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della Valle E, Marracino P, Pakhomova O, Liberti M, Apollonio F. Nanosecond pulsed electric signals can affect electrostatic environment of proteins below the threshold of conformational effects: The case study of SOD1 with a molecular simulation study. PLoS One 2019; 14:e0221685. [PMID: 31454403 PMCID: PMC6711501 DOI: 10.1371/journal.pone.0221685] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 08/13/2019] [Indexed: 12/19/2022] Open
Abstract
Electric fields can be a powerful tool to interact with enzymes or proteins, with an intriguing perspective to allow protein manipulation. Recently, researchers have focused the interest on intracellular enzyme modifications triggered by the application of nanosecond pulsed electric fields. These findings were also supported by theoretical predictions from molecular dynamics simulations focussing on significant variations in protein secondary structures. In this work, a theoretical study utilizing molecular dynamics simulations is proposed to explore effects of electric fields of high intensity and very short nanosecond duration applied to the superoxide dismutase (Cu/Zn-SOD or SOD-1), an important enzyme involved in the cellular antioxidant defence mechanism. The effects of 100-nanosecond pulsed electric fields, with intensities ranging from 108 to 7x108 V/m, on a single SOD1 enzyme are presented. We demonstrated that the lowest intensity of 108 V/m, although not inducing structural changes, can produce electrostatic modifications on the reaction centre of the enzyme, as apparent from the dipolar response and the electric field distribution of the protein active site. Electric pulses above 5x108 V/m produced a fast transition between the folded and a partially denatured state, as inferred by the secondary structures analysis. Finally, for the highest field intensity used (7x108 V/m), a not reversible transition toward an unfolded state was observed.
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Affiliation(s)
- Elena della Valle
- BioElectronic Vision Lab, University of Michigan, Ann Arbor, Michigan, United States of America
| | | | - Olga Pakhomova
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, Virginia, United States of America
| | - Micaela Liberti
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, Rome, Italy
| | - Francesca Apollonio
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, Rome, Italy
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Wan ZH, Zhang YJ, Chen L, Guo YL, Li GH, Wu D, Wang Y. G protein-coupled receptor kinase 2 inhibition improves erectile function through amelioration of endothelial dysfunction and oxidative stress in a rat model of type 2 diabetes. Asian J Androl 2019; 21:74-79. [PMID: 30226217 PMCID: PMC6337949 DOI: 10.4103/aja.aja_69_18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 07/10/2018] [Indexed: 12/12/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) is a common cause of erectile dysfunction (ED). It has been demonstrated that G protein-coupled receptor kinase 2 (GRK2) overexpression contributes to diabetic endothelial dysfunction and oxidative stress, which also underlies ED in T2DM. We hypothesized that GRK2 overexpressed and attenuated endothelial function of the cavernosal tissue in a rat model of T2DM. T2DM rats were established by feeding with a high-fat diet (HFD) for 2 weeks and then administering two intraperitoneal (IP) injections of a low dose of streptozotocin (STZ), followed by continuous feeding with a HFD for 6 weeks. GRK2 was inhibited by IP injection of paroxetine, a selective GRK2 inhibitor, after STZ injection. Insulin challenge tests, intracavernous pressure (ICP), GRK2 expression, the protein kinase B (Akt)/endothelial nitric oxide synthase (eNOS) pathway, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit gp91 phox , nitric oxide (NO), reactive oxygen species (ROS) production, and apoptosis in cavernosal tissue were examined. Less response to insulin injection was observed in T2DM rats 2 weeks after HFD. Markedly increased GRK2 expression, along with impaired Akt/eNOS pathway, reduced NO production, increased gp91 phox expression and ROS generation, increased apoptosis and impaired erectile function were found in T2DM rats. Inhibition of GRK2 with paroxetine ameliorated Akt/eNOS signaling, restored NO production, downregulated NADPH oxidase, subsequently inhibited ROS generation and apoptosis, and ultimately preserved erectile function. These results indicated that GRK2 upregulation may be an important mechanism underlying T2DM ED, and GRK2 inhibition may be a potential therapeutic strategy for T2DM ED.
