Medicine and Health Sciences | Open Access Articles

Local Flexibility In Molecular Function Paradigm, Jag Bhalla, Geoffrey B. Storchan, Caitlin M. Maccarthy, Vladimir N. Uversky, Olga Tcherkasskaya

Molecular Medicine Faculty Publications

It is generally accepted that the functional activity of biological macromolecules requires tightly packed three-dimensional structures. Recent theoretical and experimental evidence indicates, however, the importance of molecular flexibility for the proper functioning of some proteins. We examined high resolution structures of proteins in various functional categories with respect to the secondary structure assessment. The latter was considered as a characteristic of the inherent flexibility of a polypeptide chain. We found that the proteins in functionally competent conformational states might be comprised of 20–70% flexible residues. For instance, proteins involved in gene regulation, e.g. transcription factors, are on average largely disordered …

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Structural And Functional Adaptations To Extreme Temperatures In Psychrophilic, Mesophilic, And Thermophilic Dna Ligases, Daphné Georlette, Benjamin Damien, Vinciane Blaise, Eric Depiereux, Vladimir N. Uversky, Charles Gerday, Georges Feller

Molecular Medicine Faculty Publications

Psychrophiles, host of permanently cold habitats, display metabolic fluxes comparable to those exhibited by mesophilic organisms at moderate temperatures. These organisms have evolved by producing, among other peculiarities, cold-active enzymes that have the properties to cope with the reduction of chemical reaction rates induced by low temperatures. The emerging picture suggests that these enzymes display a high catalytic efficiency at low temperatures through an improved flexibility of the structural components involved in the catalytic cycle, whereas other protein regions, if not implicated in catalysis, may be even more rigid than their mesophilic counterparts. In return, the increased flexibility leads to …

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Cofactor Binding Modulates The Conformational Stabilities And Unfolding Patterns Of Nad+-Dependent Dna Ligases From Escherichia Coli And Thermus Scotoductus, Daphné Georlette, Vinciane Blaise, Christophe Dohmen, Fabrice Bouillenne, Benjamin Damien, Eric Depiereux, Charles Gerday, Vladimir N. Uversky, Georges Feller

Molecular Medicine Faculty Publications

DNA ligases are important enzymes required for cellular processes such as DNA replication, recombination, and repair. NAD⁺-dependent DNA ligases are essentially restricted to eubacteria, thus constituting an attractive target in the development of novel antibiotics. Although such a project might involve the systematic testing of a vast number of chemical compounds, it can essentially gain from the preliminary deciphering of the conformational stability and structural perturbations associated with the formation of the catalytically active adenylated enzyme. We have, therefore, investigated the adenylation-induced conformational changes in the mesophilic Escherichia coli and thermophilic Thermus scotoductus NAD⁺-DNA ligases, and …

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The Herbicide Paraquat Causes Up-Regulation And Aggregation Of Α-Synuclein In Mice: Paraquat And Α-Synuclein, Amy B. Manning-Bog, Alison L. Mccormack, Jie Li, Vladimir N. Uversky, Anthony L. Fink, Donato A. Di Monte

Molecular Medicine Faculty Publications

α-Synuclein-containing aggregates represent a feature of a variety of neurodegenerative disorders, including Parkinson's disease (PD). However, mechanisms that promote intraneuronal α-synuclein assembly remain poorly understood. Because pesticides, particularly the herbicide paraquat, have been suggested to play a role as PD risk factors, the hypothesis that interactions between α-synuclein and these environmental agents may contribute to aggregate formation was tested in this study. Paraquat markedly accelerated the in vitro rate of α-synuclein fibril formation in a dose-dependent fashion. When mice were exposed to the herbicide, brain levels of α-synuclein were significantly increased. This up-regulation followed a consistent pattern, with higher α-synuclein …

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Elucidation Of The Molecular Mechanism During The Early Events In Immunoglobulin Light Chain Amyloid Fibrillation: Evidence For An Off-Pathway Oligomer At Acidic Ph, Pierre O. Souillac, Vladimir N. Uversky, Ian S. Millett, Ritu Khurana, Sebastian Doniach, Anthony L. Fink

