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An L, Xu M, Hong M, Zhao L, Wei A, Luo X, Shi K, Zheng S, Li M. A novel antimony metallochaperone AntC in Comamonas testosteroni JL40 and its application in antimony immobilization. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 911:168815. [PMID: 38000745 DOI: 10.1016/j.scitotenv.2023.168815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 11/11/2023] [Accepted: 11/21/2023] [Indexed: 11/26/2023]
Abstract
The microbial metabolism of toxic antimony (Sb) and the bioremediation of Sb-contaminated environments have attracted significant attention recently. This study identified an Sb(III) metallochaperone AntC in the Sb(III) efflux operon antRCA of Comamonas testosteroni JL40. The deletion of AntC significantly increased the intracellular Sb content in strain JL40 and concomitantly diminished resistance to Sb(III). By contrast, the complementary expression of AntC in the knockout strain resulted in a substantial recovery of Sb(III) resistance. The site-directed mutagenesis assay demonstrated the three conserved cysteine (Cys) residues (Cys30, Cys34, and Cys36) play an essential role in the binding of Sb(III) to AntC and its transfer. The function of the metallochaperone AntC was further investigated in an Sb(III) sensitive bacterium Escherichia coli AW3110 (Δars). The co-expression of AntC and AntA in AW3110 cells resulted in a four-fold increase in minimum inhibitory concentrations (MICs) toward Sb(III), while the intracellular Sb content decreased five-fold compared to cells expressing AntA alone. In addition, a genetically modified E. coli strain was engineered to co-express AntC and the Sb uptake protein GlpF, showing an eight-fold increase in Sb absorption and achieving a remarkable 90% removal of Sb from the solution. This engineered strain was also applied in a hydroponic experiment, displaying a significant 80% reduction in Sb uptake by rice seedlings. This finding provides new insights into the mechanisms of bacterial Sb detoxification and a potential bioremediation strategy for Sb pollution.
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Affiliation(s)
- Lijin An
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Mingzhu Xu
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Mengjuan Hong
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Lipeng Zhao
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Ao Wei
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Xiong Luo
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Kaixiang Shi
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Shixue Zheng
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Mingshun Li
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China.
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Zhang T, Liu L, Zhi JR, Jia YL, Yue WB, Zeng G, Li DY. Copper Chaperone for Superoxide Dismutase FoCCS1 in Frankliniella occidentalis May Be Associated with Feeding Adaptation after Host Shifting. INSECTS 2022; 13:782. [PMID: 36135483 PMCID: PMC9501208 DOI: 10.3390/insects13090782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 08/12/2022] [Accepted: 08/18/2022] [Indexed: 06/16/2023]
Abstract
Western flower thrips (Frankliniella occidentalis) pose a serious threat to the global vegetable and flower crop production. The regulatory mechanism for superoxide dismutase (SOD) in the feeding adaptation of F. occidentalis after host shifting remains unclear. In this study, the copper chaperone for SOD (CCS) and manganese SOD (MnSOD) genes in F. occidentalis were cloned, and their expression levels at different developmental stages was determined. The mRNA expression of FoCCS1 and FoMnSOD2 in F. occidentalis second-instar larvae and adult females of F1, F2, and F3 generations was analyzed after shifting the thrips to kidney bean and broad bean plants, respectively. The F2 and F3 second-instar larvae and F2 adult females showed significantly upregulated FoCCS1 mRNA expression after shifting to kidney bean plants. The F1 second-instar larvae and F2 adult females showed significantly upregulated FoCCS1 mRNA expression after shifting to broad bean plants. The RNA interference significantly downregulated the FoCCS1 mRNA expression levels and adult females showed significantly inhibited SOD activity after shifting to kidney bean and broad bean plants. F. occidentalis adult females subjected to RNA interference and released on kidney bean and broad bean leaves for rearing, respectively, significantly reduced the survival rate and fecundity. These findings suggest that FoCCS1 plays an active role in regulating the feeding adaptation ability of F. occidentalis after host shifting.
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Affiliation(s)
- Tao Zhang
- Institute of Entomology, Guizhou University, Guiyang 550025, China
- Guizhou Provincial Key Laboratory for Agricultural Pest Management in the Mountainous Region, Guiyang 550025, China
| | - Li Liu
- Institute of Entomology, Guizhou University, Guiyang 550025, China
- Guizhou Provincial Key Laboratory for Agricultural Pest Management in the Mountainous Region, Guiyang 550025, China
| | - Jun-Rui Zhi
- Institute of Entomology, Guizhou University, Guiyang 550025, China
- Guizhou Provincial Key Laboratory for Agricultural Pest Management in the Mountainous Region, Guiyang 550025, China
| | - Yu-Lian Jia
- Institute of Entomology, Guizhou University, Guiyang 550025, China
- Guizhou Provincial Key Laboratory for Agricultural Pest Management in the Mountainous Region, Guiyang 550025, China
| | - Wen-Bo Yue
- Institute of Entomology, Guizhou University, Guiyang 550025, China
- Guizhou Provincial Key Laboratory for Agricultural Pest Management in the Mountainous Region, Guiyang 550025, China
| | - Guang Zeng
- Institute of Entomology, Guizhou University, Guiyang 550025, China
- Guizhou Provincial Key Laboratory for Agricultural Pest Management in the Mountainous Region, Guiyang 550025, China
| | - Ding-Yin Li
- Institute of Entomology, Guizhou University, Guiyang 550025, China
- Guizhou Provincial Key Laboratory for Agricultural Pest Management in the Mountainous Region, Guiyang 550025, China
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The Copper Chaperone CcsA, Coupled with Superoxide Dismutase SodA, Mediates the Oxidative Stress Response in Aspergillus fumigatus. Appl Environ Microbiol 2021; 87:e0101321. [PMID: 34160279 DOI: 10.1128/aem.01013-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Superoxide dismutases (SODs) are important metalloenzymes that protect fungal pathogens against the toxic effects of reactive oxygen species (ROS) generated by host defense mechanisms during the infection process. The activation of Cu/Zn-SOD1 is found to be dependent on copper chaperone for SOD1 (Ccs1). However, the role of the Ccs1 ortholog in the human pathogen Aspergillus fumigatus and how these SODs coordinate to mediate oxidative stress response remain elusive. Here, we demonstrated that A. fumigatus CcsA, a Saccharomyces cerevisiae Ccs1 ortholog, is required for cells in response to oxidative response and the activation of Sod1. Deletion of ccsA resulted in increased ROS accumulation and enhanced sensitivity to oxidative stress due to the loss of SodA activity. Molecular characterization of CcsA revealed that the conserved CXC motif is required not only for the physical interaction with SodA but also for the oxidative stress adaption. Notably, addition of Mn2+ or overexpression of cytoplasmic Mn-SodC could rescue the defects of the ccsA or sodA deletion mutant, indicating the important role of Mn2+ and Mn-SodC in ROS detoxification; however, deletion of the CcsA-SodA complex could not affect A. fumigatus virulence. Collectively, our findings demonstrate that CcsA functions as a Cu/Zn-Sod1 chaperone that participates in the adaptation to oxidative stress in A. fumigatus and provide a better understanding of the CcsA-SodA complex-mediated oxidative stress response in filamentous fungi. IMPORTANCE Reactive oxygen species (ROS) produced by phagocytes have been reported to participate in the killing of fungal pathogens. Superoxide dismutases (SODs) are considered to be the first line of defense against superoxide anions. Characterizing the regulatory mechanisms of SOD activation is important for understanding how fungi adapt to oxidative stress in hosts. Our findings demonstrated that CcsA functions as a SodA chaperone in A. fumigatus and that the conserved CXC motif within CcsA is required for its interaction with SodA and the CcsA-SodA-mediated oxidative response. These data may provide new insights into how fungal pathogens adapt to oxidative stress via the CcsA-SodA complex.
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Trist BG, Hilton JB, Hare DJ, Crouch PJ, Double KL. Superoxide Dismutase 1 in Health and Disease: How a Frontline Antioxidant Becomes Neurotoxic. Angew Chem Int Ed Engl 2021; 60:9215-9246. [PMID: 32144830 PMCID: PMC8247289 DOI: 10.1002/anie.202000451] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Indexed: 12/11/2022]
Abstract
Cu/Zn superoxide dismutase (SOD1) is a frontline antioxidant enzyme catalysing superoxide breakdown and is important for most forms of eukaryotic life. The evolution of aerobic respiration by mitochondria increased cellular production of superoxide, resulting in an increased reliance upon SOD1. Consistent with the importance of SOD1 for cellular health, many human diseases of the central nervous system involve perturbations in SOD1 biology. But far from providing a simple demonstration of how disease arises from SOD1 loss-of-function, attempts to elucidate pathways by which atypical SOD1 biology leads to neurodegeneration have revealed unexpectedly complex molecular characteristics delineating healthy, functional SOD1 protein from that which likely contributes to central nervous system disease. This review summarises current understanding of SOD1 biology from SOD1 genetics through to protein function and stability.
