Crystallization and initial crystallographic analysis of the Kelch domain from human Keap1

Li, Xuchu; Zhang, Donna; Hannink, Mark; Beamer, Lesa J.

doi:10.1107/s0907444904024825

Cited by 17 publications

(15 citation statements)

References 14 publications

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“…Since Keap1 functions as a cytosolic inhibitor of Nrf2, and is considered to be the key factor regulating steady-state levels of Nrf2, it is considered as a potential target for therapeutical drug design. In this respect, the recently published initial crystallographic analysis of the Kelch domain of human Keap1 may be encouraging [167].…”

Section: Monofunctional Inducers and Nrf2-are Regulated Gene Expressionmentioning

confidence: 94%

The Nrf2-ARE Signalling Pathway: Promising Drug Target to Combat Oxidative Stress in Neurodegenerative Disorders

Muiswinkel¹,

2005

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A large body of evidence indicates that oxidative stress is a salient pathological feature in many neurodegenerative diseases, including Amyotrophic lateral sclerosis, Alzheimer's disease, and Parkinson's disease. In addition to signs of systemic oxidative stress, at the biochemical and neuropathological level, neuronal degeneration in these disorders has been shown to coincide with several markers of oxidative damage to lipids, nucleic acids, and proteins in affected brain regions. Neuroinflammatory processes, often associated with the induction of free radical generating enzymes and the accumulation of reactive astrocytes and microglial cells, are considered as a major source of oxidative stress. Given the pathogenic impact of oxidative stress and neuroinflammation, therapeutic strategies aimed to blunt these processes are considered an effective way to confer neuroprotection. Recently, the nuclear transcription factor Nrf2, that binds to the antioxidant response element (ARE) in gene promoters, has been reported to constitute a key regulatory factor in the co-ordinate induction of a battery of endogenous cytoprotective genes, including those encoding for both antioxidant- and anti-inflammatory proteins. In the present review, besides discussing recent evidence underscoring the thesis that the Nrf2-ARE signalling pathway is an attractive therapeutic target for neurodegenerative diseases, we advocate the view that chemopreventive agents might be suitable candidates to serve as lead compounds for the development of a new class of neuroprotective drugs.

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Section: Monofunctional Inducers and Nrf2-are Regulated Gene Expressionmentioning

confidence: 94%

The Nrf2-ARE Signalling Pathway: Promising Drug Target to Combat Oxidative Stress in Neurodegenerative Disorders

Muiswinkel¹,

2005

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“…The analysis indicated that Keap1 underwent an isoprostane-mediated loss of ␣-helix content; coincident with an increase in ␤-sheet content and random coil structure. The EPA ox -mediated loss in ␣-helix conformation may be consequence of a change in the BTB domain ␣-helix region (45), because the kelch domain does not contain ␣-helix folding (46). Currently, there is no information concerning the structure of the intervening domain.…”

Section: Volume 282 • Number 4 • January 26 2007mentioning

confidence: 99%

Novel n-3 Fatty Acid Oxidation Products Activate Nrf2 by Destabilizing the Association between Keap1 and Cullin3

