
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21
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Årstøl E, Hohmann-Marriott MF. Cyanobacterial Siderophores-Physiology, Structure, Biosynthesis, and Applications. Mar Drugs 2019; 17:E281. [PMID: 31083354 PMCID: PMC6562677 DOI: 10.3390/md17050281] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/06/2019] [Accepted: 05/07/2019] [Indexed: 11/16/2022] Open
Abstract
Siderophores are low-molecular-weight metal chelators that function in microbial iron uptake. As iron limits primary productivity in many environments, siderophores are of great ecological importance. Additionally, their metal binding properties have attracted interest for uses in medicine and bioremediation. Here, we review the current state of knowledge concerning the siderophores produced by cyanobacteria. We give an overview of all cyanobacterial species with known siderophore production, finding siderophores produced in all but the most basal clades, and in a wide variety of environments. We explore what is known about the structure, biosynthesis, and cycling of the cyanobacterial siderophores that have been characterized: Synechobactin, schizokinen and anachelin. We also highlight alternative siderophore functionality and technological potential, finding allelopathic effects on competing phytoplankton and likely roles in limiting heavy-metal toxicity. Methodological improvements in siderophore characterization and detection are briefly described. Since most known cyanobacterial siderophores have not been structurally characterized, the application of mass spectrometry techniques will likely reveal a breadth of variation within these important molecules.
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Affiliation(s)
- Erland Årstøl
- Department of Biotechnology, PhotoSynLab, Norwegian University of Science and Technology, 7491 Trondheim, Norway.
| | - Martin F Hohmann-Marriott
- Department of Biotechnology, PhotoSynLab, Norwegian University of Science and Technology, 7491 Trondheim, Norway.
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22
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Touraine B, Vignols F, Przybyla-Toscano J, Ischebeck T, Dhalleine T, Wu HC, Magno C, Berger N, Couturier J, Dubos C, Feussner I, Caffarri S, Havaux M, Rouhier N, Gaymard F. Iron-sulfur protein NFU2 is required for branched-chain amino acid synthesis in Arabidopsis roots. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:1875-1889. [PMID: 30785184 DOI: 10.1093/jxb/erz050] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 01/25/2019] [Indexed: 05/23/2023]
Abstract
Numerous proteins require a metallic co-factor for their function. In plastids, the maturation of iron-sulfur (Fe-S) proteins necessitates a complex assembly machinery. In this study, we focused on Arabidopsis thaliana NFU1, NFU2, and NFU3, which participate in the final steps of the maturation process. According to the strong photosynthetic defects observed in high chlorophyll fluorescence 101 (hcf101), nfu2, and nfu3 plants, we determined that NFU2 and NFU3, but not NFU1, act immediately upstream of HCF101 for the maturation of [Fe4S4]-containing photosystem I subunits. An additional function of NFU2 in the maturation of the [Fe2S2] cluster of a dihydroxyacid dehydratase was obvious from the accumulation of precursors of the branched-chain amino acid synthesis pathway in roots of nfu2 plants and from the rescue of the primary root growth defect by supplying branched-chain amino acids. The absence of NFU3 in roots precluded any compensation. Overall, unlike their eukaryotic and prokaryotic counterparts, which are specific to [Fe4S4] proteins, NFU2 and NFU3 contribute to the maturation of both [Fe2S2] and [Fe4S4] proteins, either as a relay in conjunction with other proteins such as HCF101 or by directly delivering Fe-S clusters to client proteins. Considering the low number of Fe-S cluster transfer proteins relative to final acceptors, additional targets probably await identification.
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Affiliation(s)
- Brigitte Touraine
- BPMP, CNRS, INRA, Montpellier SupAgro, Université de Montpellier, Montpellier, France
| | - Florence Vignols
- BPMP, CNRS, INRA, Montpellier SupAgro, Université de Montpellier, Montpellier, France
| | | | - Till Ischebeck
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences and Göttingen Center for Molecular Biosciences (GZMB), University of Göttingen, 37077 Göttingen, Germany
| | | | - Hui-Chen Wu
- BPMP, CNRS, INRA, Montpellier SupAgro, Université de Montpellier, Montpellier, France
| | - Cyril Magno
- BPMP, CNRS, INRA, Montpellier SupAgro, Université de Montpellier, Montpellier, France
| | - Nathalie Berger
- BPMP, CNRS, INRA, Montpellier SupAgro, Université de Montpellier, Montpellier, France
| | | | - Christian Dubos
- BPMP, CNRS, INRA, Montpellier SupAgro, Université de Montpellier, Montpellier, France
| | - Ivo Feussner
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences and Göttingen Center for Molecular Biosciences (GZMB), University of Göttingen, 37077 Göttingen, Germany
| | - Stefano Caffarri
- Aix-Marseille Université, CEA Cadarache, CNRS UMR 7265, Laboratoire de Génétique et Biophysique des Plantes, 13009 Marseille, France
| | - Michel Havaux
- CEA Cadarache, CNRS UMR 7265, Aix-Marseille Université, Laboratoire d'Ecophysiologie Moléculaire des Plantes, 13108, Saint-Paul-lez-Durance, France
| | | | - Frédéric Gaymard
- BPMP, CNRS, INRA, Montpellier SupAgro, Université de Montpellier, Montpellier, France
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23
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Kreula SM, Kaewphan S, Ginter F, Jones PR. Finding novel relationships with integrated gene-gene association network analysis of Synechocystis sp. PCC 6803 using species-independent text-mining. PeerJ 2018; 6:e4806. [PMID: 29844966 PMCID: PMC5970561 DOI: 10.7717/peerj.4806] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 04/30/2018] [Indexed: 01/17/2023] Open
Abstract
The increasing move towards open access full-text scientific literature enhances our ability to utilize advanced text-mining methods to construct information-rich networks that no human will be able to grasp simply from ‘reading the literature’. The utility of text-mining for well-studied species is obvious though the utility for less studied species, or those with no prior track-record at all, is not clear. Here we present a concept for how advanced text-mining can be used to create information-rich networks even for less well studied species and apply it to generate an open-access gene-gene association network resource for Synechocystis sp. PCC 6803, a representative model organism for cyanobacteria and first case-study for the methodology. By merging the text-mining network with networks generated from species-specific experimental data, network integration was used to enhance the accuracy of predicting novel interactions that are biologically relevant. A rule-based algorithm (filter) was constructed in order to automate the search for novel candidate genes with a high degree of likely association to known target genes by (1) ignoring established relationships from the existing literature, as they are already ‘known’, and (2) demanding multiple independent evidences for every novel and potentially relevant relationship. Using selected case studies, we demonstrate the utility of the network resource and filter to (i) discover novel candidate associations between different genes or proteins in the network, and (ii) rapidly evaluate the potential role of any one particular gene or protein. The full network is provided as an open-source resource.