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Affiliation(s)
- Benjamin G. Trist
- Brain and Mind Centre and Discipline of PharmacologyThe University of Sydney, CamperdownSydneyNew South Wales2050Australia
| | - James B. Hilton
- Department of Pharmacology and TherapeuticsThe University of MelbourneParkvilleVictoria3052Australia
| | - Dominic J. Hare
- Brain and Mind Centre and Discipline of PharmacologyThe University of Sydney, CamperdownSydneyNew South Wales2050Australia
- School of BioSciencesThe University of MelbourneParkvilleVictoria3052Australia
- Atomic Medicine InitiativeThe University of Technology SydneyBroadwayNew South Wales2007Australia
| | - Peter J. Crouch
- Department of Pharmacology and TherapeuticsThe University of MelbourneParkvilleVictoria3052Australia
| | - Kay L. Double
- Brain and Mind Centre and Discipline of PharmacologyThe University of Sydney, CamperdownSydneyNew South Wales2050Australia
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Furukawa Y. Good and Bad of Cu/Zn-Superoxide Dismutase Controlled by Metal Ions and Disulfide Bonds. CHEM LETT 2021. [DOI: 10.1246/cl.200770] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Yoshiaki Furukawa
- Department of Chemistry, Keio University, 3-14-1 Hiyoshi, Kohoku, Kanagawa 223-8522, Japan
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Trist BG, Hilton JB, Hare DJ, Crouch PJ, Double KL. Superoxide Dismutase 1 in Health and Disease: How a Frontline Antioxidant Becomes Neurotoxic. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202000451] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Benjamin G. Trist
- Brain and Mind Centre and Discipline of Pharmacology The University of Sydney, Camperdown Sydney New South Wales 2050 Australia
| | - James B. Hilton
- Department of Pharmacology and Therapeutics The University of Melbourne Parkville Victoria 3052 Australia
| | - Dominic J. Hare
- Brain and Mind Centre and Discipline of Pharmacology The University of Sydney, Camperdown Sydney New South Wales 2050 Australia
- School of BioSciences The University of Melbourne Parkville Victoria 3052 Australia
- Atomic Medicine Initiative The University of Technology Sydney Broadway New South Wales 2007 Australia
| | - Peter J. Crouch
- Department of Pharmacology and Therapeutics The University of Melbourne Parkville Victoria 3052 Australia
| | - Kay L. Double
- Brain and Mind Centre and Discipline of Pharmacology The University of Sydney, Camperdown Sydney New South Wales 2050 Australia
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Boyd SD, Ullrich MS, Skopp A, Winkler DD. Copper Sources for Sod1 Activation. Antioxidants (Basel) 2020; 9:antiox9060500. [PMID: 32517371 PMCID: PMC7346115 DOI: 10.3390/antiox9060500] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/12/2020] [Accepted: 06/01/2020] [Indexed: 02/06/2023] Open
Abstract
Copper ions (i.e., copper) are a critical part of several cellular processes, but tight regulation of copper levels and trafficking are required to keep the cell protected from this highly reactive transition metal. Cu, Zn superoxide dismutase (Sod1) protects the cell from the accumulation of radical oxygen species by way of the redox cycling activity of copper in its catalytic center. Multiple posttranslational modification events, including copper incorporation, are reliant on the copper chaperone for Sod1 (Ccs). The high-affinity copper uptake protein (Ctr1) is the main entry point of copper into eukaryotic cells and can directly supply copper to Ccs along with other known intracellular chaperones and trafficking molecules. This review explores the routes of copper delivery that are utilized to activate Sod1 and the usefulness and necessity of each.
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Ge Y, Wang L, Li D, Zhao C, Li J, Liu T. Exploring the Extended Biological Functions of the Human Copper Chaperone of Superoxide Dismutase 1. Protein J 2020; 38:463-471. [PMID: 31140034 DOI: 10.1007/s10930-019-09824-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The human copper chaperone of SOD1 (designated as CCS) was discovered more than two decades ago. It is an important copper binding protein and a homolog of Saccharomyces cerevisiae LYS7. To date, no studies have systematically or specifically elaborated on the functional development of CCS. This review summarizes the essential information about CCS, such as its localization, 3D structure, and copper binding ability. An emphasis is placed on its interacting protein partners and its biological functions in vivo and in vitro. Three-dimensional structural analysis revealed that CCS is composed of three domains. Its primary molecular function is the delivery of copper to SOD1 and activation of SOD1. It has also been reported to bind to XIAP, Mia40, and X11α, and other proteins. Through these protein partners, CCS is implicated in several vital biological processes in vivo, such as copper homeostasis, apoptosis, angiogenesis and oxidative stress. This review is anticipated to assist scientists in systematically understanding the latest research developments of CCS for facilitating the development of new therapeutics targeting CCS in the future.
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Affiliation(s)
- Yan Ge
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, No. 168 Huaguan Road, Chenghua District, Chengdu, 610052, China.,International Phage Drug Research Center, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu, China
| | - Lu Wang
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, No. 168 Huaguan Road, Chenghua District, Chengdu, 610052, China. .,International Phage Drug Research Center, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu, China.
| | - Duanhua Li
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, No. 168 Huaguan Road, Chenghua District, Chengdu, 610052, China.,International Phage Drug Research Center, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu, China
| | - Chen Zhao
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, No. 168 Huaguan Road, Chenghua District, Chengdu, 610052, China.,International Phage Drug Research Center, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu, China
| | - Jinjun Li
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, No. 168 Huaguan Road, Chenghua District, Chengdu, 610052, China.,International Phage Drug Research Center, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu, China
| | - Tao Liu
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, No. 168 Huaguan Road, Chenghua District, Chengdu, 610052, China.,International Phage Drug Research Center, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu, China
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9
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Schatzman SS, Peterson RL, Teka M, He B, Cabelli DE, Cormack BP, Culotta VC. Copper-only superoxide dismutase enzymes and iron starvation stress in Candida fungal pathogens. J Biol Chem 2019; 295:570-583. [PMID: 31806705 DOI: 10.1074/jbc.ra119.011084] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 11/27/2019] [Indexed: 12/11/2022] Open
Abstract
Copper (Cu)-only superoxide dismutases (SOD) represent a newly characterized class of extracellular SODs important for virulence of several fungal pathogens. Previous studies of the Cu-only enzyme SOD5 from the opportunistic fungal pathogen Candida albicans have revealed that the active-site structure and Cu binding of SOD5 strongly deviate from those of Cu/Zn-SODs in its animal hosts, making Cu-only SODs a possible target for future antifungal drug design. C. albicans also expresses a Cu-only SOD4 that is highly similar in sequence to SOD5, but is poorly characterized. Here, we compared the biochemical, biophysical, and cell biological properties of C. albicans SOD4 and SOD5. Analyzing the recombinant proteins, we found that, similar to SOD5, Cu-only SOD4 can react with superoxide at rates approaching diffusion limits. Both SODs were monomeric and they exhibited similar binding affinities for their Cu cofactor. In C. albicans cultures, SOD4 and SOD5 were predominantly cell wall proteins. Despite these similarities, the SOD4 and SOD5 genes strongly differed in transcriptional regulation. SOD5 was predominantly induced during hyphal morphogenesis, together with a fungal burst in reactive oxygen species. Conversely, SOD4 expression was specifically up-regulated by iron (Fe) starvation and controlled by the Fe-responsive transcription factor SEF1. Interestingly, Candida tropicalis and the emerging fungal pathogen Candida auris contain a single SOD5-like SOD rather than a pair, and in both fungi, this SOD was induced by Fe starvation. This unexpected link between Fe homeostasis and extracellular Cu-SODs may help many fungi adapt to Fe-limited conditions of their hosts.
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Affiliation(s)
- Sabrina S Schatzman
- Department of Biochemistry and Molecular Biology, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Ryan L Peterson
- Department of Biochemistry and Molecular Biology, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Mieraf Teka
- Department of Biochemistry and Molecular Biology, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Bixi He
- Department of Biochemistry and Molecular Biology, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Diane E Cabelli
- Chemistry Department, Brookhaven National Laboratories, Upton, New York 11973
| | - Brendan P Cormack
- Department of Molecular Biology and Genetics, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Valeria C Culotta
- Department of Biochemistry and Molecular Biology, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205.
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Abstract
Few proteins have come under such intense scrutiny as superoxide dismutase-1 (SOD1). For almost a century, scientists have dissected its form, function and then later its malfunction in the neurodegenerative disease amyotrophic lateral sclerosis (ALS). We now know SOD1 is a zinc and copper metalloenzyme that clears superoxide as part of our antioxidant defence and respiratory regulation systems. The possibility of reduced structural integrity was suggested by the first crystal structures of human SOD1 even before deleterious mutations in the sod1 gene were linked to the ALS. This concept evolved in the intervening years as an impressive array of biophysical studies examined the characteristics of mutant SOD1 in great detail. We now recognise how ALS-related mutations perturb the SOD1 maturation processes, reduce its ability to fold and reduce its thermal stability and half-life. Mutant SOD1 is therefore predisposed to monomerisation, non-canonical self-interactions, the formation of small misfolded oligomers and ultimately accumulation in the tell-tale insoluble inclusions found within the neurons of ALS patients. We have also seen that several post-translational modifications could push wild-type SOD1 down this toxic pathway. Recently we have come to view ALS as a prion-like disease where both the symptoms, and indeed SOD1 misfolding itself, are transmitted to neighbouring cells. This raises the possibility of intervention after the initial disease presentation. Several small-molecule and biologic-based strategies have been devised which directly target the SOD1 molecule to change the behaviour thought to be responsible for ALS. Here we provide a comprehensive review of the many biophysical advances that sculpted our view of SOD1 biology and the recent work that aims to apply this knowledge for therapeutic outcomes in ALS.
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Zhang H, Gao X, Zhi Y, Li X, Zhang Q, Niu J, Wang J, Zhai H, Zhao N, Li J, Liu Q, He S. A non-tandem CCCH-type zinc-finger protein, IbC3H18, functions as a nuclear transcriptional activator and enhances abiotic stress tolerance in sweet potato. THE NEW PHYTOLOGIST 2019; 223:1918-1936. [PMID: 31091337 DOI: 10.1111/nph.15925] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Accepted: 05/08/2019] [Indexed: 05/21/2023]
Abstract
CCCH-type zinc-finger proteins play essential roles in regulating plant development and stress responses. However, the molecular and functional properties of non-tandem CCCH-type zinc-finger (non-TZF) proteins have been rarely characterized in plants. Here, we report the biological and molecular characterization of a sweet potato non-TZF gene, IbC3H18. We show that IbC3H18 exhibits tissue- and abiotic stress-specific expression, and could be effectively induced by abiotic stresses, including NaCl, polyethylene glycol (PEG) 6000, H2 O2 and abscisic acid (ABA) in sweet potato. Accordingly, overexpression of IbC3H18 led to increased, whereas knock-down of IbC3H18 resulted in decreased tolerance of sweet potato to salt, drought and oxidation stresses. In addition, IbC3H18 functions as a nuclear transcriptional activator and regulates the expression of a range of abiotic stress-responsive genes involved in reactive oxygen species (ROS) scavenging, ABA signaling, photosynthesis and ion transport pathways. Moreover, our data demonstrate that IbC3H18 physically interacts with IbPR5, and that overexpression of IbPR5 enhances salt and drought tolerance in transgenic tobacco plants. Collectively, our data indicate that IbC3H18 functions in enhancing abiotic stress tolerance in sweet potato, which may serve as a candidate gene for use in improving abiotic stress resistance in crops.