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Affiliation(s)
- Zhi-Hua Wan
- Department of Urology, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430014, China
| | - Yuan-Jie Zhang
- Department of Urology, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430014, China
| | - Lin Chen
- Department of Urology, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430014, China
| | - Yong-Lian Guo
- Department of Urology, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430014, China
| | - Guo-Hao Li
- Department of Urology, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430014, China
| | - Ding Wu
- Department of Urology, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430014, China
| | - Yong Wang
- Department of Urology, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430014, China
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Obrosov A, Shevalye H, Coppey LJ, Yorek MA. Effect of tempol on peripheral neuropathy in diet-induced obese and high-fat fed/low-dose streptozotocin-treated C57Bl6/J mice. Free Radic Res 2017; 51:360-367. [PMID: 28376643 DOI: 10.1080/10715762.2017.1315767] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
In this study, we sought to determine the efficacy of tempol on multiple neuropathic endpoints in a diet-induced obese mouse, a model of pre-diabetes, and a high-fat fed low-dose streptozotocin treated mouse, a model of type 2 diabetes. Tempol (4-hydroxy-2,2,6,6-tetramethylpiperdine -1-oxyl) is a low molecular weight, water soluble, membrane permeable, and metal-independent superoxide dismutase mimetic that has been widely used in cellular studies for the removal of intracellular and extracellular superoxide. This in vivo study was designed to be an early intervention. Fourteen weeks post-high-fat diet (6 weeks post-hyperglycemia) control, obese, and diabetic mice were divided into no treatment and treatment groups. The treated mice received tempol by gavage (150 mg/kg in water), while the untreated mice received vehicle. The diet-induced obese and the diabetic mice were maintained on the high-fat diet for the duration of the study, while the control group was maintained on the standard diet. Obesity and diabetes caused slowing of motor and sensory nerve conduction, reduction in intraepidermal nerve fiber density, thermal hypoalgesia, and mechanical allodynia. Treatment with tempol partially or completely protected obese and diabetic mice from these deficits. These studies suggest that tempol or other effective scavengers of reactive oxygen species may be a viable option for treating neural complications associated with obesity or type 2 diabetes.
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Affiliation(s)
- Alexander Obrosov
- a Department of Internal Medicine , University of Iowa , Iowa City , IA , USA
| | - Hanna Shevalye
- a Department of Internal Medicine , University of Iowa , Iowa City , IA , USA
| | - Lawrence J Coppey
- a Department of Internal Medicine , University of Iowa , Iowa City , IA , USA
| | - Mark A Yorek
- a Department of Internal Medicine , University of Iowa , Iowa City , IA , USA.,b Department of Veterans Affairs Iowa City Health Care System , Iowa City , IA , USA.,c Fraternal Order of Eagles Diabetes Research Center, University of Iowa , Iowa City , IA , USA
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Kucukdurmaz F, Kucukgergin C, Akman T, Salabas E, Armagan A, Seckin S, Kadıoglu A. Duration of priapism is associated with increased corporal oxidative stress and antioxidant enzymes in a rat model. Andrologia 2015. [DOI: 10.1111/and.12455] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Affiliation(s)
- F. Kucukdurmaz
- Istanbul University; Istanbul Medical Faculty; Department of Urology; Istanbul Turkey
| | - C. Kucukgergin
- Istanbul University Istanbul Medical Faculty; Department of Biochemistry; Istanbul Turkey
| | - T. Akman
- Bezmialem Vakif University; Faculty of Medicine; Department of Urology; Istanbul Turkey
| | - E. Salabas
- Istanbul University; Istanbul Medical Faculty; Department of Urology; Istanbul Turkey
| | - A. Armagan
- Bezmialem Vakif University; Faculty of Medicine; Department of Urology; Istanbul Turkey
| | - S. Seckin
- Istanbul University Istanbul Medical Faculty; Department of Biochemistry; Istanbul Turkey
| | - A. Kadıoglu
- Istanbul University; Istanbul Medical Faculty; Department of Urology; Istanbul Turkey