Gao

Wang

Sekhar

et al. 2007

Journal of Biological Chemistry

255

165

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Consumption of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) can mitigate the progression of diseases in which oxidative stress represents a common underlying biochemical process. Nrf2-regulated gene expression regulates detoxification of reactive oxygen species. EPA and DHA were subjected to an in vitro free radical oxidation process that models in vivo conditions. Oxidized n-3 fatty acids reacted directly with the negative regulator of Nrf2, Keap1, initiating Keap1 dissociation with Cullin3, thereby inducing Nrf2-directed gene expression. Liquid chromatography-tandem mass spectrometry analyses of oxidized EPA demonstrated the presence of novel cyclopentenone-containing molecules termed J 3 -isoprostanes in vitro and in vivo and were shown to induce Nrf2-directed gene expression. These experiments provide a biochemical basis for the hypothesis that formation of J-ring compounds generated from oxidation of EPA and DHA in vivo can reach concentrations high enough to induce Nrf2-based cellular defense systems.Eicosapentaenoic acid (EPA, C20:5n-3) 5 and docosahexaenoic acid (DHA, C22:6n-3) are two major components of fish oil. Epidemiological studies and randomized controlled trials have demonstrated that n-3 fatty acid supplementation can reduce sudden cardiac death, nonfatal stroke, and decrease progression of arteriosclerosis (1-3). Dietary supplementation with fish oil also shows promise for suppressing progression of neurodegenerative diseases (4), neuropsychiatric disorders (5), human immunodeficiency virus (6), and diseases of the retina (7). Thus, identifying the molecular mechanism(s) responsible for n-3 fatty acid mitigation of these diverse diseases represents an important and intriguing question.Oxidative stress is a common factor in the etiology of the diseases impacted by DHA and EPA (1, 8 -17). These n-3 fatty acids are very susceptible to free radical oxidation, exceeding that of arachidonic acid (AA) (18 -20). Yet, recent studies have shown that EPA and DHA supplementation reduced urinary F 2 -isoprotane levels, a marker for oxidative stress, as well as enhanced cellular antioxidant defense systems (21-24). Although a reduction of F 2 -isoprostane levels can be attributed, in part, to a decrease in membrane AA content (20,25), the relationship between EPA/ DHA oxidation versus EPA/DHA-mediated induction of antioxidant responses is not well understood.Non-enzymatic free-radical peroxidation of AA results in the formation of multiple stereoisomers of prostaglandin H 2 -like bicyclic endoperoxides that can undergo thiol-mediated reduction to form prostaglandin-like compounds termed F 2 -isoprostanes (F 2 -IsoPs) or rearrangement and reduction to form E 2 -IsoPs, D 2 -IsoPs, and isothromboxanes. E 2 /D 2 -IsoPs can then dehydrate to highly reactive A 2 /J 2 -isoprostanes containing cyclopentenone rings. These compounds readily adduct thiol groups on proteins and have been shown to induce Nrf2/ ARE-directed gene expression (26).NF-E2-related factor 2, Nrf2, is a master transcription factor ...

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“…Crystallization and Data Collection-Purification and crystallization of native and selenomethionine (SeMet) Kelch were carried out as previously described (29). Data sets for both the native and SeMet proteins were collected at Ϫ160°C on a Rigaku RU200 rotating anode generator and RAXIS IV detector.…”

Section: Methodsmentioning

confidence: 99%

Crystal Structure of the Kelch Domain of Human Keap1

Zhang

Hannink

et al. 2004

Journal of Biological Chemistry

Self Cite

204

181

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Keap1 is a substrate adaptor protein for an ubiquitin ligase complex that targets the Nrf2 transcription factor for degradation. Keap1 binds Nrf2 through its C-terminal Kelch domain, which contains six copies of the evolutionarily conserved kelch repeat sequence motif. The structure of the Kelch domain from human Keap1 has been determined by x-ray crystallography to a resolution of 1.85 Å. The Kelch domain forms a 6-bladed ␤-propeller structure, with residues at the C terminus forming the first strand in the first blade. Key structural roles have been identified for the highly conserved glycine, tyrosine, and tryptophan residues that define the kelch repeat sequence motif. In addition, we show that substitution of a single amino acid located within a loop that extends out from the bottom of the ␤-propeller structure abolishes binding of Nrf2. The structure of the Kelch domain of Keap1 represents a high quality model for the superfamily of eukaryotic kelch repeat proteins and provides insight into how disease-causing mutations perturb the structural integrity of the Kelch domain.

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Crystallization and initial crystallographic analysis of the Kelch domain from human Keap1

Cited by 17 publications

References 14 publications

The Nrf2-ARE Signalling Pathway: Promising Drug Target to Combat Oxidative Stress in Neurodegenerative Disorders

The Nrf2-ARE Signalling Pathway: Promising Drug Target to Combat Oxidative Stress in Neurodegenerative Disorders

Novel n-3 Fatty Acid Oxidation Products Activate Nrf2 by Destabilizing the Association between Keap1 and Cullin3

Crystal Structure of the Kelch Domain of Human Keap1

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