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Affiliation(s)
- Sanna M Kreula
- Department of Biochemistry, University of Turku, Turku, Finland.,University of Turku Graduate School, University of Turku, Turku, Finland
| | - Suwisa Kaewphan
- University of Turku Graduate School, University of Turku, Turku, Finland.,Turku Centre for Computer Science (TUCS), Turku, Finland.,Department of Future Technologies, University of Turku, Turku, Finland
| | - Filip Ginter
- Department of Future Technologies, University of Turku, Turku, Finland
| | - Patrik R Jones
- Department of Life Sciences, Imperial College London, London, United Kingdom
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24
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Pérez AA, Ferlez BH, Applegate AM, Walters K, He Z, Shen G, Golbeck JH, Bryant DA. Presence of a [3Fe-4S] cluster in a PsaC variant as a functional component of the photosystem I electron transfer chain in Synechococcus sp. PCC 7002. PHOTOSYNTHESIS RESEARCH 2018; 136:31-48. [PMID: 28916964 DOI: 10.1007/s11120-017-0437-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 08/23/2017] [Indexed: 06/07/2023]
Abstract
A site-directed C14G mutation was introduced into the stromal PsaC subunit of Synechococcus sp. strain PCC 7002 in vivo in order to introduce an exchangeable coordination site into the terminal FB [4Fe-4S] cluster of Photosystem I (PSI). Using an engineered PSI-less strain (psaAB deletion), psaC was deleted and replaced with recombinant versions controlled by a strong promoter, and the psaAB deletion was complemented. Modified PSI accumulated at lower levels in this strain and supported slower photoautotrophic growth than wild type. As-isolated PSI complexes containing PsaCC14G showed resonances with g values of 2.038 and 2.007 characteristic of a [3Fe-4S]1+ cluster. When the PSI complexes were illuminated at 15 K, these resonances partially disappeared and two new sets of resonances appeared. The majority set had g values of 2.05, 1.95, and 1.85, characteristic of FA-, and the minority set had g values of 2.11, 1.90, and 1.88 from FB' in the modified site. The S = 1/2 spin state of the latter implied the presence of a thiolate as the terminal ligand. The [3Fe-4S] clusters could be partially reconstituted with iron, producing a larger population of [4Fe-4S] clusters. Rates of flavodoxin reduction were identical in PSI complexes isolated from wild type and the PsaCC14G variant strain; this implied equivalent capacity for forward electron transfer in PSI complexes that contained [3Fe-4S] and [4Fe-4S] clusters. The development of this cyanobacterial strain is a first step toward translation of in vitro PSI-based biosolar molecular wire systems in vivo and provides new insights into the formation of Fe/S clusters.
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Affiliation(s)
- Adam A Pérez
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, 40202, USA
| | - Bryan H Ferlez
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, 28824, USA
| | - Amanda M Applegate
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
- Musculoskeletal Transplant Foundation, Jessup, PA, 18434, USA
| | - Karim Walters
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Zhihui He
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Gaozhong Shen
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA.
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA.
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA.
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA.
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25
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Benoit SL, Holland AA, Johnson MK, Maier RJ. Iron-sulfur protein maturation in Helicobacter pylori: identifying a Nfu-type cluster carrier protein and its iron-sulfur protein targets. Mol Microbiol 2018; 108:379-396. [PMID: 29498770 DOI: 10.1111/mmi.13942] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/23/2018] [Indexed: 01/03/2023]
Abstract
Helicobacter pylori is anomalous among non nitrogen-fixing bacteria in containing an incomplete NIF system for Fe-S cluster assembly comprising two essential proteins, NifS (cysteine desulfurase) and NifU (scaffold protein). Although nifU deletion strains cannot be obtained via the conventional gene replacement, a NifU-depleted strain was constructed and shown to be more sensitive to oxidative stress compared to wild-type (WT) strains. The hp1492 gene, encoding a putative Nfu-type Fe-S cluster carrier protein, was disrupted in three different H. pylori strains, indicating that it is not essential. However, Δnfu strains have growth deficiency, are more sensitive to oxidative stress and are unable to colonize mouse stomachs. Moreover, Δnfu strains have lower aconitase activity but higher hydrogenase activity than the WT. Recombinant Nfu was found to bind either one [2Fe-2S] or [4Fe-4S] cluster/dimer, based on analytical, UV-visible absorption/CD and resonance Raman studies. A bacterial two-hybrid system was used to ascertain interactions between Nfu, NifS, NifU and each of 36 putative Fe-S-containing target proteins. Nfu, NifS and NifU were found to interact with 15, 6 and 29 putative Fe-S proteins respectively. The results indicate that Nfu, NifS and NifU play a major role in the biosynthesis and/or delivery of Fe-S clusters in H. pylori.
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Affiliation(s)
- Stéphane L Benoit
- Department of Microbiology and Center for Metalloenzyme Studies, University of Georgia, Athens, GA 30602, USA
| | - Ashley A Holland
- Department of Chemistry and Center for Metalloenzyme Studies, University of Georgia, Athens, GA 30602, USA
| | - Michael K Johnson
- Department of Chemistry and Center for Metalloenzyme Studies, University of Georgia, Athens, GA 30602, USA
| | - Robert J Maier
- Department of Microbiology and Center for Metalloenzyme Studies, University of Georgia, Athens, GA 30602, USA
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26
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Fidai I, Wachnowsky C, Cowan JA. Mapping cellular Fe-S cluster uptake and exchange reactions - divergent pathways for iron-sulfur cluster delivery to human ferredoxins. Metallomics 2017; 8:1283-1293. [PMID: 27878189 DOI: 10.1039/c6mt00193a] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ferredoxins are protein mediators of biological electron-transfer reactions and typically contain either [2Fe-2S] or [4Fe-4S] clusters. Two ferredoxin homologues have been identified in the human genome, Fdx1 and Fdx2, that share 43% identity and 69% similarity in protein sequence and both bind [2Fe-2S] clusters. Despite the high similarity, the two ferredoxins play very specific roles in distinct physiological pathways and cannot replace each other in function. Both eukaryotic and prokaryotic ferredoxins and homologues have been reported to receive their Fe-S cluster from scaffold/delivery proteins such as IscU, Isa, glutaredoxins, and Nfu. However, the preferred and physiologically relevant pathway for receiving the [2Fe-2S] cluster by ferredoxins is subject to speculation and is not clearly identified. In this work, we report on in vitro UV-visible (UV-vis) circular dichroism studies of [2Fe-2S] cluster transfer to the ferredoxins from a variety of partners. The results reveal rapid and quantitative transfer to both ferredoxins from several donor proteins (IscU, Isa1, Grx2, and Grx3). Transfer from Isa1 to Fdx2 was also observed to be faster than that of IscU to Fdx2, suggesting that Fdx2 could receive its cluster from Isa1 instead of IscU. Several other transfer combinations were also investigated and the results suggest a complex, but kinetically detailed map for cellular cluster trafficking. This is the first step toward building a network map for all of the possible iron-sulfur cluster transfer pathways in the mitochondria and cytosol, providing insights on the most likely cellular pathways and possible redundancies in these pathways.