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Hsu CH, Lin CL, Wang SE, Sheu SJ, Chien CT, Wu CH. Oral treatment with herbal formula B401 alleviates penile toxicity in aging mice with manganism. Clin Interv Aging 2015; 10:907-18. [PMID: 26064043 PMCID: PMC4455845 DOI: 10.2147/cia.s82026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The present study aims to elucidate the roles of nitric oxide synthase activity, oxidative stress, inflammation, and apoptosis in penile toxicity of aging mice associated with excess manganese (Mn) treatment and to investigate the effect of oral treatment with the herbal formula B401 in this respect. ICR strain mice were divided into two groups: the vehicle (sham group) and the B401 (50 mg/kg) group. The mice were orally treated for 5 days; then a high single dose of MnCl2 (100 mg/kg) was given by intraperitoneal injection to the mice. One day after MnCl2 treatment, corpora cavernosal tissues of both Mn-treated mice and their controls were simultaneously sampled to examine their immunohistochemical staining and Western blot analysis. Nitric oxide (NO) production, levels of neuronal nitric oxide synthase (nNOS) and endothelial nitric oxide synthase (eNOS), expression levels of factors governing angiogenesis (vascular endothelial growth factor), oxidative stress (catalase, superoxide dismutase 2,4-hydroxynonenal), inflammation (tumor necrosis factor alpha), apoptosis (B-cell lymphoma 2 [Bcl-2], Bcl-2-associated X protein [Bax], cleaved poly(adenosine diphosphate-ribose) polymerase [c-PARP], cytochrome C, caspase-12, and caspase-3) were evaluated in penile corpus cavernosum of the mice. We found that penile toxicity in the mice was enhanced under excess Mn treatment through reduction of NOS activity and increase in oxidative stress, inflammation, and apoptosis in the penile cavernous tissue. Furthermore, the penile toxicity in mice with manganism was alleviated by oral B401 treatment through enhancement of both nitric oxide synthesis and angiogenesis, with simultaneous reduction of oxidative stress, inflammation, and apoptosis in penile corpus cavernosum. We suggest that the herbal formula B401 may serve as a potential dietotherapeutic supplement for penile toxicity or dysfunction in aging males.
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Affiliation(s)
- Chih-Hsiang Hsu
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Ching-Lung Lin
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Sheue-Er Wang
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | | | - Chiang-Ting Chien
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Chung-Hsin Wu
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
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Soni SD, Song W, West JL, Khera M. Nitric oxide-releasing polymeric microspheres improve diabetes-related erectile dysfunction. J Sex Med 2013; 10:1915-25. [PMID: 23751157 DOI: 10.1111/jsm.12216] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
INTRODUCTION We have used a long-acting nitric oxide (NO)-releasing polymer to develop injectable biodegradable microspheres capable of localized NO release over prolonged periods of time. AIM The aim of this study was to evaluate the therapeutic potential of these microspheres for diabetes-related erectile dysfunction (ED) in the rat model. METHODS NO-releasing microspheres were incubated in physiologic buffer, and in vitro NO release was measured using a Griess assay. To ensure no migration, microspheres were fluorescently tagged and injected into the corpus cavernosum of adult rats, and fluorescent imaging was performed weekly for 4 weeks, at which point rats were sacrificed. To assess physiologic efficacy, diabetes was induced in 40 rats using streptozotocin (STZ), whereas 10 rats were kept as age-matched controls. Diabetic rats were divided into four groups: no treatment, sildenafil, NO-releasing microspheres, and combination therapy. For each rat, the cavernosal nerve (CN) was stimulated at various voltages, and intracavernosal pressure (ICP) and mean arterial pressure (MAP) were measured via corpus cavernosum and carotid artery catheterization, respectively. Long-term efficacy was determined by injecting diabetic rats with microspheres and measuring erectile response at predetermined intervals for up to 5 weeks. MAIN OUTCOME MEASURES Erectile response was determined via calculation of mean peak ICP/MAP and area under curve (AUC) for each experimental group. RESULTS Under physiologic conditions in vitro, microspheres continued NO release for up to 4 weeks. Fluorescent imaging revealed no detectable signal in tissues besides cavernosal tissue at 4 weeks postinjection. Upon CN stimulation, peak ICP/MAP ratio and AUC of diabetic rats improved significantly (P < 0.05) in microsphere and combination therapy groups compared with no treatment and sildenafil groups. In long-term efficacy studies, microspheres augmented the effect of sildenafil for 3 weeks following injection (P < 0.05). CONCLUSIONS NO-releasing microspheres significantly improved erectile response in diabetic rats for 3 weeks and hence offer a promising approach to ED therapy, either as monotherapy or combination therapy.
