Carbohydr Polym
January 2021
This article describes the preparation of superabsorbent hydrogels made of high acyl gellan without the addition of a crosslinker . Variations of the pH of the medium and different gellan solution concentrations were evaluated. The samples produced were investigated regarding their morphology by scanning electron microscopy, thermal resistance by thermogravimetry, and compressive strength by mechanical testing.
View Article and Find Full Text PDFGene expression is regulated at both the mRNA and protein level through on‐off switches and fine‐tuned control. In their recent study, Edfors (2016) use highly accurate, targeted proteomics methods and examine to what extent the amount of protein produced per mRNA transcript varies across different tissues. They find that the bulk part of protein concentrations is set at a per‐gene level: This relationship, the protein/mRNA ratio, is constant across cell types and tissues, but varies by several orders of magnitude across genes.
View Article and Find Full Text PDFThis study stands out for analyzing distinct ways of preparing hydrogels from deacetylated gellan gum that have high swelling capacity and good thermal resistance. We carried out a thorough investigation, applying various combinations of different experimental parameters. Two preparation methods were evaluated, in which the pH was adjusted before or after thermal treatment of the gellan solution, with subsequent addition of the crosslinking agent, to assess the influence of preparation method on the conformation of the gellan chains regarding formation of double helices.
View Article and Find Full Text PDFThe data described here provide the first large-scale analysis of lysine 63 (K63)-linked polyubiquitin targets. Protein ubiquitination is a prominent post-translational modification, and a variety of ubiquitin chains exists, serving a multitude of functions [1]. The chains differ by the lysine residue by which the ubiquitin monomers are linked.
View Article and Find Full Text PDFOxidative stress is known to affect both translation and protein turnover, but very few large scale studies describe protein expression under stress. We measure protein concentrations in Saccharomyces cerevisiae over the course of 2 h in response to a mild oxidative stress induced by diamide, providing detailed time-resolved information for 815 proteins, with additional data for another ~1,100 proteins. For the majority of proteins, we discover major differences between the global transcript and protein response.
View Article and Find Full Text PDFComp Biochem Physiol C Toxicol Pharmacol
October 2007
Cysteine plays structural roles in proteins and can also participate in electron transfer reactions, when some structural folds provide appropriated environments for stabilization of its sulfhydryl group in the anionic form, called thiolate (RS(-)). In contrast, sulfhydryl group of free cysteine has a relatively high pK(a) (8,5) and as a consequence is relatively inert for redox reaction in physiological conditions. Thiolate is considerable more powerful as nucleophilic agent than its protonated form, therefore, reactive cysteine are present mainly in its anionic form in proteins.
View Article and Find Full Text PDFActa Crystallogr Sect F Struct Biol Cryst Commun
April 2005
Glutaredoxins are small (9-12 kDa) heat-stable proteins that are highly conserved throughout evolution; the glutaredoxin active site (Cys-Pro-Tyr-Cys) is conserved in most species. Five glutaredoxin genes have been identified in Saccharomyces cerevisiae; however, Grx2 is responsible for the majority of oxidoreductase activity in the cell, suggesting that its primary function may be the detoxification of mixed disulfides generated by reactive oxygen species (ROS). Recombinant Grx2 was expressed in Escherichia coli as a 6xHis-tagged fusion protein and purified by nickel-affinity chromatography.
View Article and Find Full Text PDFThe 20 S proteasome core purified from Saccharomyces cerevisiae is inhibited by reduced glutathione (GSH), cysteine (Cys), or the GSH precursor gamma-glutamylcysteine. Chymotrypsin-like activity was more affected by GSH than trypsin-like activity, whereas the peptidylglutamyl-hydrolyzing activity (caspase-like) was not inhibited by GSH. Cys-sulfenic acid formation in the 20 S core was demonstrated by spectral characterization of the Cys-S(O)-4-nitrobenzo-2-oxa-1,3-diazole adduct, indicating that 20 S proteasome Cys residues might react with reduced sulfhydryls (GSH, Cys, and gamma-glutamylcysteine) through the oxidized Cys-sulfenic acid form.
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