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Affiliation(s)
- Huan Zhang
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis & Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy & Biotechnology, China Agricultural University, Beijing, 100193, China
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Xiaoru Gao
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis & Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy & Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Yuhai Zhi
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis & Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy & Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Xu Li
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis & Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy & Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Qian Zhang
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis & Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy & Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Jinbiao Niu
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis & Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy & Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Jun Wang
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis & Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy & Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Hong Zhai
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis & Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy & Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Ning Zhao
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis & Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy & Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Jigang Li
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Qingchang Liu
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis & Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy & Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Shaozhen He
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis & Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy & Biotechnology, China Agricultural University, Beijing, 100193, China
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12
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Copper accumulation in senescent cells: Interplay between copper transporters and impaired autophagy. Redox Biol 2018; 16:322-331. [PMID: 29579719 PMCID: PMC5953000 DOI: 10.1016/j.redox.2018.03.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 03/09/2018] [Accepted: 03/13/2018] [Indexed: 12/24/2022] Open
Abstract
Cellular senescence is characterized by irreversible growth arrest incurred through either replicative exhaustion or by pro-oncogenic cellular stressors (radioactivity, oxidative stress, oncogenic activation). The enrichment of senescent cells in tissues with age has been associated with tissue dyshomeostasis and age-related pathologies including cancers, neurodegenerative disorders (e.g. Alzheimer's, Parkinson's, etc.) and metabolic disorders (e.g. diabetes). We identified copper accumulation as being a universal feature of senescent cells [mouse embryonic fibroblasts (MEF), human prostate epithelial cells and human diploid fibroblasts] in vitro. Elevated copper in senescent MEFs was accompanied by elevated levels of high-affinity copper uptake protein 1 (Ctr1), diminished levels of copper-transporting ATPase 1 (Atp7a) (copper export) and enhanced antioxidant defence reflected by elevated levels of glutathione (GSH), superoxide dismutase 1 (SOD1) and glutaredoxin 1 (Grx1). The levels of intracellular copper were further increased in senescent MEFs cultured in copper supplemented medium and in senescent Mottled Brindled (Mobr) MEFs lacking functional Atp7a. Finally, we demonstrated that the restoration/preservation of autophagic-lysosomal degradation in senescent MEFs following rapamycin treatment correlated with attenuation of copper accumulation in these cells despite a further decrease in Atp7a levels. This study for the first time establishes a link between Atp7a and the autophagic-lysosomal pathway, and a requirement for both to effect efficient copper export. Such a connection between cellular autophagy and copper homeostasis is significant, as both have emerged as important facets of age-associated degenerative disease. Copper accumulation is a feature of cellular senescence. Elevated copper in senescent cells is associated with impaired autophagic-lysosomal function. Restoration/preservation of lysosomal function attenuates copper accumulation. Both Atp7a and autophagic-lysosomal function are required for copper export.
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M. Fetherolf M, Boyd SD, Winkler DD, Winge DR. Oxygen-dependent activation of Cu,Zn-superoxide dismutase-1. Metallomics 2017; 9:1047-1059. [DOI: 10.1039/c6mt00298f] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Copper zinc superoxide dismutase (Sod1) is a critical enzyme in limiting reactive oxygen species in both the cytosol and the mitochondrial intermembrane space.
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Affiliation(s)
| | - Stefanie D. Boyd
- Department of Biological Sciences
- University of Texas at Dallas
- Richardson
- USA
| | - Duane D. Winkler
- Department of Biological Sciences
- University of Texas at Dallas
- Richardson
- USA
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14
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Farrugia MA, Wang B, Feig M, Hausinger RP. Mutational and Computational Evidence That a Nickel-Transfer Tunnel in UreD Is Used for Activation of Klebsiella aerogenes Urease. Biochemistry 2015; 54:6392-401. [PMID: 26401965 DOI: 10.1021/acs.biochem.5b00942] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nickel-containing urease from Klebsiella aerogenes requires four accessory proteins for proper active site metalation. The metallochaperone UreE delivers nickel to UreG, a GTPase that forms a UreD/UreF/UreG complex, which binds to urease apoprotein via UreD. Prior in silico analysis of the homologous, structurally characterized UreH/UreF/UreG complex from Helicobacter pylori identified a water tunnel originating at a likely nickel-binding motif in UreG, passing through UreF, and exiting UreH, suggestive of a role for the channel in providing the metal to urease apoprotein for its activation; however, no experimental support was reported for the significance of this tunnel. Here, specific variants were designed to disrupt a comparable 34.6 Å predicted internal tunnel, alternative channels, and surface sites for UreD. Cells producing a set of tunnel-disrupting variants of UreD exhibited greatly reduced urease specific activities, whereas other mutants had no appreciable effect on activity. Affinity pull-down studies of cell-free extracts from tunnel-disrupting mutant cultures showed no loss of UreD interactions with urease or UreF/UreG. The nickel contents of urease samples enriched from activity-deficient cultures were decreased, while zinc and iron incorporation increased. Molecular dynamics simulations revealed size restrictions in the internal channels of the UreD variants. These findings support the role of a molecular tunnel in UreD as a direct facilitator of nickel transfer into urease, illustrating a new paradigm in active site metallocenter assembly.
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Affiliation(s)
- Mark A Farrugia
- Department of Biochemistry and Molecular Biology, ‡Department of Chemistry, and §Department of Microbiology and Molecular Genetics, Michigan State University , East Lansing, Michigan 48824, United States
| | - Beibei Wang
- Department of Biochemistry and Molecular Biology, ‡Department of Chemistry, and §Department of Microbiology and Molecular Genetics, Michigan State University , East Lansing, Michigan 48824, United States
| | - Michael Feig
- Department of Biochemistry and Molecular Biology, ‡Department of Chemistry, and §Department of Microbiology and Molecular Genetics, Michigan State University , East Lansing, Michigan 48824, United States
| | - Robert P Hausinger
- Department of Biochemistry and Molecular Biology, ‡Department of Chemistry, and §Department of Microbiology and Molecular Genetics, Michigan State University , East Lansing, Michigan 48824, United States
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15
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Sun TS, Ju X, Gao HL, Wang T, Thiele DJ, Li JY, Wang ZY, Ding C. Reciprocal functions of Cryptococcus neoformans copper homeostasis machinery during pulmonary infection and meningoencephalitis. Nat Commun 2014; 5:5550. [DOI: 10.1038/ncomms6550] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 10/13/2014] [Indexed: 01/10/2023] Open
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16
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Sagasti S, Bernal MA, Sancho D, Del Castillo MB, Picorel R. Regulation of the chloroplastic copper chaperone (CCS) and cuprozinc superoxide dismutase (CSD2) by alternative splicing and copper excess in Glycine max. FUNCTIONAL PLANT BIOLOGY : FPB 2014; 41:144-155. [PMID: 32480974 DOI: 10.1071/fp13134] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 07/30/2013] [Indexed: 06/11/2023]
Abstract
Metal homeostasis is an important aspect of plant physiology, and the copper transport into the chloroplast and its fate after delivery is of special relevance for plants. In this work, the regulation of the chloroplastic copper chaperone for the cuprozinc superoxide dismutase (GmCCS) and its target, the cuprozinc superoxide dismutase (GmCSD2), was investigated in photosynthetic cell suspensions and entire plants from Glycine max (L.) Merr. Both genes were expressed in cell suspensions and in all plant tissues analysed, and their RNAs matured by alternative splicing with intron retention (IntronR). This mechanism generated a spliced and three non-spliced mRNAs in the case of GmCCS but only a spliced and a non-spliced mRNAs in GmCSD2. Copper excess strongly upregulated the expression of both fully spliced mRNAs but mostly unaffected the non-spliced forms. In entire plants, some tissue specificity was also observed depending on copper content status. At the protein level, the GmCCS was mostly unaffected but the GmCSD2 was strongly induced under copper excess in all subcellular fractions analysed, suggesting a post-transcriptional regulation for the former. This different protein regulation of the chaperone and its target may indicate some additional function for the CSD2 protein. In addition to its well-known superoxide dismutase (SOD) activity, it may also function as a metal sink in copper excess availability to avoid metal cell damage. Furthermore, the GmCCS seems to be present in the stroma only but the GmCSD2 was present in both stroma and thylakoids despite the general idea that the SOD enzymes are typically soluble stroma proteins. The presence of the SOD enzyme on the surface of the thylakoid membranes is reasonable considering that the superoxide radical (O2-) is preferentially formed at the acceptor side of the PSI.
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Affiliation(s)
- Sara Sagasti
- Department of Plant Nutrition, Estación Experimental de Aula Dei (EEAD), Consejo Superior de Investigaciones Científicas (CSIC), Carretera Montañana 1005, 50059 Zaragoza, Spain
| | - Mar A Bernal
- Department of Plant Nutrition, Estación Experimental de Aula Dei (EEAD), Consejo Superior de Investigaciones Científicas (CSIC), Carretera Montañana 1005, 50059 Zaragoza, Spain
| | - Diana Sancho
- Department of Plant Nutrition, Estación Experimental de Aula Dei (EEAD), Consejo Superior de Investigaciones Científicas (CSIC), Carretera Montañana 1005, 50059 Zaragoza, Spain
| | - Miren B Del Castillo
- Department of Plant Nutrition, Estación Experimental de Aula Dei (EEAD), Consejo Superior de Investigaciones Científicas (CSIC), Carretera Montañana 1005, 50059 Zaragoza, Spain
| | - Rafael Picorel
- Department of Plant Nutrition, Estación Experimental de Aula Dei (EEAD), Consejo Superior de Investigaciones Científicas (CSIC), Carretera Montañana 1005, 50059 Zaragoza, Spain
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Muid KA, Karakaya HÇ, Koc A. Absence of superoxide dismutase activity causes nuclear DNA fragmentation during the aging process. Biochem Biophys Res Commun 2014; 444:260-3. [PMID: 24462872 DOI: 10.1016/j.bbrc.2014.01.056] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 01/15/2014] [Indexed: 01/22/2023]
Abstract
Superoxide dismutases (SOD) serve as an important antioxidant defense mechanism in aerobic organisms, and deletion of these genes shortens the replicative life span in the budding yeast Saccharomyces cerevisiae. Even though involvement of superoxide dismutase enzymes in ROS scavenging and the aging process has been studied extensively in different organisms, analyses of DNA damages has not been performed for replicatively old superoxide dismutase deficient cells. In this study, we investigated the roles of SOD1, SOD2 and CCS1 genes in preserving genomic integrity in replicatively old yeast cells using the single cell comet assay. We observed that extend of DNA damage was not significantly different among the young cells of wild type, sod1Δ and sod2Δ strains. However, ccs1Δ mutants showed a 60% higher amount of DNA damage in the young stage compared to that of the wild type cells. The aging process increased the DNA damage rates 3-fold in the wild type and more than 5-fold in sod1Δ, sod2Δ, and ccs1Δ mutant cells. Furthermore, ROS levels of these strains showed a similar pattern to their DNA damage contents. Thus, our results confirm that cells accumulate DNA damages during the aging process and reveal that superoxide dismutase enzymes play a substantial role in preserving the genomic integrity in this process.