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Affiliation(s)
- Samit D Soni
- Scott Department of Urology, Baylor College of Medicine, Houston, TX 77030, USA.
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Chen Y, Li XX, Lin HC, Qiu XF, Gao J, Dai YT, Wang R. The effects of long-term administration of tadalafil on STZ-induced diabetic rats with erectile dysfunction via a local antioxidative mechanism. Asian J Androl 2012; 14:616-20. [PMID: 22504870 DOI: 10.1038/aja.2012.22] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Type 5 phosphodiesterase inhibitors (PDE5Is) are well known being effective via the nitric oxide and cyclic guanosine monophosphate (NO-cGMP) pathway and are widely used in the treatment of diabetic erectile dysfunction (ED). However, it is unclear whether other pathways may be involved in the treatment of diabetic ED with PDE5Is. The purpose of this study was to clarify the role of antioxidants in diabetic ED treatment through the long-term administration of PDE5Is. Three groups of Sprague-Dawley rats were utilized: Group N, the normal control; Group D, streptozotocin (STZ)-induced diabetic rats as a control; and Group D+T, STZ-induced diabetic rats who received oral administration of tadalafil for 8 weeks. Erectile function was assessed by intracavernous pressure (ICP) and mean arterial pressure (MAP) during electrical stimulation of the cavernous nerve before euthanasia. The levels of malondialdehyde (MDA), superoxide dismutase (SOD) and mitochondrial membrane potential (MMP) of cavernous tissue were assessed by biochemical analysis. The morphology of mitochondria was observed by electron microscopy. The ICP/MAP ratio was higher in Group D+T than in Group D (P<0.05). The levels of MDA decreased and the activities of SOD increased in Group D+T in comparison with Group D (P<0.05). The mitochondrial membrane potential level of cavernous tissue in diabetic rats was partially recovered by tadalafil treatment for 8 weeks. The morphology changes of mitochondria were also remarkably ameliorated in Group D+T. Collectively, the long-term administration of tadalafil in diabetic rats partially reduced oxidative stress lesions of the penis via a local antioxidative stress pathway. Long-term dosages of tadalafil given once daily beginning soon after the onset of diabetes may aid in preventing rats from developing diabetic ED.
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Affiliation(s)
- Yun Chen
- Department of Urology, the Affiliated Drum Tower Hospital, Nanjing University Medical School, Nanjing 210008, China
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Zhang W, Wang Y, Yang Z, Qiu J, Ma J, Zhao Z, Bao T. Antioxidant treatment with quercetin ameliorates erectile dysfunction in streptozotocin-induced diabetic rats. J Biosci Bioeng 2011; 112:215-8. [PMID: 21664865 DOI: 10.1016/j.jbiosc.2011.05.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Revised: 05/12/2011] [Accepted: 05/23/2011] [Indexed: 12/18/2022]
Abstract
Oxidative stress is demonstrated to be involved in the pathophysiological mechanism of erectile dysfunction (ED). Quercetin, a potent bioflavonoid, has been reported to have the antioxidant role. In the present study, we examined the effect of quercetin on ED and oxidative stress in streptozotocin (STZ)-induced diabetic rats. Diabetes was induced in Sprague-Dawley rats with a single intravenous injection of STZ. The diabetic rats were then randomized to diabetic group and quercetin therapy groups which were treated with quercetin at different doses of 5, 20 and 50mg/kg per day respectively. At the end of the 8th week, erectile function was assessed by measuring the rise in intracavernous pressure (ICP) following cavernous nerve electrostimulation. Superoxide dismutase (SOD) activity, thiobarbituric acid-reacting substance (TBARS) and nitrite and nitrate (NOx) levels were measured in cavernosum tissue. Endothelial NO synthase (eNOS) expression was determined using Western blot method. ICP in diabetic rats was significantly decreased than that in controls. After treatment with quercetin at the doses of 20 and 50mg/kg, ICP was significantly increased compared to that in untreated diabetic rats. Decreased levels of SOD activity, NOx and eNOS expression, as well as elevated levels of TBARS were found in diabetic group compared with control group. Treatment with 20 and 50mg/kg quercetin improved SOD activity, NOx and TBARS levels in corpus cavernosum of diabetic rats. Decreased expression of eNOS in diabetic rats was only ameliorated by 50mg/kg quercetin treatment. Quercetin could ameliorate ED in diabetic rats by inhibiting oxidative stress.