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Affiliation(s)
- Insiya Fidai
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, USA. and The Biophysics Graduate Program, The Ohio State University, USA
| | - Christine Wachnowsky
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, USA. and The Ohio State Biochemistry Program, The Ohio State University, USA
| | - J A Cowan
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, USA. and The Biophysics Graduate Program, The Ohio State University, USA and The Ohio State Biochemistry Program, The Ohio State University, USA
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27
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Zang SS, Jiang HB, Song WY, Chen M, Qiu BS. Characterization of the sulfur-formation (suf) genes in Synechocystis sp. PCC 6803 under photoautotrophic and heterotrophic growth conditions. PLANTA 2017; 246:927-938. [PMID: 28710587 DOI: 10.1007/s00425-017-2738-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 07/04/2017] [Indexed: 06/07/2023]
Abstract
The sulfur-formation ( suf ) genes play important roles in both photosynthesis and respiration of cyanobacteria, but the organism prioritizes Fe-S clusters for respiration at the expense of photosynthesis. Iron-sulfur (Fe-S) clusters are important to all living organisms, but their assembly mechanism is poorly understood in photosynthetic organisms. Unlike non-photosynthetic bacteria that rely on the iron-sulfur cluster system, Synechocystis sp. PCC 6803 uses the Sulfur-Formation (SUF) system as its major Fe-S cluster assembly pathway. The co-expression of suf genes and the direct interactions among SUF subunits indicate that Fe-S assembly is a complex process in which no suf genes can be knocked out completely. In this study, we developed a condition-controlled SUF Knockdown mutant by inserting the petE promoter, which is regulated by Cu2+ concentration, in front of the suf operon. Limited amount of the SUF system resulted in decreased chlorophyll contents and photosystem activities, and a lower PSI/PSII ratio. Unexpectedly, increased cyclic electron transport and a decreased dark respiration rate were only observed under photoautotrophic growth conditions. No visible effects on the phenotype of SUF Knockdown mutant were observed under heterotrophic culture conditions. The phylogenetic distribution of the SUF system indicates that it has a co-evolutionary relationship with photosynthetic energy storing pathways.
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Affiliation(s)
- Sha-Sha Zang
- School of Life Sciences, and Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, 430079, Hubei, People's Republic of China
| | - Hai-Bo Jiang
- School of Life Sciences, and Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, 430079, Hubei, People's Republic of China
| | - Wei-Yu Song
- School of Life Sciences, and Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, 430079, Hubei, People's Republic of China
| | - Min Chen
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, 2006, Australia
| | - Bao-Sheng Qiu
- School of Life Sciences, and Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, 430079, Hubei, People's Republic of China.
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28
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Georg J, Kostova G, Vuorijoki L, Schön V, Kadowaki T, Huokko T, Baumgartner D, Müller M, Klähn S, Allahverdiyeva Y, Hihara Y, Futschik ME, Aro EM, Hess WR. Acclimation of Oxygenic Photosynthesis to Iron Starvation Is Controlled by the sRNA IsaR1. Curr Biol 2017; 27:1425-1436.e7. [PMID: 28479323 DOI: 10.1016/j.cub.2017.04.010] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 04/06/2017] [Accepted: 04/10/2017] [Indexed: 01/01/2023]
Abstract
Oxygenic photosynthesis crucially depends on proteins that possess Fe2+ or Fe/S complexes as co-factors or prosthetic groups. Here, we show that the small regulatory RNA (sRNA) IsaR1 (Iron-Stress-Activated RNA 1) plays a pivotal role in acclimation to low-iron conditions. The IsaR1 regulon consists of more than 15 direct targets, including Fe2+-containing proteins involved in photosynthetic electron transfer, detoxification of anion radicals, citrate cycle, and tetrapyrrole biogenesis. IsaR1 is essential for maintaining physiological levels of Fe/S cluster biogenesis proteins during iron deprivation. Consequently, IsaR1 affects the acclimation of the photosynthetic apparatus to iron starvation at three levels: (1) directly, via posttranscriptional repression of gene expression; (2) indirectly, via suppression of pigment; and (3) Fe/S cluster biosynthesis. Homologs of IsaR1 are widely conserved throughout the cyanobacterial phylum. We conclude that IsaR1 is a critically important riboregulator. These findings provide a new perspective for understanding the regulation of iron homeostasis in photosynthetic organisms.
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Affiliation(s)
- Jens Georg
- Genetics & Experimental Bioinformatics, Institute of Biology III, Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Gergana Kostova
- Genetics & Experimental Bioinformatics, Institute of Biology III, Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Linda Vuorijoki
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014 Turku, Finland
| | - Verena Schön
- Genetics & Experimental Bioinformatics, Institute of Biology III, Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Taro Kadowaki
- Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Tuomas Huokko
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014 Turku, Finland
| | - Desirée Baumgartner
- Genetics & Experimental Bioinformatics, Institute of Biology III, Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Maximilian Müller
- Genetics & Experimental Bioinformatics, Institute of Biology III, Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Stephan Klähn
- Genetics & Experimental Bioinformatics, Institute of Biology III, Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Yagut Allahverdiyeva
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014 Turku, Finland
| | - Yukako Hihara
- Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Matthias E Futschik
- CCMAR - Center of Marine Sciences, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; School of Biomedical and Healthcare Sciences, Plymouth University, Plymouth, Devon PL4 8AA, UK
| | - Eva-Mari Aro
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014 Turku, Finland
| | - Wolfgang R Hess
- Genetics & Experimental Bioinformatics, Institute of Biology III, Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany.
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29
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Wachnowsky C, Fidai I, Cowan JA. Cytosolic iron-sulfur cluster transfer-a proposed kinetic pathway for reconstitution of glutaredoxin 3. FEBS Lett 2016; 590:4531-4540. [PMID: 27859051 DOI: 10.1002/1873-3468.12491] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 11/03/2016] [Accepted: 11/07/2016] [Indexed: 12/30/2022]
Abstract
Iron-sulfur (Fe-S) clusters are ubiquitously conserved and play essential cellular roles. The mechanism of Fe-S cluster biogenesis involves multiple proteins in a complex pathway. Cluster biosynthesis primarily occurs in the mitochondria, but key Fe-S proteins also exist in the cytosol. One such protein, glutaredoxin 3 (Grx3), is involved in iron regulation, sensing, and mediating [2Fe-2S] cluster delivery to cytosolic protein targets, but the cluster donor for cytosolic Grx3 has not been elucidated. Herein, we delineate the kinetic transfer of [2Fe-2S] clusters into Grx3 from potential cytosolic carrier/scaffold proteins, IscU and Nfu, to evaluate a possible model for Grx3 reconstitution in vivo.
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Affiliation(s)
- Christine Wachnowsky
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA.,The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, USA
| | - Insiya Fidai
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA.,The Biophysics Graduate Program, The Ohio State University, Columbus, OH, USA
| | - James A Cowan
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA.,The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, USA.,The Biophysics Graduate Program, The Ohio State University, Columbus, OH, USA
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30
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Sun J, Golbeck JH. The Presence of the IsiA-PSI Supercomplex Leads to Enhanced Photosystem I Electron Throughput in Iron-Starved Cells of Synechococcus sp. PCC 7002. J Phys Chem B 2015; 119:13549-59. [DOI: 10.1021/acs.jpcb.5b02176] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Junlei Sun
- Department of Biochemistry and Molecular Biology and ‡Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802 United States
| | - John H. Golbeck
- Department of Biochemistry and Molecular Biology and ‡Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802 United States
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31
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Mashruwala AA, Pang YY, Rosario-Cruz Z, Chahal HK, Benson MA, Anzaldi-Mike LL, Skaar EP, Torres VJ, Nauseef WM, Boyd JM. Nfu facilitates the maturation of iron-sulfur proteins and participates in virulence in Staphylococcus aureus. Mol Microbiol 2015; 95:383-409. [PMID: 25388433 PMCID: PMC4428306 DOI: 10.1111/mmi.12860] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/06/2014] [Indexed: 01/21/2023]
Abstract
The acquisition and metabolism of iron (Fe) by the human pathogen Staphylococcus aureus is critical for disease progression. S. aureus requires Fe to synthesize inorganic cofactors called iron-sulfur (Fe-S) clusters, which are required for functional Fe-S proteins. In this study we investigated the mechanisms utilized by S. aureus to metabolize Fe-S clusters. We identified that S. aureus utilizes the Suf biosynthetic system to synthesize Fe-S clusters and we provide genetic evidence suggesting that the sufU and sufB gene products are essential. Additional biochemical and genetic analyses identified Nfu as an Fe-S cluster carrier, which aids in the maturation of Fe-S proteins. We find that deletion of the nfu gene negatively impacts staphylococcal physiology and pathogenicity. A nfu mutant accumulates both increased intracellular non-incorporated Fe and endogenous reactive oxygen species (ROS) resulting in DNA damage. In addition, a strain lacking Nfu is sensitive to exogenously supplied ROS and reactive nitrogen species. Congruous with ex vivo findings, a nfu mutant strain is more susceptible to oxidative killing by human polymorphonuclear leukocytes and displays decreased tissue colonization in a murine model of infection. We conclude that Nfu is necessary for staphylococcal pathogenesis and establish Fe-S cluster metabolism as an attractive antimicrobial target.