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Affiliation(s)
- Khandaker Ashfaqul Muid
- Izmir Institute of Technology, Department of Molecular Biology & Genetics, 35430 Urla, Izmir, Turkey
| | - Hüseyin Çaglar Karakaya
- Izmir Institute of Technology, Department of Molecular Biology & Genetics, 35430 Urla, Izmir, Turkey
| | - Ahmet Koc
- Izmir Institute of Technology, Department of Molecular Biology & Genetics, 35430 Urla, Izmir, Turkey.
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18
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Species-specific activation of Cu/Zn SOD by its CCS copper chaperone in the pathogenic yeast Candida albicans. J Biol Inorg Chem 2013; 19:595-603. [PMID: 24043471 DOI: 10.1007/s00775-013-1045-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 08/28/2013] [Indexed: 11/27/2022]
Abstract
Candida albicans is a pathogenic yeast of important public health relevance. Virulence of C. albicans requires a copper and zinc containing superoxide dismutase (SOD1), but the biology of C. albicans SOD1 is poorly understood. To this end, C. albicans SOD1 activation was examined in baker's yeast (Saccharomyces cerevisiae), a eukaryotic expression system that has proven fruitful for the study of SOD1 enzymes from invertebrates, plants, and mammals. In spite of the 80% similarity between S. cerevisiae and C. albicans SOD1 molecules, C. albicans SOD1 is not active in S. cerevisiae. The SOD1 appears incapable of productive interactions with the copper chaperone for SOD1 (CCS1) of S. cerevisiae. C. albicans SOD1 contains a proline at position 144 predicted to dictate dependence on CCS1. By mutation of this proline, C. albicans SOD1 gained activity in S. cerevisiae, and this activity was independent of CCS1. We identified a putative CCS1 gene in C. albicans and created heterozygous and homozygous gene deletions at this locus. Loss of CCS1 resulted in loss of SOD1 activity, consistent with its role as a copper chaperone. C. albicans CCS1 also restored activity to C. albicans SOD1 expressed in S. cerevisiae. C. albicans CCS1 is well adapted for activating its partner SOD1 from C. albicans, but not SOD1 from S. cerevisiae. In spite of the high degree of homology between the SOD1 and CCS1 molecules in these two fungal species, there exists a species-specific barrier in CCS-SOD interactions which may reflect the vastly different lifestyles of the pathogenic versus the noninfectious yeast.
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19
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Gamero-Sandemetrio E, Gómez-Pastor R, Matallana E. Zymogram profiling of superoxide dismutase and catalase activities allows Saccharomyces and non-Saccharomyces species differentiation and correlates to their fermentation performance. Appl Microbiol Biotechnol 2013; 97:4563-76. [DOI: 10.1007/s00253-012-4672-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 12/13/2012] [Accepted: 12/19/2012] [Indexed: 12/01/2022]
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20
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Using yeast models to probe the molecular basis of amyotrophic lateral sclerosis. Biochem Soc Trans 2011; 39:1482-7. [DOI: 10.1042/bst0391482] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
ALS (amyotrophic lateral sclerosis) is a fatal neurodegenerative disease attributable to the death of motor neurons. Associated with ALS are mutations in the genes encoding SOD1 (superoxide dismutase 1), FUS (fused in Sarcoma) protein and TDP-43 (TAR DNA-binding protein-43) each of which leads to aggregation of the respective protein. For example, the ALS-associated mutations in the hSOD1 (human SOD1) gene typically destabilize the native SOD homodimer, leading to misfolding, aggregation and degradation of SOD1. The ALS-associated pathology is not a consequence of the functional inactivation of SOD1 itself, but is rather due to a toxic gain-of-function triggered by mutant SOD1. Recently, the molecular basis of a number of human neurodegenerative diseases resulting from protein misfolding and aggregation, including fALS (familial ALS), was probed by using the baker's yeast, Saccharomyces cerevisiae, as a highly tractable model. Such studies have, for example, identified novel mutant SOD1-specific interactions and demonstrated that mutant SOD1 disrupts mitochondrial homoeostasis. Features of ALS associated with TDP-43 aggregation have also been recapitulated in S. cerevisiae including the identification of modulators of the toxicity of TDP-43. In this paper, we review recent studies of ALS pathogenesis using S. cerevisiae as a model organism and summarize the potential mechanisms involved in ALS progression.
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21
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Bleackley MR, Macgillivray RTA. Transition metal homeostasis: from yeast to human disease. Biometals 2011; 24:785-809. [PMID: 21479832 DOI: 10.1007/s10534-011-9451-4] [Citation(s) in RCA: 158] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Accepted: 03/28/2011] [Indexed: 12/16/2022]
Abstract
Transition metal ions are essential nutrients to all forms of life. Iron, copper, zinc, manganese, cobalt and nickel all have unique chemical and physical properties that make them attractive molecules for use in biological systems. Many of these same properties that allow these metals to provide essential biochemical activities and structural motifs to a multitude of proteins including enzymes and other cellular constituents also lead to a potential for cytotoxicity. Organisms have been required to evolve a number of systems for the efficient uptake, intracellular transport, protein loading and storage of metal ions to ensure that the needs of the cells can be met while minimizing the associated toxic effects. Disruptions in the cellular systems for handling transition metals are observed as a number of diseases ranging from hemochromatosis and anemias to neurodegenerative disorders including Alzheimer's and Parkinson's disease. The yeast Saccharomyces cerevisiae has proved useful as a model organism for the investigation of these processes and many of the genes and biological systems that function in yeast metal homeostasis are conserved throughout eukaryotes to humans. This review focuses on the biological roles of iron, copper, zinc, manganese, nickel and cobalt, the homeostatic mechanisms that function in S. cerevisiae and the human diseases in which these metals have been implicated.
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Affiliation(s)
- Mark R Bleackley
- Department of Biochemistry and Molecular Biology, Centre for Blood Research, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T1Z3, Canada
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22
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Sagasti S, Yruela I, Bernal M, Lujan MA, Frago S, Medina M, Picorel R. Characterization of the recombinant copper chaperone (CCS) from the plant Glycine (G.) max. Metallomics 2011; 3:169-75. [PMID: 21264427 DOI: 10.1039/c0mt00055h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
The goal of the present work was to characterize the recombinant copper chaperone (CCS) from soybean. Very little is known about plant copper chaperones, which makes this study of current interest, and allows for a comparison with the better known homologues from yeast and humans. To obtain sizeable amounts of pure protein suitable for spectroscopic characterization, we cloned and overexpressed the G. max CCS chaperone in E. coli in the presence of 0.5 mM CuSO(4) and 0.5 mM ZnSO(4) in the broth. A pure protein preparation was obtained by using two IMAC steps and pH gradient chromatography. Most of the proteins were obtained as apo-form, devoid of copper atoms. The chaperone showed a high content (i.e., over 40%) of loops, turns and random coil as determined both by circular dichroism and homology modelling. The homology 3-D structural model suggests the protein might fold in three structural protein domains. The 3-D model along with the primary structure and spectroscopic data may suggest that copper atoms occupy the two metal binding sites, MKCEGC and CTC, within the N-terminal domain I and C-terminal domain III, respectively. But only one Zn-binding site was obtained spectroscopically.
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Affiliation(s)
- Sara Sagasti
- Estación Experimental de Aula Dei, Consejo Superior de Investigaciones Científicas, Carretera Montañana 1005, E-50059 Zaragoza, Spain.
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23
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Genome-wide identification of genes that play a role in boron stress response in yeast. Genomics 2011; 97:106-11. [DOI: 10.1016/j.ygeno.2010.10.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2010] [Revised: 10/21/2010] [Accepted: 10/22/2010] [Indexed: 11/21/2022]
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Strategies for stabilizing superoxide dismutase (SOD1), the protein destabilized in the most common form of familial amyotrophic lateral sclerosis. Proc Natl Acad Sci U S A 2010; 107:21394-9. [PMID: 21098299 DOI: 10.1073/pnas.1015463107] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a disorder characterized by the death of both upper and lower motor neurons and by 3- to 5-yr median survival postdiagnosis. The only US Food and Drug Administration-approved drug for the treatment of ALS, Riluzole, has at best, moderate effect on patient survival and quality of life; therefore innovative approaches are needed to combat neurodegenerative disease. Some familial forms of ALS (fALS) have been linked to mutations in the Cu/Zn superoxide dismutase (SOD1). The dominant inheritance of mutant SOD1 and lack of symptoms in knockout mice suggest a "gain of toxic function" as opposed to a loss of function. A prevailing hypothesis for the mechanism of the toxicity of fALS-SOD1 variants, or the gain of toxic function, involves dimer destabilization and dissociation as an early step in SOD1 aggregation. Therefore, stabilizing the SOD1 dimer, thus preventing aggregation, is a potential therapeutic strategy. Here, we report a strategy in which we chemically cross-link the SOD1 dimer using two adjacent cysteine residues on each respective monomer (Cys111). Stabilization, measured as an increase in melting temperature, of ∼20 °C and ∼45 °C was observed for two mutants, G93A and G85R, respectively. This stabilization is the largest for SOD1, and to the best of our knowledge, for any disease-related protein. In addition, chemical cross-linking conferred activity upon G85R, an otherwise inactive mutant. These results demonstrate that targeting these cysteine residues is an important new strategy for development of ALS therapies.