Molecular Medicine Faculty Publications

Light chain amyloidosis involves the systemic pathologic deposition of monoclonal light chain variable domains of immunoglobulins as insoluble fibrils. The variable domain LEN was obtained from a patient who had no overt amyloidosis; however, LEN forms fibrils in vitro, under mildly destabilizing conditions. The in vitro kinetics of fibrillation were investigated using a wide variety of probes. The rate of fibril formation was highly dependent on the initial protein concentration. In contrast to most amyloid systems, the kinetics became slower with increasing LEN concentrations. At high protein concentrations a significant lag in time was observed between the conformational changes …

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Biophysical Properties Of The Synucleins And Their Propensities To Fibrillate: Inhibition Of Α-Synuclein Assembly By Β- And Γ-Synucleins, Vladimir N. Uversky, Jie Li, Pierre O. Souillac, Ian S. Millett, Sebastian Doniach, Ross Jakes, Michael Goedert, Anthony L. Fink

Molecular Medicine Faculty Publications

The pathological hallmark of Parkinson's disease is the presence of intracellular inclusions, Lewy bodies, and Lewy neurites, in the dopaminergic neurons of the substantia nigra and several other brain regions. Filamentous α-synuclein is the major component of these deposits and its aggregation is believed to play an important role in Parkinson's disease and several other neurodegenerative diseases. Two homologous proteins, β- and γ-synucleins, are also abundant in the brain. The synucleins are natively unfolded proteins. β-Synuclein, which lacks 11 central hydrophobic residues compared with its homologs, exhibited the properties of a random coil, whereas α- and γ-synucleins were slightly more …

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Evidence For A Partially Folded Intermediate In Α-Synuclein Fibril Formation, Vladimir N. Uversky, Jie Li, Anthony L. Fink

Molecular Medicine Faculty Publications

Intracellular proteinaceous aggregates (Lewy bodies and Lewy neurites) of α-synuclein are hallmarks of neurodegenerative diseases such as Parkinson's disease, dementia with Lewy bodies, and multiple systemic atrophy. However, the molecular mechanisms underlying α-synuclein aggregation into such filamentous inclusions remain unknown. An intriguing aspect of this problem is that α-synuclein is a natively unfolded protein, with little or no ordered structure under physiological conditions. This raises the question of how an essentially disordered protein is transformed into highly organized fibrils. In the search for an answer to this question, we have investigated the effects of pH and temperature on the structural …

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Is Congo Red An Amyloid-Specific Dye?, Ritu Khurana, Vladimir N. Uversky, Liza Nielsen, Anthony L. Fink

Molecular Medicine Faculty Publications

Congo red (CR) binding, monitored by characteristic yellow-green birefringence under crossed polarization has been used as a diagnostic test for the presence of amyloid in tissue sections for several decades. This assay is also widely used for the characterization of in vitro amyloid fibrils. In order to probe the structural specificity of Congo red binding to amyloid fibrils we have used an induced circular dichroism (CD) assay. Amyloid fibrils from insulin and the variable domain of Ig light chain demonstrate induced CD spectra upon binding to Congo red. Surprisingly, the native conformations of insulin and Ig light chain also induced …

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Metal-Triggered Structural Transformations, Aggregation, And Fibrillation Of Human Α-Synuclein: A Possible Molecular Link Between Parkinson′S Disease And Heavy Metal Exposure, Vladimir N. Uversky, Jie Li, Anthony L. Fink

Molecular Medicine Faculty Publications

Parkinson's disease involves the aggregation of α-synuclein to form fibrils, which are the major constituent of intracellular protein inclusions (Lewy bodies and Lewy neurites) in dopaminergic neurons of the substantia nigra. Occupational exposure to specific metals, especially manganese, copper, lead, iron, mercury, zinc, aluminum, appears to be a risk factor for Parkinson's disease based on epidemiological studies. Elevated levels of several of these metals have also been reported in the substantia nigra of Parkinson's disease subjects. We examined the effect of various metals on the kinetics of fibrillation of recombinant α-synuclein and in inducing conformational changes, as monitored by biophysical …

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Stabilization Of Partially Folded Conformation During Α-Synuclein Oligomerization In Both Purified And Cytosolic Preparations, Vladimir N. Uversky, He-Jin Lee, Jie Li, Anthony L. Fink, Seung-Jae Lee