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Affiliation(s)
- Ameya A. Mashruwala
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ 08901
| | - Yun Y. Pang
- Inflammation Program and Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, and Veterans Administration Medical Center, Iowa City, IA 52240
| | - Zuelay Rosario-Cruz
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ 08901
| | - Harsimranjit K. Chahal
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ 08901
| | - Meredith A. Benson
- Department of Microbiology, NYU Langone Medical Center, New York, NY 10016
| | - Laura L. Anzaldi-Mike
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Eric P. Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Victor J. Torres
- Department of Microbiology, NYU Langone Medical Center, New York, NY 10016
| | - William M. Nauseef
- Inflammation Program and Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, and Veterans Administration Medical Center, Iowa City, IA 52240
| | - Jeffrey M. Boyd
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ 08901
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32
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Giner-Lamia J, López-Maury L, Florencio FJ. Global transcriptional profiles of the copper responses in the cyanobacterium Synechocystis sp. PCC 6803. PLoS One 2014; 9:e108912. [PMID: 25268225 PMCID: PMC4182526 DOI: 10.1371/journal.pone.0108912] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 08/27/2014] [Indexed: 12/22/2022] Open
Abstract
Copper is an essential element involved in fundamental processes like respiration and photosynthesis. However, it becomes toxic at high concentration, which has forced organisms to control its cellular concentration. We have recently described a copper resistance system in the cyanobacterium Synechocystis sp. PCC 6803, which is mediated by the two-component system, CopRS, a RND metal transport system, CopBAC and a protein of unknown function, CopM. Here, we report the transcriptional responses to copper additions at non-toxic (0.3 µM) and toxic concentrations (3 µM) in the wild type and in the copper sensitive copR mutant strain. While 0.3 µM copper slightly stimulated metabolism and promoted the exchange between cytochrome c6 and plastocyanin as soluble electron carriers, the addition of 3 µM copper catalyzed the formation of ROS, led to a general stress response and induced expression of Fe-S cluster biogenesis genes. According to this, a double mutant strain copRsufR, which expresses constitutively the sufBCDS operon, tolerated higher copper concentration than the copR mutant strain, suggesting that Fe-S clusters are direct targets of copper toxicity in Synechocystis. In addition we have also demonstrated that InrS, a nickel binding transcriptional repressor that belong to the CsoR family of transcriptional factor, was involved in heavy metal homeostasis, including copper, in Synechocystis. Finally, global gene expression analysis of the copR mutant strain suggested that CopRS only controls the expression of copMRS and copBAC operons in response to copper.
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Affiliation(s)
- Joaquin Giner-Lamia
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Sevilla, Spain
| | - Luis López-Maury
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Sevilla, Spain
- * E-mail: (LLM); (FJF)
| | - Francisco J. Florencio
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Sevilla, Spain
- * E-mail: (LLM); (FJF)
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33
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Szekeres E, Sicora C, Dragoş N, Drugă B. Selection of proper reference genes for the cyanobacterium Synechococcus PCC 7002 using real-time quantitative PCR. FEMS Microbiol Lett 2014; 359:102-9. [PMID: 25115691 DOI: 10.1111/1574-6968.12574] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 08/07/2014] [Accepted: 08/07/2014] [Indexed: 11/30/2022] Open
Abstract
Synechococcus sp. PCC 7002 is known to be tolerant to most of the environmental factors in natural habitats of Cyanobacteria. Gene expression can be easily studied in this cyanobacterium, as its complete genome sequence is available. These properties make Synechococcus sp. PCC 7002 an appropriate model organism for biotechnological applications. To study the gene expression in Cyanobacteria, real-time quantitative PCR (qPCR) can be used, but as this is a highly sensitive method, data standardization is indicated between samples. The most commonly used strategy is normalization against internal reference genes. Synechococcus sp. PCC 7002 has not yet been evaluated for the best reference genes. In this work, six candidate genes were analyzed for this purpose. Cyanobacterial cultures were exposed to several stress conditions, and three different algorithms were used for ranking the reference genes: geNorm, NormFinder, and BestKeeper. Moreover, gene expression stability value M and single-control normalization error E were calculated. Our data provided a list of reference genes that can be used in qPCR experiments in Synechococcus sp. PCC 7002.
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34
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Evidence that histidine forms a coordination bond to the A0A and A0B chlorophylls and a second H-bond to the A1A and A1B phylloquinones in M688HPsaA and M668HPsaB variants of Synechocystis sp. PCC 6803. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:1362-75. [DOI: 10.1016/j.bbabio.2014.04.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 04/02/2014] [Accepted: 04/04/2014] [Indexed: 11/21/2022]
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35
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Liu D, Wang L, Liu C, Song X, He S, Zhai H, Liu Q. An Ipomoea batatas iron-sulfur cluster scaffold protein gene, IbNFU1, is involved in salt tolerance. PLoS One 2014; 9:e93935. [PMID: 24695556 PMCID: PMC3973627 DOI: 10.1371/journal.pone.0093935] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 03/08/2014] [Indexed: 12/18/2022] Open
Abstract
Iron-sulfur cluster biosynthesis involving the nitrogen fixation (Nif) proteins has been proposed as a general mechanism acting in various organisms. NifU-like protein may play an important role in protecting plants against abiotic and biotic stresses. An iron-sulfur cluster scaffold protein gene, IbNFU1, was isolated from a salt-tolerant sweetpotato (Ipomoea batatas (L.) Lam.) line LM79 in our previous study, but its role in sweetpotato stress tolerance was not investigated. In the present study, the IbNFU1 gene was introduced into a salt-sensitive sweetpotato cv. Lizixiang to characterize its function in salt tolerance. The IbNFU1-overexpressing sweetpotato plants exhibited significantly higher salt tolerance compared with the wild-type. Proline and reduced ascorbate content were significantly increased, whereas malonaldehyde (MDA) content was significantly decreased in the transgenic plants. The activities of superoxide dismutase (SOD) and photosynthesis were significantly enhanced in the transgenic plants. H2O2 was also found to be significantly less accumulated in the transgenic plants than in the wild-type. Overexpression of IbNFU1 up-regulated pyrroline-5-carboxylate synthase (P5CS) and pyrroline-5-carboxylate reductase (P5CR) genes under salt stress. The systemic up-regulation of reactive oxygen species (ROS) scavenging genes was found in the transgenic plants under salt stress. These findings suggest that IbNFU1gene is involved in sweetpotato salt tolerance and enhances salt tolerance of the transgenic sweetpotato plants by regulating osmotic balance, protecting membrane integrity and photosynthesis and activating ROS scavenging system.