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Kawamata H, Manfredi G. Import, maturation, and function of SOD1 and its copper chaperone CCS in the mitochondrial intermembrane space. Antioxid Redox Signal 2010; 13:1375-84. [PMID: 20367259 PMCID: PMC2962758 DOI: 10.1089/ars.2010.3212] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Cu, Zn, superoxide dismutase (SOD1) is a ubiquitous enzyme localized in multiple cellular compartments, including mitochondria, where it concentrates in the intermembrane space (IMS). Similar to other small IMS proteins, the import and retention of SOD1 in the IMS is linked to its folding and maturation, involving the formation of critical intra- and intermolecular disulfide bonds. Therefore, the cysteine residues of SOD1 play a fundamental role in its IMS localization. IMS import of SOD1 involves its copper chaperone, CCS, whose mitochondrial distribution is regulated by the Mia40/Erv1 disulfide relay system in a redox-dependent manner: CCS promotes SOD1 maturation and retention in the IMS. The function of SOD1 in the IMS is still unknown, but it is plausible that it serves to remove superoxide released from the mitochondrial respiratory chain. Mutations in SOD1 cause familial amyotrophic lateral sclerosis (ALS), whose pathologic features include mitochondrial bioenergetic dysfunction. Mutant SOD1 localization in the IMS is not dictated by oxygen concentration and the Mia40/Erv1 system, but is primarily dependent on aberrant protein folding and aggregation. Mutant SOD1 localization and aggregation in the IMS might cause the mitochondrial abnormalities observed in familial ALS and could play a significant role in disease pathogenesis.
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Affiliation(s)
- Hibiki Kawamata
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, New York 10065, USA
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26
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Ba LA, Doering M, Burkholz T, Jacob C. Metal trafficking: from maintaining the metal homeostasis to future drug design. Metallomics 2009; 1:292-311. [DOI: 10.1039/b904533c] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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27
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Smith A, Rish KR, Lovelace R, Hackney JF, Helston RM. Role for copper in the cellular and regulatory effects of heme-hemopexin. Biometals 2008; 22:421-37. [DOI: 10.1007/s10534-008-9178-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Accepted: 11/04/2008] [Indexed: 10/21/2022]
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Barry AN, Blackburn NJ. A selenocysteine variant of the human copper chaperone for superoxide dismutase. A Se-XAS probe of cluster composition at the domain 3-domain 3 dimer interface. Biochemistry 2008; 47:4916-28. [PMID: 18393442 DOI: 10.1021/bi8001049] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report the semisynthesis of a selenocysteine (Sec) derivative of the human copper chaperone for superoxide dismutase, substituted with Sec at the C-terminal C246 residue. Measurements of hCCS-induced SOD1 activation were used to show that the C-terminal CXC sequence is both necessary and sufficient for EZn-SOD maturation. Therefore, an active CAU variant carrying Sec as the terminal amino acid was prepared by expressed protein ligation of a single selenocysteine amino acid to a 243-CA truncation. This reaction proceeded in high yield and generated the desired 243-CAX (X = C or U) protein with the expected mass. Se-edge XAS of the apoprotein indicated that both Se-S and Se-Se interactions were present in a 0.3:0.7 ratio, indicating an equilibrium between species with either a selenosulfide or a diselenide cross-link. After reduction on immobilized TCEP, the ligated Cys and Sec apoproteins bound up to 2.5 Cu(I) ions per hCCS monomer with both Cu and Se as constituent atoms of the cluster which forms at the domain 3 interface of a hCCS dimer. Merging of XAS data at the Cu and Se K-absorption edges provided additional details of the cluster composition, specifically the fact that both Se atoms occupied bridging positions between two Cu(I) atoms. Further, the requirement for identical Cu-Se bond lengths and Debye-Waller factors at each absorption edge allowed us to rule out simple models for the cluster composition such as a bis-Cys(Sec)-bridged dinuclear cluster and was indicative of a more complex cluster with a nuclearity of >or=3.
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Affiliation(s)
- Amanda N Barry
- Department of Environmental and Biomolecular Systems, OGI School of Science and Engineering, Oregon Health and Sciences University, Beaverton, Oregon 97006-8921, USA
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29
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Proescher JB, Son M, Elliott JL, Culotta VC. Biological effects of CCS in the absence of SOD1 enzyme activation: implications for disease in a mouse model for ALS. Hum Mol Genet 2008; 17:1728-37. [PMID: 18337307 DOI: 10.1093/hmg/ddn063] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The CCS copper chaperone is critical for maturation of Cu, Zn-superoxide dismutase (SOD1) through insertion of the copper co-factor and oxidization of an intra-subunit disulfide. The disulfide helps stabilize the SOD1 polypeptide, which can be particularly important in cases of amyotrophic lateral sclerosis (ALS) linked to misfolding of mutant SOD1. Surprisingly, however, over-expressed CCS was recently shown to greatly accelerate disease in a G93A SOD1 mouse model for ALS. Herein we show that disease in these G93A/CCS mice correlates with incomplete oxidation of the SOD1 disulfide. In the brain and spinal cord, CCS over-expression failed to enhance oxidation of the G93A SOD1 disulfide and if anything, effected some accumulation of disulfide-reduced SOD1. This effect was mirrored in culture with a C244,246S mutant of CCS that has the capacity to interact with SOD1 but can neither insert copper nor oxidize the disulfide. In spite of disulfide effects, there was no evidence for increased SOD1 aggregation. If anything, CCS over-expression prevented SOD1 misfolding in culture as monitored by detergent insolubility. This protection against SOD1 misfolding does not require SOD1 enzyme activation as the same effect was obtained with the C244,246S allele of CCS. In the G93A SOD1 mouse, CCS over-expression was likewise associated with a lack of obvious SOD1 misfolding marked by detergent insolubility. CCS over-expression accelerates SOD1-linked disease without the hallmarks of misfolding and aggregation seen in other mutant SOD1 models. These studies are the first to indicate biological effects of CCS in the absence of SOD1 enzymatic activation.
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Affiliation(s)
- Jody B Proescher
- Division of Toxicological Sciences, Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
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Fujimori T, Yasui H, Hiromura M, Sakurai H. Suppressive effect of orally administered copper(II)-aspirinate (Cu2(asp)4) complex on the generation of reactive oxygen species in the skin of animals subjected to UVA exposure. Exp Dermatol 2007; 16:746-52. [PMID: 17697147 DOI: 10.1111/j.1600-0625.2007.00595.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
As reactive oxygen species (ROS) are involved in the pathogenesis of various diseases, superoxide dismutase (SOD) and its mimetic complexes have been intensively studied. Recently, we found that Cu(2)(aspirinate)(4) (Cu(2)(asp)(4)) has both in vitro and in vivo antioxidative activities. We investigated the suppressive effect of Cu(2)(asp)(4) on ROS generation in the skin of hairless mice that were orally administered Cu(2)(asp)(4) and followed by UVA exposure. The results were compared with those obtained from mice that were orally administered Cu(salicylate)(2) (Cu(sal)(2)) or Cu(acetate)(2), (Cu(ace)(2)) and followed by UVA exposure. After confirming that Cu(2)(asp)(4) suppressed ROS generation in the skin, we measured both SOD activity and metallothionein (MT) and SOD protein levels in the whole proteins extracted from the skin of ICR mice that were orally administered Cu(II) compounds. The Cu(2)Zn(2)-SOD activity was enhanced by the administration of Cu(II) compounds; however, no alterations in the protein levels of MT and SOD were observed. Metallokinetics of the paramagnetic Cu(II) species in the circulating blood of rats, as estimated by electron spin resonance (ESR), revealed that among the Cu(II) compounds, the residence time of the Cu(II) species from Cu(2)(asp)(4) was the longest. On the basis of these results, we conclude that Cu(2)(asp)(4) is an orally potent antioxidative compound that suppresses ROS generation in the skin. The residence time of Cu(II) in the blood and the enhanced SOD activity in the skin following the oral administration of Cu(2)(asp)(4) support this conclusion. Here, we propose that Cu(2)(asp)(4) may be used to protect the skin against ROS generation.
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Affiliation(s)
- Takako Fujimori
- Department of Analytical and Bioinorganic Chemistry, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto, Japan
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Heinicke S, Livstone MS, Lu C, Oughtred R, Kang F, Angiuoli SV, White O, Botstein D, Dolinski K. The Princeton Protein Orthology Database (P-POD): a comparative genomics analysis tool for biologists. PLoS One 2007; 2:e766. [PMID: 17712414 PMCID: PMC1942082 DOI: 10.1371/journal.pone.0000766] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2007] [Accepted: 07/18/2007] [Indexed: 02/07/2023] Open
Abstract
Many biological databases that provide comparative genomics information and tools are now available on the internet. While certainly quite useful, to our knowledge none of the existing databases combine results from multiple comparative genomics methods with manually curated information from the literature. Here we describe the Princeton Protein Orthology Database (P-POD, http://ortholog.princeton.edu), a user-friendly database system that allows users to find and visualize the phylogenetic relationships among predicted orthologs (based on the OrthoMCL method) to a query gene from any of eight eukaryotic organisms, and to see the orthologs in a wider evolutionary context (based on the Jaccard clustering method). In addition to the phylogenetic information, the database contains experimental results manually collected from the literature that can be compared to the computational analyses, as well as links to relevant human disease and gene information via the OMIM, model organism, and sequence databases. Our aim is for the P-POD resource to be extremely useful to typical experimental biologists wanting to learn more about the evolutionary context of their favorite genes. P-POD is based on the commonly used Generic Model Organism Database (GMOD) schema and can be downloaded in its entirety for installation on one's own system. Thus, bioinformaticians and software developers may also find P-POD useful because they can use the P-POD database infrastructure when developing their own comparative genomics resources and database tools.