Molecular Medicine Faculty Publications

Aggregation of α-synuclein is tightly associated with many neurodegenerative diseases, such as Parkinson's disease, dementia with Lewy body, Lewy body variant of Alzheimer's disease, multiple system atrophy, and Hallervorden-Spatz disease, implicating a crucial role of aggregated forms of α-synuclein in the pathogenesis. Here, we examined the effect of elevated temperature on the oligomerization and structural changes of α-synuclein in the early stage of aggregation and show that self-assembly is crucial for the stabilization of a partially folded conformation. The efficiency of α-synuclein oligomerization increased proportional to the temperature increase, both in purified form and in crude cytosolic preparation. This oligomerization …

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Cannabinoids And The Immune System, Thomas W. Klein, Catherine A. Newton, Herman Friedman

Molecular Medicine Faculty Publications

The effect of cannabimimetic agents on the function of immune cells such as T and B lymphocytes, natural killer cells and macrophages has been extensively studied over the past several decades using human and animal paradigms involving whole animal models as well as tissue culture systems. From this work, it can be concluded that these drugs have subtle yet complex effects on immune cell function and that some of the drug activity is mediated by cannabinoid receptors expressed on the various immune cell subtypes. However, the overall role of the cannabinoid system of receptors and ligands in human health and …

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Full-Text Articles in Medicine and Health Sciences

Local Flexibility In Molecular Function Paradigm, Jag Bhalla, Geoffrey B. Storchan, Caitlin M. Maccarthy, Vladimir N. Uversky, Olga Tcherkasskaya

Molecular Medicine Faculty Publications

Structural And Functional Adaptations To Extreme Temperatures In Psychrophilic, Mesophilic, And Thermophilic Dna Ligases, Daphné Georlette, Benjamin Damien, Vinciane Blaise, Eric Depiereux, Vladimir N. Uversky, Charles Gerday, Georges Feller

Molecular Medicine Faculty Publications

Molecular Medicine Faculty Publications

The Herbicide Paraquat Causes Up-Regulation And Aggregation Of Α-Synuclein In Mice: Paraquat And Α-Synuclein, Amy B. Manning-Bog, Alison L. Mccormack, Jie Li, Vladimir N. Uversky, Anthony L. Fink, Donato A. Di Monte

Molecular Medicine Faculty Publications

Elucidation Of The Molecular Mechanism During The Early Events In Immunoglobulin Light Chain Amyloid Fibrillation: Evidence For An Off-Pathway Oligomer At Acidic Ph, Pierre O. Souillac, Vladimir N. Uversky, Ian S. Millett, Ritu Khurana, Sebastian Doniach, Anthony L. Fink

Molecular Medicine Faculty Publications

Biophysical Properties Of The Synucleins And Their Propensities To Fibrillate: Inhibition Of Α-Synuclein Assembly By Β- And Γ-Synucleins, Vladimir N. Uversky, Jie Li, Pierre O. Souillac, Ian S. Millett, Sebastian Doniach, Ross Jakes, Michael Goedert, Anthony L. Fink

Molecular Medicine Faculty Publications

Evidence For A Partially Folded Intermediate In Α-Synuclein Fibril Formation, Vladimir N. Uversky, Jie Li, Anthony L. Fink

Molecular Medicine Faculty Publications

Is Congo Red An Amyloid-Specific Dye?, Ritu Khurana, Vladimir N. Uversky, Liza Nielsen, Anthony L. Fink

Molecular Medicine Faculty Publications

Metal-Triggered Structural Transformations, Aggregation, And Fibrillation Of Human Α-Synuclein: A Possible Molecular Link Between Parkinson′S Disease And Heavy Metal Exposure, Vladimir N. Uversky, Jie Li, Anthony L. Fink

Molecular Medicine Faculty Publications

Stabilization Of Partially Folded Conformation During Α-Synuclein Oligomerization In Both Purified And Cytosolic Preparations, Vladimir N. Uversky, He-Jin Lee, Jie Li, Anthony L. Fink, Seung-Jae Lee

Molecular Medicine Faculty Publications

Cannabinoids And The Immune System, Thomas W. Klein, Catherine A. Newton, Herman Friedman

Molecular Medicine Faculty Publications