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Affiliation(s)
- Degao Liu
- Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization, Ministry of Education, China Agricultural University, Beijing, China
| | - Lianjun Wang
- Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization, Ministry of Education, China Agricultural University, Beijing, China
- Institute of Food Crops, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Chenglong Liu
- Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization, Ministry of Education, China Agricultural University, Beijing, China
| | - Xuejin Song
- Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization, Ministry of Education, China Agricultural University, Beijing, China
| | - Shaozhen He
- Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization, Ministry of Education, China Agricultural University, Beijing, China
| | - Hong Zhai
- Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization, Ministry of Education, China Agricultural University, Beijing, China
| | - Qingchang Liu
- Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization, Ministry of Education, China Agricultural University, Beijing, China
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Reprint of: Iron/sulfur proteins biogenesis in prokaryotes: formation, regulation and diversity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:923-37. [PMID: 23660107 DOI: 10.1016/j.bbabio.2013.05.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 12/21/2012] [Accepted: 12/27/2012] [Indexed: 12/15/2022]
Abstract
Iron/sulfur centers are key cofactors of proteins intervening in multiple conserved cellular processes, such as gene expression, DNA repair, RNA modification, central metabolism and respiration. Mechanisms allowing Fe/S centers to be assembled, and inserted into polypeptides have attracted much attention in the last decade, both in eukaryotes and prokaryotes. Basic principles and recent advances in our understanding of the prokaryotic Fe/S biogenesis ISC and SUF systems are reviewed in the present communication. Most studies covered stem from investigations in Escherichia coli and Azotobacter vinelandii. Remarkable insights were brought about by complementary structural, spectroscopic, biochemical and genetic studies. Highlights of the recent years include scaffold mediated assembly of Fe/S cluster, A-type carriers mediated delivery of clusters and regulatory control of Fe/S homeostasis via a set of interconnected genetic regulatory circuits. Also, the importance of Fe/S biosynthesis systems in mediating soft metal toxicity was documented. A brief account of the Fe/S biosynthesis systems diversity as present in current databases is given here. Moreover, Fe/S biosynthesis factors have themselves been the object of molecular tailoring during evolution and some examples are discussed here. An effort was made to provide, based on the E. coli system, a general classification associating a given domain with a given function such as to help next search and annotation of genomes. This article is part of a Special Issue entitled: Metals in Bioenergetics and Biomimetics Systems.
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Roche B, Aussel L, Ezraty B, Mandin P, Py B, Barras F. Iron/sulfur proteins biogenesis in prokaryotes: formation, regulation and diversity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:455-69. [PMID: 23298813 DOI: 10.1016/j.bbabio.2012.12.010] [Citation(s) in RCA: 212] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 12/21/2012] [Accepted: 12/27/2012] [Indexed: 12/17/2022]
Abstract
Iron/sulfur centers are key cofactors of proteins intervening in multiple conserved cellular processes, such as gene expression, DNA repair, RNA modification, central metabolism and respiration. Mechanisms allowing Fe/S centers to be assembled, and inserted into polypeptides have attracted much attention in the last decade, both in eukaryotes and prokaryotes. Basic principles and recent advances in our understanding of the prokaryotic Fe/S biogenesis ISC and SUF systems are reviewed in the present communication. Most studies covered stem from investigations in Escherichia coli and Azotobacter vinelandii. Remarkable insights were brought about by complementary structural, spectroscopic, biochemical and genetic studies. Highlights of the recent years include scaffold mediated assembly of Fe/S cluster, A-type carriers mediated delivery of clusters and regulatory control of Fe/S homeostasis via a set of interconnected genetic regulatory circuits. Also, the importance of Fe/S biosynthesis systems in mediating soft metal toxicity was documented. A brief account of the Fe/S biosynthesis systems diversity as present in current databases is given here. Moreover, Fe/S biosynthesis factors have themselves been the object of molecular tailoring during evolution and some examples are discussed here. An effort was made to provide, based on the E. coli system, a general classification associating a given domain with a given function such as to help next search and annotation of genomes. This article is part of a Special Issue entitled: Metals in Bioenergetics and Biomimetics Systems.
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Affiliation(s)
- Béatrice Roche
- Institut de Microbiologie de la Méditerranée, Marseille, France
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Couturier J, Touraine B, Briat JF, Gaymard F, Rouhier N. The iron-sulfur cluster assembly machineries in plants: current knowledge and open questions. FRONTIERS IN PLANT SCIENCE 2013; 4:259. [PMID: 23898337 PMCID: PMC3721309 DOI: 10.3389/fpls.2013.00259] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 06/25/2013] [Indexed: 05/18/2023]
Abstract
Many metabolic pathways and cellular processes occurring in most sub-cellular compartments depend on the functioning of iron-sulfur (Fe-S) proteins, whose cofactors are assembled through dedicated protein machineries. Recent advances have been made in the knowledge of the functions of individual components through a combination of genetic, biochemical and structural approaches, primarily in prokaryotes and non-plant eukaryotes. Whereas most of the components of these machineries are conserved between kingdoms, their complexity is likely increased in plants owing to the presence of additional assembly proteins and to the existence of expanded families for several assembly proteins. This review focuses on the new actors discovered in the past few years, such as glutaredoxin, BOLA and NEET proteins as well as MIP18, MMS19, TAH18, DRE2 for the cytosolic machinery, which are integrated into a model for the plant Fe-S cluster biogenesis systems. It also discusses a few issues currently subjected to an intense debate such as the role of the mitochondrial frataxin and of glutaredoxins, the functional separation between scaffold, carrier and iron-delivery proteins and the crosstalk existing between different organelles.