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Affiliation(s)
- Sven Heinicke
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Michael S. Livstone
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Charles Lu
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Rose Oughtred
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Fan Kang
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Samuel V. Angiuoli
- The Institute for Genomic Research, Rockville, Maryland, United States of America
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, Maryland, United States of America
| | - Owen White
- The Institute for Genomic Research, Rockville, Maryland, United States of America
| | - David Botstein
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Kara Dolinski
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
- * To whom correspondence should be addressed. E-mail:
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Carroll MC, Outten CE, Proescher JB, Rosenfeld L, Watson WH, Whitson LJ, Hart PJ, Jensen LT, Culotta VC. The effects of glutaredoxin and copper activation pathways on the disulfide and stability of Cu,Zn superoxide dismutase. J Biol Chem 2006; 281:28648-56. [PMID: 16880213 PMCID: PMC2757158 DOI: 10.1074/jbc.m600138200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations in Cu,Zn superoxide dismutase (SOD1) can cause amyotrophic lateral sclerosis (ALS) through mechanisms proposed to involve SOD1 misfolding, but the intracellular factors that modulate folding and stability of SOD1 are largely unknown. By using yeast and mammalian expression systems, we demonstrate here that SOD1 stability is governed by post-translational modification factors that target the SOD1 disulfide. Oxidation of the human SOD1 disulfide in vivo was found to involve both the copper chaperone for SOD1 (CCS) and the CCS-independent pathway for copper activation. When both copper pathways were blocked, wild type SOD1 stably accumulated in yeast cells with a reduced disulfide, whereas ALS SOD1 mutants A4V, G93A, and G37R were degraded. We describe here an unprecedented role for the thiol oxidoreductase glutaredoxin in reducing the SOD1 disulfide and destabilizing ALS mutants. Specifically, the major cytosolic glutaredoxin of yeast was seen to reduce the intramolecular disulfide of ALS SOD1 mutant A4V SOD1 in vivo and in vitro. By comparison, glutaredoxin was less reactive toward the disulfide of wild type SOD1. The apo-form of A4V SOD1 was highly reactive with glutaredoxin but not SOD1 containing both copper and zinc. Glutaredoxin therefore preferentially targets the immature form of ALS mutant SOD1 lacking metal co-factors. Overall, these studies implicate a critical balance between cellular reductants such as glutaredoxin and copper activation pathways in controlling the disulfide and stability of SOD1 in vivo.
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Affiliation(s)
- Mark C. Carroll
- Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Caryn E. Outten
- Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Jody B. Proescher
- Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Leah Rosenfeld
- Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Walter H. Watson
- Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Lisa J. Whitson
- Department of Biochemistry and the X-ray Crystallography Core Laboratory, the University of Texas Health Science Center, San Antonio, Texas 78229
| | - P. John Hart
- Department of Biochemistry and the X-ray Crystallography Core Laboratory, the University of Texas Health Science Center, San Antonio, Texas 78229
- Geriatric Research, Education, and Clinical Center, Department of Veterans Affairs, South Texas Veterans Health Care System, the University of Texas Health Science Center, San Antonio, Texas 78229
| | - Laran T. Jensen
- Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Valeria Cizewski Culotta
- Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
- To whom correspondence should be addressed: Dept. of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, 615 N. Wolfe St., Rm. E7626, Baltimore, MD 21205. Tel.: 410-955-3029; Fax: 410-955-0116;
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Zhang F, Zhu H. Intracellular conformational alterations of mutant SOD1 and the implications for fALS-associated SOD1 mutant induced motor neuron cell death. Biochim Biophys Acta Gen Subj 2006; 1760:404-14. [PMID: 16431026 DOI: 10.1016/j.bbagen.2005.11.024] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2005] [Revised: 11/09/2005] [Accepted: 11/28/2005] [Indexed: 10/25/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the selective death of motor neurons. Approximately 10% of ALS cases are familial (fALS) and about 25% of fALS patients inherit autosomal dominant mutations in the gene encoding copper-zinc superoxide dismutase (SOD1). Over 90 different SOD1 mutations have been identified in fALS patients. It has been established that the ALS-linked SOD1 mutations provoke a new toxic function, the nature of which remains unclear. In vitro studies using various biophysical techniques have demonstrated that the SOD1 mutants share a reduced conformational stability. However, conformational alterations of the ALS mutants have not been directly demonstrated in vivo. We employed an SOD1-GFP fusion protein system in this study to monitor the intracellular protein conformation. We demonstrate that the ALS-linked SOD1 mutants adopt different conformations from the wild-type (WT) protein in living cells. Moreover, the conformational alterations of mutant SOD1 render the mutants susceptible to the formation of high-molecular-weight complexes prior to the appearance of detergent-resistant aggregates. Finally, we show that the motor neuron-like cells expressing mutant SOD1 are more susceptible to H2O2 induced cell death compared to the cells expressing WT SOD1. This study provides direct evidence of in vivo conformational differences between WT and mutant SOD1. In addition, the SOD1-GFP system can be exploited in future studies to investigate how conformational alterations of mutant SOD1 lead to protein aggregation and to study the potential toxicity of such aggregates in familial ALS.
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Affiliation(s)
- Fujian Zhang
- Department of Molecular and Cellular Biochemistry, College of Medicine University of Kentucky, 741 South Limestone, Lexington, KY 40536, USA
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Strange RW, Antonyuk SV, Hough MA, Doucette PA, Valentine JS, Hasnain SS. Variable metallation of human superoxide dismutase: atomic resolution crystal structures of Cu-Zn, Zn-Zn and as-isolated wild-type enzymes. J Mol Biol 2005; 356:1152-62. [PMID: 16406071 DOI: 10.1016/j.jmb.2005.11.081] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2005] [Revised: 11/18/2005] [Accepted: 11/23/2005] [Indexed: 11/24/2022]
Abstract
Human Cu-Zn superoxide dismutase (SOD1) protects cells from the effects of oxidative stress. Mutations in SOD1 are linked to the familial form of amyotrophic lateral sclerosis. Several hypotheses for their toxicity involve the mis-metallation of the enzyme. We present atomic-resolution crystal structures and biophysical data for human SOD1 in three metallation states: Zn-Zn, Cu-Zn and as-isolated. These data represent the first atomic-resolution structures for human SOD1, the first structure of a reduced SOD1, and the first structure of a fully Zn-substituted SOD1 enzyme. Recombinantly expressed as-isolated SOD1 contains a mixture of Zn and Cu at the Cu-binding site. The Zn-Zn structure appears to be at least as stable as the correctly (Cu-Zn) metallated enzyme. These data raise the possibility that in a cellular environment with low availability of free copper, Zn-Zn may be the preferred metallation state of SOD1 prior to its interaction with the copper chaperone.
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Affiliation(s)
- Richard W Strange
- Molecular Biophysics Group, CCLRC Daresbury Laboratory, Warrington, Cheshire WA4 4AD, UK
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35
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Jensen LT, Culotta VC. Activation of CuZn Superoxide Dismutases from Caenorhabditis elegans Does Not Require the Copper Chaperone CCS. J Biol Chem 2005; 280:41373-9. [PMID: 16234242 DOI: 10.1074/jbc.m509142200] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Reactive oxygen species are produced as the direct result of aerobic metabolism and can cause damage to DNA, proteins, and lipids. A principal defense against reactive oxygen species involves the superoxide dismutases (SOD) that act to detoxify superoxide anions. Activation of CuZn-SODs in eukaryotic cells occurs post-translationally and is generally dependent on the copper chaperone for SOD1 (CCS), which inserts the catalytic copper cofactor and catalyzes the oxidation of a conserved disulfide bond that is essential for activity. In contrast to other eukaryotes, the nematode Caenorhabditis elegans does not contain an obvious CCS homologue, and we have found that the C. elegans intracellular CuZn-SODs (wSOD-1 and wSOD-5) are not dependent on CCS for activation when expressed in Saccharomyces cerevisiae. CCS-independent activation of CuZn-SODs is not unique to C. elegans; however, this is the first organism identified that appears to exclusively use this alternative pathway. As was found for mammalian SOD1, wSOD-1 exhibits a requirement for reduced glutathione in CCS-independent activation. Unexpectedly, wSOD-1 was inactive even in the presence of CCS when glutathione was depleted. Our investigation of the cysteine residues that form the disulfide bond in wSOD-1 suggests that the ability of wSODs to readily form this disulfide bond may be the key to obtaining high levels of activation through the CCS-independent pathway. Overall, these studies demonstrate that the CuZn-SODs of C. elegans have uniquely evolved to acquire copper without the copper chaperone and this may reflect the lifestyle of this organism.
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Affiliation(s)
- Laran T Jensen
- Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205, USA.
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36
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Abstract
Superoxide dismutases (SOD), a group of metal-containing enzymes, have a vital anti-oxidant role in human health, conferred by their scavenging of one of the reactive oxygen species, superoxide anion. Three types of SODs are known in humans, with the most abundant being cytosolic SOD1, identified by its Cu, Zn-containing prosthetic group. The presence of these metals and the coordination to certain amino acids are essential for function. SODs are among the first line of defense in the detoxification of products resulting from oxidative stress. Here, we describe the importance of SOD function, and the need for coordination with other ROS-scavenging enzymes in this pathway of detoxification. The impact of metal-deficient diets (copper or zinc) or incorrect metal ion incorporation (copper chaperone for SOD) onto nascent SOD, are also examined. Finally, human pathologies associated with either SOD dysfunction or decreased activity are discussed with current progress on the development of novel therapies.
