Hydration dynamics at fluorinated protein surfaces

Water-protein interactions dictate many processes crucial to protein function including folding, dynamics, interactions with other biomolecules, and enzymatic catalysis. Here we examine the effect of surface fluorination on water-protein interactions. Modification of designed coiled-coil proteins by incorporation of 5,5,5-trifluoroleucine or (4S)-2-amino-4-methylhexanoic acid enables systematic examination of the effects of side-chain volume and fluorination on solvation dynamics. Using ultrafast fluorescence spectroscopy, we find that fluorinated side chains exert electrostatic drag on neighboring water molecules, slowing water motion at the protein surface

Recherches archéologiques sur les îles ioniennes /

Bibliography: v. [1], p. 2-3.1. Corfou.-- 2. Céphalonie.-- 3/4/5. Zante. Cérigo. Appendice.Mode of access: Internet

An electron microscopic and biochemical study of the effects of cyclic 3', 5'- AMP, ergotamine or propanolol on the lysosomes of newborn rat hepatocytes

The effects of cyclic 3', 5'-AMP, ergotamine or propranolol on newborn rat liver were studied by using biochemical assays, electron microscopy and quantitative morphometry. Cyclic AMP enhanced the normal postnatal rise in the glycogen-hydrolysing activity of acid alpha 1,4 glucosidase but had no effect on the maltose-hydrolysing activity of the enzyme. The results suggest that these activities may be due to different enzymes. Propranolol prevented the postnatal increase in the glycogen-hydrolysing activity of acid glucosidase and the breakdown of lysosomal glycogen, indicating that these phenomena represent betaadrenergic functions in newbom rats. Ergotamine also inhibited the postnatal increase in this activity and the lysosomal glycogen mobilization. A reasonable explanation for these results is that ergotamine interferes with the action or formation of cyclic AMP

A quantitative description of the insulin-induced ultrastructural changes in newborn rat hepatocytes

The effects of insulin on the ultrastructure of newborn rat hepatocytes were systernatically quantified at satisfactory statistical significance. Insulin prevented the normal postnatal increase in the total volume of lysosomes and the breakdown of glycogen inside these organelles. The lysosomal glycogen-hydrolysing enzyme, acid alpha 1,4 glucosidase was inhibited by the hormone. Insulin also prevented the normal postnatal increase in the total volume of peroxisomes, especially of the crystalloid core-devoid type. The hormone produced an increase in the area of cell membrane, due to the forrnation of many irregular folds of the cell surface. These results constitute good evidence for participation of lysosomes and peroxisomes in the overall glycogen degradation and or gluconeogenesis in the newborn rat hepatocytes

Comparative studies of the proteome, glycoproteome, and N-glycome of clear cell renal cell carcinoma plasma before and after curative nephrectomy

Clear cell renal cell carcinoma is the most prevalent of all reported kidney cancer cases, and currently there are no markers for early diagnosis. This has stimulated great research interest recently because early detection of the disease can significantly improve the low survival rate. Combining the proteome, glycoproteome, and N-glycome data from clear cell renal cell carcinoma plasma has the potential of identifying candidate markers for early diagnosis and prognosis and/or to monitor disease recurrence. Here, we report on the utilization of a multi-dimensional fractionation approach (12P-M-LAC) and LC-MS/MS to comprehensively investigate clear cell renal cell carcinoma plasma collected before (disease) and after (non-disease) curative nephrectomy (n = 40). Proteins detected in the subproteomes were investigated via label-free quantification. Protein abundance analysis revealed a number of low-level proteins with significant differential expression levels in disease samples, including HSPG2, CD146, ECM1, SELL, SYNE1, and VCAM1. Importantly, we observed a strong correlation between differentially expressed proteins and clinical status of the patient. Investigation of the glycoproteome returned 13 candidate glycoproteins with significant differential M-LAC column binding. Qualitative analysis indicated that 62% of selected candidate glycoproteins showed higher levels (upregulation) in M-LAC bound fraction of disease samples. This observation was further confirmed by released N-glycans data in which 53% of identified N-glycans were present at different levels in plasma in the disease vs non-disease samples. This striking result demonstrates the potential for significant protein glycosylation alterations in clear cell renal cell carcinoma cancer plasma. With future validation in a larger cohort, information derived from this study may lead to the development of clear cell renal cell carcinoma candidate biomarkers.12 page(s