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Affiliation(s)
- Jérémy Couturier
- Interactions Arbres/Micro-organismes, Faculté des Sciences, UMR1136 Université de Lorraine-INRAVandoeuvre, France
| | - Brigitte Touraine
- Biochimie et Physiologie Moléculaire des Plantes, Centre National de la Recherche Scientifique-INRA-Université Montpellier 2Montpellier, France
| | - Jean-François Briat
- Biochimie et Physiologie Moléculaire des Plantes, Centre National de la Recherche Scientifique-INRA-Université Montpellier 2Montpellier, France
| | - Frédéric Gaymard
- Biochimie et Physiologie Moléculaire des Plantes, Centre National de la Recherche Scientifique-INRA-Université Montpellier 2Montpellier, France
| | - Nicolas Rouhier
- Interactions Arbres/Micro-organismes, Faculté des Sciences, UMR1136 Université de Lorraine-INRAVandoeuvre, France
- *Correspondence: Nicolas Rouhier, Université de Lorraine, UMR1136 Université de Lorraine-INRA, Interactions Arbres/Micro-organismes, Faculté des Sciences, Bd des aiguillettes, BP 239,54506 Vandoeuvre, France e-mail:
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Mapolelo DT, Zhang B, Naik SG, Huynh BH, Johnson MK. Spectroscopic and functional characterization of iron-bound forms of Azotobacter vinelandii (Nif)IscA. Biochemistry 2012; 51:8056-70. [PMID: 23003563 DOI: 10.1021/bi300664j] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ability of Azotobacter vinelandii(Nif)IscA to bind Fe has been investigated to assess the role of Fe-bound forms in NIF-specific Fe-S cluster biogenesis. (Nif)IscA is shown to bind one Fe(III) or one Fe(II) per homodimer and the spectroscopic and redox properties of both the Fe(III)- and Fe(II)-bound forms have been characterized using the UV-visible absorption, circular dichroism, and variable-temperature magnetic circular dichroism, electron paramagnetic resonance, Mössbauer and resonance Raman spectroscopies. The results reveal a rhombic intermediate-spin (S = 3/2) Fe(III) center (E/D = 0.33, D = 3.5 ± 1.5 cm(-1)) that is most likely 5-coordinate with two or three cysteinate ligands and a rhombic high spin (S = 2) Fe(II) center (E/D = 0.28, D = 7.6 cm(-1)) with properties similar to reduced rubredoxins or rubredoxin variants with three cysteinate and one or two oxygenic ligands. Iron-bound (Nif)IscA undergoes reversible redox cycling between the Fe(III)/Fe(II) forms with a midpoint potential of +36 ± 15 mV at pH 7.8 (versus NHE). l-Cysteine is effective in mediating release of free Fe(II) from both the Fe(II)- and Fe(III)-bound forms of (Nif)IscA. Fe(III)-bound (Nif)IscA was also shown to be a competent iron source for in vitro NifS-mediated [2Fe-2S] cluster assembly on the N-terminal domain of NifU, but the reaction occurs via cysteine-mediated release of free Fe(II) rather than direct iron transfer. The proposed roles of A-type proteins in storing Fe under aerobic growth conditions and serving as iron donors for cluster assembly on U-type scaffold proteins or maturation of biological [4Fe-4S] centers are discussed in light of these results.
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Affiliation(s)
- Daphne T Mapolelo
- Department of Chemistry and Center for Metalloenzyme Studies, University of Georgia, Athens, GA 30602, USA
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Py B, Gerez C, Angelini S, Planel R, Vinella D, Loiseau L, Talla E, Brochier-Armanet C, Garcia Serres R, Latour JM, Ollagnier-de Choudens S, Fontecave M, Barras F. Molecular organization, biochemical function, cellular role and evolution of NfuA, an atypical Fe-S carrier. Mol Microbiol 2012; 86:155-71. [PMID: 22966982 DOI: 10.1111/j.1365-2958.2012.08181.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Biosynthesis of iron-sulphur (Fe-S) proteins is catalysed by multi-protein systems, ISC and SUF. However, 'non-ISC, non-SUF' Fe-S biosynthesis factors have been described, both in prokaryotes and eukaryotes. Here we report in vitro and in vivo investigations of such a 'non-ISC, non SUF' component, the Nfu proteins. Phylogenomic analysis allowed us to define four subfamilies. Escherichia coli NfuA is within subfamily II. Most members of this subfamily have a Nfu domain fused to a 'degenerate' A-type carrier domain (ATC*) lacking Fe-S cluster co-ordinating Cys ligands. The Nfu domain binds a [4Fe-4S] cluster while the ATC* domain interacts with NuoG (a complex I subunit) and aconitase B (AcnB). In vitro, holo-NfuA promotes maturation of AcnB. In vivo, NfuA is necessary for full activity of complex I under aerobic growth conditions, and of AcnB in the presence of superoxide. NfuA receives Fe-S clusters from IscU/HscBA and SufBCD scaffolds and eventually transfers them to the ATCs IscA and SufA. This study provides significant information on one of the Fe-S biogenesis factors that has been often used as a building block by ISC and/or SUF synthesizing organisms, including bacteria, plants and animals.
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Affiliation(s)
- Béatrice Py
- Laboratoire de Chimie Bactérienne, UMR 7283 Aix-Marseille Université-CNRS, Institut de Microbiologie de la Méditerranée, 31 Chemin Joseph Aiguier, 13009 Marseille, France
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Zhuang W, Yuan D, Li JR, Luo Z, Zhou HC, Bashir S, Liu J. Highly potent bactericidal activity of porous metal-organic frameworks. Adv Healthc Mater 2012. [PMID: 23184726 DOI: 10.1002/adhm.201100043] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Recent outbreaks of bacterial infection leading to human fatalities have been a motivational force for us to develop antibacterial agents with high potency and long-term stability. A novel cobalt (Co) based metal-organic framework (MOF) was tested and shown to be highly effective at inactivating model microorganisms. Gram-negative bacteria, Escherichia coli (strains DH5alpha and XL1-Blue) were selected to determine the antibacterial activities of the Co MOF. In this MOF, the Co serves as a central element and an octa-topic carboxylate ligand, tetrakis [(3,5-dicarboxyphenyl)-oxamethyl] methane (TDM(8-) ) serves as a bridging linker. X-ray crystallographic studies indicate that Co-TDM crystallizes in tetragonal space group P$\overline 4$2(1) m with a porous 3D framework. The potency of the Co-TDM disinfectant was evaluated using a minimal bactericidal concentration (MBC) benchmark and was determined to be 10-15 ppm within a short incubation time period (<60 min). Compared with previous work using silver nanoparticles and silver-modified TiO(2) nano- composites over the same time period, the MBC and effectiveness of Co-TDM are superior. Electron microscopy images indicate that the Co-TDM displayed distinctive grain boundaries and well-developed reticulates. The Co active sites rapidly catalyzed the lipid peroxidation, causing rupture of the bacterial membrane followed by inactivation, with 100% recycling and high persistence (>4 weeks). This MOF-based approach may lead to a new paradigm for MOF applications in diverse biological fields due to their inherent porous structure, tunable surface functional groups, and adjustable metal coordination environments.
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Affiliation(s)
- Wenjuan Zhuang
- Chemistry Department, Texas A&M University, College Station, TX 77843, USA
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Navarro-Sastre A, Tort F, Stehling O, Uzarska MA, Arranz JA, Del Toro M, Labayru MT, Landa J, Font A, Garcia-Villoria J, Merinero B, Ugarte M, Gutierrez-Solana LG, Campistol J, Garcia-Cazorla A, Vaquerizo J, Riudor E, Briones P, Elpeleg O, Ribes A, Lill R. A fatal mitochondrial disease is associated with defective NFU1 function in the maturation of a subset of mitochondrial Fe-S proteins. Am J Hum Genet 2011; 89:656-67. [PMID: 22077971 DOI: 10.1016/j.ajhg.2011.10.005] [Citation(s) in RCA: 225] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 10/07/2011] [Accepted: 10/13/2011] [Indexed: 01/20/2023] Open
Abstract
We report on ten individuals with a fatal infantile encephalopathy and/or pulmonary hypertension, leading to death before the age of 15 months. Hyperglycinemia and lactic acidosis were common findings. Glycine cleavage system and pyruvate dehydrogenase complex (PDHC) activities were low. Homozygosity mapping revealed a perfectly overlapping homozygous region of 1.24 Mb corresponding to chromosome 2 and led to the identification of a homozygous missense mutation (c.622G > T) in NFU1, which encodes a conserved protein suggested to participate in Fe-S cluster biogenesis. Nine individuals were homozygous for this mutation, whereas one was compound heterozygous for this and a splice-site (c.545 + 5G > A) mutation. The biochemical phenotype suggested an impaired activity of the Fe-S enzyme lipoic acid synthase (LAS). Direct measurement of protein-bound lipoic acid in individual tissues indeed showed marked decreases. Upon depletion of NFU1 by RNA interference in human cell culture, LAS and, in turn, PDHC activities were largely diminished. In addition, the amount of succinate dehydrogenase, but no other Fe-S proteins, was decreased. In contrast, depletion of the general Fe-S scaffold protein ISCU severely affected assembly of all tested Fe-S proteins, suggesting that NFU1 performs a specific function in mitochondrial Fe-S cluster maturation. Similar biochemical effects were observed in Saccharomyces cerevisiae upon deletion of NFU1, resulting in lower lipoylation and SDH activity. Importantly, yeast Nfu1 protein carrying the individuals' missense mutation was functionally impaired. We conclude that NFU1 functions as a late-acting maturation factor for a subset of mitochondrial Fe-S proteins.