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Affiliation(s)
- Felicity Johnson
- Department of Molecular Biosciences, University of California, 1311 Haring Hall, One Shields Ave, Davis, CA 95616, USA
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37
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Horng YC, Cobine PA, Maxfield AB, Carr HS, Winge DR. Specific Copper Transfer from the Cox17 Metallochaperone to Both Sco1 and Cox11 in the Assembly of Yeast Cytochrome c Oxidase. J Biol Chem 2004; 279:35334-40. [PMID: 15199057 DOI: 10.1074/jbc.m404747200] [Citation(s) in RCA: 211] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The assembly of the copper sites in cytochrome c oxidase involves a series of accessory proteins, including Cox11, Cox17, and Sco1. The two mitochondrial inner membrane proteins Cox11 and Sco1 are thought to be copper donors to the Cu(B) and Cu(A) sites of cytochrome oxidase, respectively, whereas Cox17 is believed to be the copper donor to Sco1 within the intermembrane space. In this report we show Cox17 is a specific copper donor to both Sco1 and Cox11. Using in vitro studies with purified proteins, we demonstrate direct copper transfer from CuCox17 to Sco1 or Cox11. The transfer is specific because no transfer occurs to heterologous proteins, including bovine serum albumin and carbonic anhydrase. In addition, a C57Y mutant of Cox17 fails to transfer copper to Sco1 but is competent for copper transfer to Cox11. The in vitro transfer studies were corroborated by a yeast cytoplasm expression system. Soluble domains of Sco1 and Cox11, lacking the mitochondrial targeting sequence and transmembrane domains, were expressed in the yeast cytoplasm. Metallation of these domains was strictly dependent on the co-expression of Cox17. Thus, Cox17 represents a novel copper chaperone that delivers copper to two proteins.
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Affiliation(s)
- Yih-Chern Horng
- University of Utah Health Sciences Center, Salt Lake City, Utah 84132, USA
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38
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Laliberté J, Whitson LJ, Beaudoin J, Holloway SP, Hart PJ, Labbé S. The Schizosaccharomyces pombe Pccs protein functions in both copper trafficking and metal detoxification pathways. J Biol Chem 2004; 279:28744-55. [PMID: 15107426 DOI: 10.1074/jbc.m403426200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Because copper is both an essential cofactor and a toxic metal, different strategies have evolved to appropriately regulate its homeostasis as a function of changing environmental copper levels. In this report, we describe a metallochaperone-like protein from Schizosaccharomyces pombe that maintains the delicate balance between essentiality and toxicity. This protein, designated Pccs, has four distinct domains. SOD activity assays reveal that the first three domains of Pccs are necessary and sufficient to deliver copper to its target, copper-zinc superoxide dismutase (SOD1). Pccs domain IV, which is absent in Saccharomyces cerevisiae CCS1, contains seventeen cysteine residues, eight pairs of which are in a potential metal coordination arrangement, Cys-Cys. We show that S. cerevisiae ace1Delta mutant cells expressing the full-length Pccs molecule are resistant to copper toxicity. Furthermore, we demonstrate that the Pccs domain IV enhances copper resistance of the ace1Delta cells by an order of magnitude compared with that observed in the same strain expressing a pccs+ I-II-III allele encoding Pccs domains I-III. We consistently found that S. pombe cells disrupted in the pccs+ gene exhibit an increased sensitivity to copper and cadmium. Furthermore, we demonstrate that overexpression of pccs+ is associated with increased copper resistance in fission yeast cells. Taken together, our findings suggest that Pccs activates apo-SOD1 under copper-limiting conditions through the use of its first three domains and protects cells against metal ion toxicity via its fourth domain.
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Affiliation(s)
- Julie Laliberté
- Département de Biochimie, Université de Sherbrooke, 3001 12e Avenue Nord, Sherbrooke, Québec J1H 5N4, Canada
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Carroll MC, Girouard JB, Ulloa JL, Subramaniam JR, Wong PC, Valentine JS, Culotta VC. Mechanisms for activating Cu- and Zn-containing superoxide dismutase in the absence of the CCS Cu chaperone. Proc Natl Acad Sci U S A 2004; 101:5964-9. [PMID: 15069187 PMCID: PMC395906 DOI: 10.1073/pnas.0308298101] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Cu- and Zn-containing superoxide dismutase 1 (SOD1) largely obtains Cu in vivo by means of the action of the Cu chaperone CCS. Yet, in the case of mammalian SOD1, a secondary pathway of activation is apparent. Specifically, when human SOD1 is expressed in either yeast or mammalian cells that are null for CCS, the SOD1 enzyme retains a certain degree of activity. This CCS-independent activity is evident with both wild-type and mutant variants of SOD1 that have been associated with familial amyotrophic lateral sclerosis. We demonstrate here that the CCS-independent activation of mammalian SOD1 involves glutathione, particularly the reduced form, or GSH. A role for glutathione in CCS-independent activation was seen with human SOD1 molecules that were expressed in either yeast cells or immortalized fibroblasts. Compared with mammalian SOD1, the Saccharomyces cerevisiae enzyme cannot obtain Cu without CCS in vivo, and this total dependence on CCS involves the presence of dual prolines near the C terminus of the SOD1 polypeptide. Indeed, the insertion of such prolines into human SOD1 rendered this molecule refractory to CCS-independent activation. The possible implications of multiple pathways for SOD1 activation are discussed in the context of SOD1 evolutionary biology and familial amyotrophic lateral sclerosis.
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Affiliation(s)
- Mark C Carroll
- Department of Environmental Health Sciences, Bloomberg School of Public Health, The Johns Hopkins University, Baltimore, MD 21218, USA
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40
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Prohaska JR, Broderius M, Brokate B. Metallochaperone for Cu,Zn-superoxide dismutase (CCS) protein but not mRNA is higher in organs from copper-deficient mice and rats. Arch Biochem Biophys 2003; 417:227-34. [PMID: 12941305 DOI: 10.1016/s0003-9861(03)00364-3] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Cu,Zn-superoxide dismutase (SOD1) is an abundant metalloenzyme important in scavenging superoxide ions. Cu-deficient rats and mice have lower SOD1 activity and protein, possibly because apo-SOD1 is degraded faster than holo-SOD1. SOD1 interacts with and requires its metallochaperone CCS for donating copper. We produced dietary Cu deficiency in rodents to determine if the reduction in SOD1 was related to the level of its specific metallochaperone CCS. CCS levels determined by immunoblot were 2- to 3-fold higher in liver, heart, kidney, and brain from male Cu-deficient rats and mice under a variety of conditions. CCS was also higher in livers of Cu-deficient dams. Interestingly, CCS levels in brain of Cu-deficient mice were also higher even though SOD1 activity and protein were not altered, suggesting that the rise in CCS is correlated with altered Cu status rather than a direct result of lower SOD1. A DNA probe specific for rat CCS detected a single transcript by Northern blot hybridization with liver RNA. CCS mRNA levels in mouse and rat liver were not altered by dietary treatment. These results suggest a posttranscriptional mechanism for higher CCS protein when Cu is limiting in the cell, perhaps due to slower protein turnover. Elevation in CCS level is one of the most dramatic alterations in Cu binding proteins accompanying Cu deficiency and may be useful to assess Cu status.
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Affiliation(s)
- Joseph R Prohaska
- Department of Biochemistry and Molecular Biology, University of Minnesota Duluth School of Medicine, 1035 University Drive, Duluth, MN 55812, USA.
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41
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Teoh MLT, Walasek PJ, Evans DH. Leporipoxvirus Cu,Zn-superoxide dismutase (SOD) homologs are catalytically inert decoy proteins that bind copper chaperone for SOD. J Biol Chem 2003; 278:33175-84. [PMID: 12773543 DOI: 10.1074/jbc.m300644200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Many Chordopoxviruses encode catalytically inactive homologs of cellular Cu-Zn superoxide dismutase (SOD). The biological function of these proteins is unknown, although the proteins encoded by Leporipoxviruses have been shown to promote a slow decline in the level of superoxide dismutase activity in virus-infected cells. To gain more insights into their function, we have further characterized the enzymatic and biochemical properties of a SOD homolog encoded by Shope fibroma virus. Shope fibroma virus SOD has retained the zinc binding properties of its cellular homolog, but cannot bind copper. Site-directed mutagenesis showed that it requires at least four amino acid substitutions to partially restore copper binding activity, but even these changes still did not restore catalytic activity. Reciprocal co-immunoprecipitation experiments showed that recombinant Shope fibroma virus SOD forms very stable complexes with cellular copper chaperones for SOD and these observations were confirmed using glutathione-S-transferase tagged proteins. Similar viral SOD/chaperone complexes were formed in cells infected with a closely related myxoma virus, where we also noted that some of the SOD antigen co-localizes with mitochondrial markers using confocal fluorescence microscopy. About 2% of the viral SOD was subsequently detected in gradient-purified mitochondria extracted from virus-infected cells. These poxviral SOD homologs do not form stable complexes with cellular Cu,Zn-SOD or affect its concentration. We suggest that Leporipoxvirus SOD homologs are catalytically inert decoy proteins that are designed to interfere in the proper metallation and activation of cellular Cu,Zn-SOD. This reaction might be advantageous for tumorigenic poxviruses, since higher levels of superoxide have been proposed to have anti-apoptotic and tumorigenic activity.
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Affiliation(s)
- Melissa L T Teoh
- Department of Molecular Biology & Genetics, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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42
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Bartnikas TB, Gitlin JD. Mechanisms of biosynthesis of mammalian copper/zinc superoxide dismutase. J Biol Chem 2003; 278:33602-8. [PMID: 12815046 DOI: 10.1074/jbc.m305435200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Copper/zinc superoxide dismutase (SOD1) is an abundant intracellular enzyme with an essential role in antioxidant defense. The activity of SOD1 is dependent upon the presence of a bound copper ion incorporated by the copper chaperone for superoxide dismutase, CCS. To elucidate the cell biological mechanisms of this process, SOD1 synthesis and turnover were examined following 64Cu metabolic labeling of fibroblasts derived from CCS+/+ and CCS-/- embryos. The data indicate that copper is rapidly incorporated into both newly synthesized SOD1 and preformed SOD1 apoprotein, that each process is dependent upon CCS and that once incorporated, copper is unavailable for cellular exchange. The abundance of apoSOD1 is inversely proportional to the intracellular copper content and immunoblot and gel filtration analysis indicate that this apoprotein exists as a homodimer that is distinguishable from SOD1. Despite these distinct differences, the abundance and half-life of SOD1 is equivalent in CCS+/+ and CCS-/- fibroblasts, indicating that neither CCS nor copper incorporation has any essential role in the stability or turnover of SOD1 in vivo. Taken together, these data provide a cell biological model of SOD1 biosynthesis that is consistent with the concept of limited intracellular copper availability and indicate that the metallochaperone CCS is a critical determinant of SOD1 activity in mammalian cells. These kinetic and biochemical findings also provide an important framework for understanding the role of mutant SOD1 in the pathogenesis of familial amyotrophic lateral sclerosis.
