1,720,972 research outputs found
Capillary electrophoresis in vitro separation of Abeta oligomers as drug targets: the sample preparation issue
No full textCharacterisation by Capillary Electrophoresis of wild type and new naturally amyloidogenic variant of beta2-microglobulin
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Optimisation of CE-ESI-MS platform for intact protein analysis: conformational studies on beta2-microglobulin.
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Integrated strategies for drug discovery: capillary electrophoresis, mass spectrometry and in silico studies
No full textScreening di legame farmaco-proteina e di bioattivita' di ligandi mediante tecniche analitiche separative e studi in silic
Characterization of different variants of beta2-microglobulin by capillary electrophoresis and high-resolution mass spectrometry
No full textAmyloidoses are clinical disorders caused by deposition of insoluble fibrils, derived from misfolding and aggregation of a soluble protein. Beta2-microglobulin is a globular amyloidogenic protein responsible for dialysis related amyloidosis (DRA), a severe complication that occurs in patients undergoing chronic hemodialysis. [1]. The first natural variant of beta2-microglobulin (D76N), recently discovered, is instead responsible for a hereditary amyloidosis. [2]. The aggregation process of beta2-microglobulin monomer into fibrils is a complex and still uncertain mechanism where protein misfolding is a key event. A characterization of partially structured intermediates of a protein folding has relevant interest as such species play a significant role in the fibrillogenesis. Interestingly, one of the two intermediates of the folding pathway of beta2-microglobulin (known as I2), is significantly populated under physiological conditions and is more aggregation-prone. As I2 slowly interconverts into the native form (N), a CE method previously afforded the monitoring of N and I2 at equilibrium. CE results also showed that the values of free energy of unfolding are correlated to the population of these intermediate conformers. [3]. Based on these data, CE is herein used to characterize copopulated conformational ensembles of beta2-microglobulin variants known to have different amyloidogenicity. Several isoforms have been selected, including full-length and truncated beta2-microglobulin identified in DRA amyloid deposits, isoforms artificially created for stability studies and the new D76N. These proteins are analyzed by CE and HR-MS. The mass spectra provide important information, as each spectrum is characterized by its own m/z CSD which corresponds to different conformations at equilibrium. [4]
Separation and characterisation of beta2-microglobulin folding conformers by ion-exchange liquid chromatography and ion-exchange liquid chromatography-mass spectrometry
Full text linkIn this work we present for the first time the use of ion-exchange liquid chromatography to separate the native form and a partially structured intermediate of the folding of the amyloidogenic protein beta2-microglobulin. Using a strong anion-exchange column that accounts for the differences in charge exposure of the two conformers, a LC-UV method is initially optimized in terms of mobile phase pH, composition and temperature. The preferred mobile phase conditions that afford useful information were found to be 35 mM ammonium formate, pH 7.4 at 25°C. The dynamic equilibrium of the two species is demonstrated upon increasing the concentration of acetonitrile in the protein sample. Then, the chromatographic method is transferred to MS detection and the respective charge state distributions of the separated conformers are identified. The LC-MS results demonstrate that one of the conformers is partially unfolded, compared with the native and more compact species. The correspondence with previous results obtained in free solution by capillary electrophoresis suggest that strong ion exchange LC-MS does not alter beta2-microglobulin conformation and maintains the dynamic equilibrium already observed between the native protein and its folding intermediate
Prolidase deficiency may be reversed by hematopietic stem cell transplantation: CE analysis of dipeptides in urine and monitoring of prolidase activity in blood.
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