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Affiliation(s)
- Aleix Navarro-Sastre
- Division of Inborn Errors of Metabolism, Department of Biochemistry and Molecular Genetics, Hospital Clinic, Instituto de Investigación Biomédica Pi Sunyer, 08028 Barcelona, Spain
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Mühlenhoff U, Richter N, Pines O, Pierik AJ, Lill R. Specialized function of yeast Isa1 and Isa2 proteins in the maturation of mitochondrial [4Fe-4S] proteins. J Biol Chem 2011; 286:41205-41216. [PMID: 21987576 DOI: 10.1074/jbc.m111.296152] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Most eukaryotes contain iron-sulfur cluster (ISC) assembly proteins related to Saccharomyces cerevisiae Isa1 and Isa2. We show here that Isa1 but not Isa2 can be functionally replaced by the bacterial relatives IscA, SufA, and ErpA. The specific function of these "A-type" ISC proteins within the framework of mitochondrial and bacterial Fe/S protein biogenesis is still unresolved. In a comprehensive in vivo analysis, we show that S. cerevisiae Isa1 and Isa2 form a complex that is required for maturation of mitochondrial [4Fe-4S] proteins, including aconitase and homoaconitase. In contrast, Isa1-Isa2 were dispensable for the generation of mitochondrial [2Fe-2S] proteins and cytosolic [4Fe-4S] proteins. Targeting of bacterial [2Fe-2S] and [4Fe-4S] ferredoxins to yeast mitochondria further supported this specificity. Isa1 and Isa2 proteins are shown to bind iron in vivo, yet the Isa1-Isa2-bound iron was not needed as a donor for de novo assembly of the [2Fe-2S] cluster on the general Fe/S scaffold proteins Isu1-Isu2. Upon depletion of the ISC assembly factor Iba57, which specifically interacts with Isa1 and Isa2, or in the absence of the major mitochondrial [4Fe-4S] protein aconitase, iron accumulated on the Isa proteins. These results suggest that the iron bound to the Isa proteins is required for the de novo synthesis of [4Fe-4S] clusters in mitochondria and for their insertion into apoproteins in a reaction mediated by Iba57. Taken together, these findings define Isa1, Isa2, and Iba57 as a specialized, late-acting ISC assembly subsystem that is specifically dedicated to the maturation of mitochondrial [4Fe-4S] proteins.
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Affiliation(s)
- Ulrich Mühlenhoff
- Institut für Zytobiologie und Zytopathologie, Philipps-Universität Marburg, Robert-Koch Strasse 6, 35032 Marburg, Germany
| | - Nadine Richter
- Institut für Zytobiologie und Zytopathologie, Philipps-Universität Marburg, Robert-Koch Strasse 6, 35032 Marburg, Germany
| | - Ophry Pines
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem 91120, Israel
| | - Antonio J Pierik
- Institut für Zytobiologie und Zytopathologie, Philipps-Universität Marburg, Robert-Koch Strasse 6, 35032 Marburg, Germany
| | - Roland Lill
- Institut für Zytobiologie und Zytopathologie, Philipps-Universität Marburg, Robert-Koch Strasse 6, 35032 Marburg, Germany.
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Xu XM, Møller SG. Iron-sulfur clusters: biogenesis, molecular mechanisms, and their functional significance. Antioxid Redox Signal 2011; 15:271-307. [PMID: 20812788 DOI: 10.1089/ars.2010.3259] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Iron-sulfur clusters [Fe-S] are small, ubiquitous inorganic cofactors representing one of the earliest catalysts during biomolecule evolution and are involved in fundamental biological reactions, including regulation of enzyme activity, mitochondrial respiration, ribosome biogenesis, cofactor biogenesis, gene expression regulation, and nucleotide metabolism. Although simple in structure, [Fe-S] biogenesis requires complex protein machineries and pathways for assembly. [Fe-S] are assembled from cysteine-derived sulfur and iron onto scaffold proteins followed by transfer to recipient apoproteins. Several predominant iron-sulfur biogenesis systems have been identified, including nitrogen fixation (NIF), sulfur utilization factor (SUF), iron-sulfur cluster (ISC), and cytosolic iron-sulfur protein assembly (CIA), and many protein components have been identified and characterized. In eukaryotes ISC is mainly localized to mitochondria, cytosolic iron-sulfur protein assembly to the cytosol, whereas plant sulfur utilization factor is localized mainly to plastids. Because of this spatial separation, evidence suggests cross-talk mediated by organelle export machineries and dual targeting mechanisms. Although research efforts in understanding iron-sulfur biogenesis has been centered on bacteria, yeast, and plants, recent efforts have implicated inappropriate [Fe-S] biogenesis to underlie many human diseases. In this review we detail our current understanding of [Fe-S] biogenesis across species boundaries highlighting evolutionary conservation and divergence and assembling our knowledge into a cellular context.