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Affiliation(s)
- Thomas B Bartnikas
- Edward Mallinckrodt Department of Pediatrics Washington University School of Medicine, St. Louis, Missouri 63110, USA
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43
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Son M, Cloyd CD, Rothstein JD, Rajendran B, Elliott JL. Aggregate formation in Cu,Zn superoxide dismutase-related proteins. J Biol Chem 2003; 278:14331-6. [PMID: 12551935 DOI: 10.1074/jbc.m211698200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Aggregation of Cu,Zn superoxide dismutase (SOD1) protein is a pathologic hallmark of familial amyotrophic lateral sclerosis linked to mutations in the SOD1 gene, although the structural motifs within mutant SOD1 that are responsible for its aggregation are unknown. Copper chaperone for SOD1 (CCS) and extracellular Cu,Zn superoxide dismutase (SOD3) have some sequence identity with SOD1, particularly in the regions of metal binding, but play no significant role in mutant SOD1-induced disease. We hypothesized that it would be possible to form CCS- or SOD3-positive aggregates by making these molecules resemble mutant SOD1 via the introduction of point mutations in codons homologous to a disease causing G85R SOD1 mutation. Using an in vitro assay system, we found that expression of wild type human CCS or a modified intracellular wild type SOD3 does not result in significant aggregate formation. In contrast, expression of G168R CCS or G146R SOD3 produced aggregates as evidenced by the presence of high molecular weight protein complexes on Western gels or inclusion bodies on immunofluorescence. CCS- and SOD3-positive inclusions appear to be ubiquitinated and localized to aggresomes. These results suggest that proteins sharing structural similarities to mutant SOD1 are also at risk for aggregate formation.
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Affiliation(s)
- Marjatta Son
- Department of Neurology, University of Texas, Southwestern Medical Center, Dallas 75390, USA
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44
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Elam JS, Thomas ST, Holloway SP, Taylor AB, Hart PJ. Copper chaperones. ADVANCES IN PROTEIN CHEMISTRY 2003; 60:151-219. [PMID: 12418178 DOI: 10.1016/s0065-3233(02)60054-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Jennifer Stine Elam
- Center for Biomolecular Structure Analysis, Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229, USA
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Abstract
Copper serves as the essential cofactor for a number of enzymes involved in redox chemistry and virtually all organisms must accumulate trace levels of copper in order to survive. However, this metal can also be toxic and a number of effective methods for sequestering and detoxifying copper prevent the metal from freely circulating inside a cell. Copper metalloenzymes are therefore faced with the challenge of acquiring their precious metal cofactor in the absence of available copper. To overcome this dilemma, all eukaryotic organisms have evolved with a family of intracellular copper binding proteins that help reserve a bioavailable pool of copper for the metalloenzymes, escort the metal to appropriate targets, and directly transfer the copper ion. These proteins have been collectively called "copper chaperones." The identification of such molecules has been made possible through molecular genetic studies in the bakers' yeast Saccharomyces cerevisiae. In this review, we highlight the findings that led to a new paradigm of intracellular trafficking of copper involving the action of copper chaperones. In particular, emphasis will be placed on the ATX1 and CCS copper chaperones that act to deliver copper to the secretory pathway and to Cu/Zn superoxide dismutase in the cytosol, respectively.
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Affiliation(s)
- Lori Sturtz Field
- Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205, USA
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Weder JE, Dillon CT, Hambley TW, Kennedy BJ, Lay PA, Biffin J, Regtop HL, Davies NM. Copper complexes of non-steroidal anti-inflammatory drugs: an opportunity yet to be realized. Coord Chem Rev 2002. [DOI: 10.1016/s0010-8545(02)00086-3] [Citation(s) in RCA: 360] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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47
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Abstract
In the past few years, exciting advances have been made toward understanding how copper is transported into and distributed to cupro-proteins within cells. Recent work has identified high-affinity copper transporters at the plasma membrane in a number of organisms. The elucidation of the three-dimensional structure of copper chaperones and target cupro-proteins has shown that highly specific interactions between homologous domains foster copper transfer between conserved copper ligands, and facilitate a detailed understanding of vectorial copper-transfer reactions. Furthermore, the recent generation of mouse-knockout models, deficient in a high-affinity copper transporter, or in copper chaperones, has demonstrated the importance of copper uptake and targeted distribution in both predicted and fascinating unanticipated ways in growth and development.
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Affiliation(s)
- Sergi Puig
- Department of Biological Chemistry, University of Michigan Medical School, 1301 Catherine Road, Ann Arbor, Michigan 48109-0606, USA
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48
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Sturtz LA, Diekert K, Jensen LT, Lill R, Culotta VC. A fraction of yeast Cu,Zn-superoxide dismutase and its metallochaperone, CCS, localize to the intermembrane space of mitochondria. A physiological role for SOD1 in guarding against mitochondrial oxidative damage. J Biol Chem 2001; 276:38084-9. [PMID: 11500508 DOI: 10.1074/jbc.m105296200] [Citation(s) in RCA: 486] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cu,Zn-superoxide dismutase (SOD1) is an abundant, largely cytosolic enzyme that scavenges superoxide anions. The biological role of SOD1 is somewhat controversial because superoxide is thought to arise largely from the mitochondria where a second SOD (manganese SOD) already resides. Using bakers' yeast as a model, we demonstrate that Cu,Zn-SOD1 helps protect mitochondria from oxidative damage, as sod1Delta mutants show elevated protein carbonyls in this organelle. In accordance with this connection to mitochondria, a fraction of active SOD1 localizes within the intermembrane space (IMS) of mitochondria together with its copper chaperone, CCS. Neither CCS nor SOD1 contains typical N-terminal presequences for mitochondrial uptake; however, the mitochondrial accumulation of SOD1 is strongly influenced by CCS. When CCS synthesis is repressed, mitochondrial SOD1 is of low abundance, and conversely IMS SOD1 is very high when CCS is largely mitochondrial. The mitochondrial form of SOD1 is indeed protective against oxidative damage because yeast cells enriched for IMS SOD1 exhibit prolonged survival in the stationary phase, an established marker of mitochondrial oxidative stress. Cu,Zn-SOD1 in the mitochondria appears important for reactive oxygen physiology and may have critical implications for SOD1 mutations linked to the fatal neurodegenerative disorder, amyotrophic lateral sclerosis.
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Affiliation(s)
- L A Sturtz
- Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205, USA
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49
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Hernández-Saavedra NY, Romero-Geraldo R. Cloning and sequencing the genomic encoding region of copper-zinc superoxide dismutase enzyme from several marine strains of the genus Debaryomyces (Lodder & Kreger-van Rij). Yeast 2001; 18:1227-38. [PMID: 11561290 DOI: 10.1002/yea.768] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Copper-zinc superoxide dismutase (SODC) is a cytosolic enzyme which catalyses the dismutation of the superoxide radical. Due to its physiological importance, the encoding genes have been cloned from several species of higher eukaryotes. However, genes from moulds and yeast have not been studied extensively. In this paper, the encoding region of this gene (sod1) has been cloned from several strains of marine yeast belonging to the genus Debaryomyces (dvv sod1, dvy sod1 and dh sod1-61) through genomic DNA-PCR amplification. Fragments of 480-486 nucleotides were obtained, which contain information for products of 153-156 amino acids with calculated molecular masses of 15.8-16.6 kDa. The deduced amino acid sequence shows that D. vanrijiae enzymes present three additional amino acids not closely related to the active site conformation. In addition, in D. vanrijiae var. vanrijiae (strain 020), one histidine residue is apparently replaced by a proline; the incidence and function of other aromatic or heterocyclic amino acids is discussed. Homology and phylogenetic trees were constructed from amino-acid sequence multi-alignment analyses; the interrelationships among fungi are discussed. The sod-1 sequences reported in this paper were deposited in the public data library of the NCBI under Accession Nos AF301019, AF327449 and AF327448.
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Affiliation(s)
- N Y Hernández-Saavedra
- Centre for Biological Research of the Northwest (CIBNOR), Laboratory of Molecular Genetics, Marine Pathology Unit, PO Box 128, La Paz 23000, Baja California Sur, México.
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50
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Rae TD, Torres AS, Pufahl RA, O'Halloran TV. Mechanism of Cu,Zn-superoxide dismutase activation by the human metallochaperone hCCS. J Biol Chem 2001; 276:5166-76. [PMID: 11018045 DOI: 10.1074/jbc.m008005200] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mechanism for copper loading of the antioxidant enzyme copper, zinc superoxide dismutase (SOD1) by its partner metallochaperone protein is not well understood. Here we show the human copper chaperone for Cu,Zn-SOD1 (hCCS) activates either human or yeast enzymes in vitro by direct protein to protein transfer of the copper cofactor. Interestingly, when denatured with organic solvents, the apo-form of human SOD1 cannot be reactivated by added copper ion alone, suggesting an additional function of hCCS such as facilitation of an active folded state of the enzyme. While hCCS can bind several copper ions, metal binding studies in the presence of excess copper scavengers that mimic the intracellular chelation capacity indicate a limiting stoichiometry of one copper and one zinc per hCCS monomer. This protein is active and unlike the yeast protein, is a homodimer regardless of copper occupancy. Matrix-assisted laser desorption ionization-mass spectrometry and metal binding studies suggest that Cu(I) is bound by residues from the first and third domains and no bound copper is detected for the second domain of hCCS in either the full-length or truncated forms of the protein. Copper-induced conformational changes in the essential C-terminal peptide of hCCS are consistent with a "pivot, insert, and release" mechanism that is similar to one proposed for the well characterized metal handling enzyme, mercuric ion reductase.
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Affiliation(s)
- T D Rae
- Department of Chemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, IL 60208-3113, USA
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