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Affiliation(s)
- Wei Zhang
- Department of Urology, Tangdu Hospital, Fourth Military Medical University, 1 Xinsi Road, Xian, Shanxi, P. R. China
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Kanika ND, Melman A, Davies KP. Experimental priapism is associated with increased oxidative stress and activation of protein degradation pathways in corporal tissue. Int J Impot Res 2010; 22:363-73. [PMID: 21085184 PMCID: PMC3058910 DOI: 10.1038/ijir.2010.27] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Priapism is a debilitating disease for which there is at present no clinically accepted pharmacologic intervention. It has been estimated that priapism lasting more than 24 hours in patients is associated with a 44–90% rate of erectile dysfunction (ED). In this investigation we determined in two animal models of priapism (opiorpin-induced priapism in the rat and priapism in a mouse model of sickle cell disease) if there is evidence for an increase in markers of oxidative stress in corporal tissue. In both animal models we demonstrate that priapism results in increased levels of lipid peroxidation, glutathione S-transferase activity, and oxidatively damaged proteins in corporal tissue. Using Western blot analysis we demonstrated there is up regulation of the ubiquitination ligase proteins, Nedd-4 and Mdm-2, and the lysososomal autophage protein, LC3. The anti-apoptotic protein, Bcl-2, was also up regulated. Overall, we demonstrate that priapism is associated with increased oxidative stress in corporal tissue and the activation of protein degradation pathways. Since oxidative stress is known to mediate the development of ED resulting from several etiologies (for example ED resulting from diabetes and aging) we suggest that damage to erectile tissue resulting from priapism might be prevented by treatments targeting oxidative stress.
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Affiliation(s)
- N D Kanika
- Department of Urology, Institute of Smooth Muscle Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Perry J, Shin D, Getzoff E, Tainer J. The structural biochemistry of the superoxide dismutases. BIOCHIMICA ET BIOPHYSICA ACTA 2010; 1804:245-62. [PMID: 19914407 PMCID: PMC3098211 DOI: 10.1016/j.bbapap.2009.11.004] [Citation(s) in RCA: 322] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2009] [Revised: 11/04/2009] [Accepted: 11/05/2009] [Indexed: 01/11/2023]
Abstract
The discovery of superoxide dismutases (SODs), which convert superoxide radicals to molecular oxygen and hydrogen peroxide, has been termed the most important discovery of modern biology never to win a Nobel Prize. Here, we review the reasons this discovery has been underappreciated, as well as discuss the robust results supporting its premier biological importance and utility for current research. We highlight our understanding of SOD function gained through structural biology analyses, which reveal important hydrogen-bonding schemes and metal-binding motifs. These structural features create remarkable enzymes that promote catalysis at faster than diffusion-limited rates by using electrostatic guidance. These architectures additionally alter the redox potential of the active site metal center to a range suitable for the superoxide disproportionation reaction and protect against inhibition of catalysis by molecules such as phosphate. SOD structures may also control their enzymatic activity through product inhibition; manipulation of these product inhibition levels has the potential to generate therapeutic forms of SOD. Markedly, structural destabilization of the SOD architecture can lead to disease, as mutations in Cu,ZnSOD may result in familial amyotrophic lateral sclerosis, a relatively common, rapidly progressing and fatal neurodegenerative disorder. We describe our current understanding of how these Cu,ZnSOD mutations may lead to aggregation/fibril formation, as a detailed understanding of these mechanisms provides new avenues for the development of therapeutics against this so far untreatable neurodegenerative pathology.
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Affiliation(s)
- J.J.P. Perry
- Skaggs Institute for Chemical Biology and Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
- The School of Biotechnology, Amrita University, Kollam, Kerala 690525, India
| | - D.S. Shin
- Skaggs Institute for Chemical Biology and Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - E.D. Getzoff
- Skaggs Institute for Chemical Biology and Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - J.A. Tainer
- Skaggs Institute for Chemical Biology and Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
- Life Sciences Division, Department of Molecular Biology, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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