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Affiliation(s)
- Xiang Ming Xu
- Centre for Organelle Research CORE, University of Stavanger, Norway
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Holmqvist M, Lindberg P, Agervald A, Stensjö K, Lindblad P. Transcript analysis of the extended hyp-operon in the cyanobacteria Nostoc sp. strain PCC 7120 and Nostoc punctiforme ATCC 29133. BMC Res Notes 2011; 4:186. [PMID: 21672234 PMCID: PMC3126725 DOI: 10.1186/1756-0500-4-186] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Accepted: 06/14/2011] [Indexed: 11/13/2022] Open
Abstract
Background Cyanobacteria harbor two [NiFe]-type hydrogenases consisting of a large and a small subunit, the Hup- and Hox-hydrogenase, respectively. Insertion of ligands and correct folding of nickel-iron hydrogenases require assistance of accessory maturation proteins (encoded by the hyp-genes). The intergenic region between the structural genes encoding the uptake hydrogenase (hupSL) and the accessory maturation proteins (hyp genes) in the cyanobacteria Nostoc PCC 7120 and N. punctiforme were analysed using molecular methods. Findings The five ORFs, located in between the uptake hydrogenase structural genes and the hyp-genes, can form a transcript with the hyp-genes. An identical genomic localization of these ORFs are found in other filamentous, N2-fixing cyanobacterial strains. In N. punctiforme and Nostoc PCC 7120 the ORFs upstream of the hyp-genes showed similar transcript level profiles as hupS (hydrogenase structural gene), nifD (nitrogenase structural gene), hypC and hypF (accessory hydrogenase maturation genes) after nitrogen depletion. In silico analyzes showed that these ORFs in N. punctiforme harbor the same conserved regions as their homologues in Nostoc PCC 7120 and that they, like their homologues in Nostoc PCC 7120, can be transcribed together with the hyp-genes forming a larger extended hyp-operon. DNA binding studies showed interactions of the transcriptional regulators CalA and CalB to the promoter regions of the extended hyp-operon in N. punctiforme and Nostoc PCC 7120. Conclusions The five ORFs upstream of the hyp-genes in several filamentous N2-fixing cyanobacteria have an identical genomic localization, in between the genes encoding the uptake hydrogenase and the maturation protein genes. In N. punctiforme and Nostoc PCC 7120 they are transcribed as one operon and may form transcripts together with the hyp-genes. The expression pattern of the five ORFs within the extended hyp-operon in both Nostoc punctiforme and Nostoc PCC 7120 is similar to the expression patterns of hupS, nifD, hypF and hypC. CalA, a known transcription factor, interacts with the promoter region between hupSL and the five ORFs in the extended hyp-operon in both Nostoc strains.
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Affiliation(s)
- Marie Holmqvist
- Department of Photochemistry and Molecular Science, The Ångström Laboratories, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden.
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Balk J, Pilon M. Ancient and essential: the assembly of iron-sulfur clusters in plants. TRENDS IN PLANT SCIENCE 2011; 16:218-26. [PMID: 21257336 DOI: 10.1016/j.tplants.2010.12.006] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 12/10/2010] [Accepted: 12/21/2010] [Indexed: 05/18/2023]
Abstract
In plants iron-sulfur (Fe-S) proteins are found in the plastids, mitochondria, cytosol and nucleus, where they are essential for numerous physiological and developmental processes. Recent mutant studies, mostly in Arabidopsis thaliana, have identified three pathways for the assembly of Fe-S clusters. The plastids harbor the SUF (sulfur mobilization) pathway and operate independently, whereas cluster assembly in the cytosol depends on the emerging CIA (cytosolic iron-sulfur cluster assembly) pathway and mitochondria. The latter organelles use the ISC (iron-sulfur cluster) assembly pathway. In all three pathways the assembly process can be divided into a first stage where S and Fe are combined on a scaffold protein, and a second stage in which the Fe-S cluster is transferred to a target protein. The second stage might involve different carrier proteins with specialized functions.
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Affiliation(s)
- Janneke Balk
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK.
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In vivo evidence for the iron-binding activity of an iron-sulfur cluster assembly protein IscA in Escherichia coli. Biochem J 2011; 432:429-36. [PMID: 20942799 DOI: 10.1042/bj20101507] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
IscA is a key member of the iron-sulfur cluster assembly machinery in prokaryotic and eukaryotic organisms; however, the physiological function of IscA still remains elusive. In the present paper we report the in vivo evidence demonstrating the iron-binding activity of IscA in Escherichia coli cells. Supplement of exogenous iron (1 μM) in M9 minimal medium is sufficient to maximize the iron binding in IscA expressed in E. coli cells under aerobic growth conditions. In contrast, IscU, an iron-sulfur cluster assembly scaffold protein, or CyaY, a bacterial frataxin homologue, fails to bind any iron in E. coli cells under the same experimental conditions. Interestingly, the strong iron-binding activity of IscA is greatly diminished in E. coli cells under anaerobic growth conditions. Additional studies reveal that oxygen in medium promotes the iron binding in IscA, and that the iron binding in IscA in turn prevents formation of biologically inaccessible ferric hydroxide under aerobic conditions. Consistent with the differential iron-binding activity of IscA under aerobic and anaerobic conditions, we find that IscA and its paralogue SufA are essential for the iron-sulfur cluster assembly in E. coli cells under aerobic growth conditions, but not under anaerobic growth conditions. The results provide in vivo evidence that IscA may act as an iron chaperone for the biogenesis of iron-sulfur clusters in E. coli cells under aerobic conditions.
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Polyphasic characterization of a thermotolerant siderophilic filamentous cyanobacterium that produces intracellular iron deposits. Appl Environ Microbiol 2010; 76:6664-72. [PMID: 20709851 DOI: 10.1128/aem.00662-10] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Despite the high potential for oxidative stress stimulated by reduced iron, contemporary iron-depositing hot springs with circum-neutral pH are intensively populated with cyanobacteria. Therefore, studies of the physiology, diversity, and phylogeny of cyanobacteria inhabiting iron-depositing hot springs may provide insights into the contribution of cyanobacteria to iron redox cycling in these environments and new mechanisms of oxidative stress mitigation. In this study the morphology, ultrastructure, physiology, and phylogeny of a novel cyanobacterial taxon, JSC-1, isolated from an iron-depositing hot spring, were determined. The JSC-1 strain has been deposited in ATCC under the name Marsacia ferruginose, accession number BAA-2121. Strain JSC-1 represents a new operational taxonomical unit (OTU) within Leptolyngbya sensu lato. Strain JSC-1 exhibited an unusually high ratio between photosystem (PS) I and PS II, was capable of complementary chromatic adaptation, and is apparently capable of nitrogen fixation. Furthermore, it synthesized a unique set of carotenoids, but only chlorophyll a. Strain JSC-1 not only required high levels of Fe for growth (≥40 μM), but it also accumulated large amounts of extracellular iron in the form of ferrihydrite and intracellular iron in the form of ferric phosphates. Collectively, these observations provide insights into the physiological strategies that might have allowed cyanobacteria to develop and proliferate in Fe-rich, circum-neutral environments.
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Abstract
The broad range of cellular activities carried out by Fe-S proteins means that they have a central role in the life of most organisms. At the interface between biology and chemistry, studies of bacterial Fe-S protein biogenesis have taken advantage of the specific approaches of each field and have begun to reveal the molecular mechanisms involved. The multiprotein systems that are required to build Fe-S proteins have been identified, but the in vivo roles of some of the components remain to be clarified. The way in which cellular Fe-S cluster trafficking pathways are organized remains a key issue for future studies.
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Abstract
A human homologue of the iron-sulfur cluster assembly protein IscA (hIscA1) has been cloned and expressed in Escherichia coli cells. The UV-visible absorption and EPR (electron paramagnetic resonance) measurements reveal that hIscA1 purified from E. coli cells contains a mononuclear iron centre and that the iron binding in hIscA1 expressed in E. coli cells can be further modulated by the iron content in the cell growth medium. Additional studies show that purified hIscA1 binds iron with an iron association constant of approx. 2x1019 M-1, and that the iron-bound hIscA1 is able to provide the iron for the iron-sulfur cluster assembly in a proposed scaffold protein, IscU of E. coli, in vitro. The complementation experiments indicate that hIscA1 can partially substitute for IscA in restoring the cell growth of E. coli in the M9 minimal medium under aerobic conditions. The results suggest that hIscA1, like E. coli IscA, is an iron-binding protein that may act as an iron chaperone for biogenesis of iron-sulfur clusters.
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