A) PCB chemical structure with labeled (A-D) pyrolle rings (oxygen atoms are in red and nitrogen in blue); B) Schematic of HSA structure with domains and ligand binding sites labeled; Radius of gyration (Rg) values (C) and 2D RMDS plots for free HSA (D), HSA-PCB(IIA) (E), and HSA-PCB(IB) (F) during 300 ns molecular dynamic simulation.

<p>A) PCB chemical structure with labeled (A-D) pyrolle rings (oxygen atoms are in red and nitrogen in blue); B) Schematic of HSA structure with domains and ligand binding sites labeled; Radius of gyration (Rg) values (C) and 2D RMDS plots for free HSA (D), HSA-PCB(IIA) (E), and HSA-PCB(IB) (F) during 300 ns molecular dynamic simulation.</p

(A) Temperature dependence of 0.5 μM HSA ellipticity at 222 nm in the presence and absence of 0.5 μM PCB; (B) Temperature dependence of 1 μM HSA fluorescence at 340 nm in the presence and absence of 1 μM PCB (λ_EX = 280 nm); (C) SDS-PAGE profile after trypsin digestion of 3.8 μM HSA in the presence and absence of 3.8 μM PCB.

<p>Lane K: HSA without trypsin; lane M: MW markers; lanes 1–6 correspond to digestion times 0.5, 2, 5, 10, 30, and 60 min without PCB, respectively; lanes 7–12 correspond to digestion times 0.5, 2, 5, 10, 30 and 60 min with PCB, respectively.</p

Noncovalent interactions of bovine α-lactalbumin with green tea polyphenol, epigalocatechin-3-gallate

Bovine alpha-lactalbumin (ALA) is an important Ca-binding protein of milk. Epigallocatechin-3-gallate (EGCG) is the major and the most biologically active catechin of green tea, which has the highest binding affinity to whey proteins due to galloyl functional group. In this study experimental and computational methods were used to investigate noncovalent interactions of EGCG and ALA. Binding affinity of EGCG for ALA, determined by fluorescence quenching analysis, was in the range described for complexes of EGCG and other dietary proteins, and lower than affinity of some phenolic compounds to ALA. Based on circular dichroism and Fourier transform infrared spectroscopy spectra, binding of EGCG change ALA conformation inducing alpha-helix to beta-structures transition. The isothermal titration calorimetry results suggest that the binding of EGCG to ALA is enthalpically favorable. The docking analysis shows that EGCG binds in the hydrophobic pocket at the entrance of cleft between alpha-helical and beta-sheetrich domains and includes residues of aromatic cluster II. Uptake of ALA by monocytes proceeds at a slower rate in the presence of EGCG suggesting that EGCG binding may impair uptake of ALA by antigen-presenting cells. ALA, being of low cost and widely available protein, can serve as suitable delivery system for EGCG, as well as for food fortification with this bioactive catechin. (C) 2016 Elsevier Ltd. All rights reserved.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3585

Calculated RMSF values (Å) from molecular dynamics simulation of free HSA, HSA-PCB(IB), and HSA-PCB(IIA).

<p>RMSF values along whole protein sequence (A), sum of RMSF values of each HSA domain (B), and difference of RMSF values between PCB-HSA complexes and free HSA, with marked amino acid (aa) residues involved in PCB binding for site IB (C), and for site IIA (D).</p

Covalent binding of food-derived blue pigment phycocyanobilin to bovine β-lactoglobulin under physiological conditions

In this study, we investigated structural aspects of covalent binding of food derived blue pigment phycocyanobilin (PCB) to bovine beta-lactoglobulin (BLG), major whey protein, by spectroscopic, electrophoretic, mass spectrometry and computational methods. At physiological pH (7.2), we found that covalent pigment binding via free cysteine residue is slow (k(a)=0.065 min(-1)), of moderate affinity (K-a=4x10(4) M-1), and stereo-selective. Binding also occurs at a broad pH range and under simulated gastrointestinal conditions. Adduct formation rises with pH, and in concentrated urea (k(a)=0.101 min(-1)). The BLG-PCB adduct has slightly altered secondary and tertiary protein structure, and bound PCB has higher fluorescence and more stretched conformation than free chromophore. Combination of steered molecular dynamic for disulfide exchange, non-covalent and covalent docking, favours Cys119 residue in protein calyx as target for covalent BLG-PCB adduct formation. Our results suggest that this adduct can serve as delivery system of bioactive PCB

Catalogue Maison Bigot [titres “Viens dans ma nacelle” => “Bazeilles”]

Catalogue Maison Bigot, 157 rue du Temple [Paris] : “Romances et chansons nouvelles” (verso “Sommes nous prêts ?”) ; titres : “Viens dans ma nacelle => “Bazeilles” ; quatre colonnes par deux foix (titres, auteurs, compositeurs, genres) ; interprètes crédités dans la colonne “genre” : Marius Richard, Mercadier, Amiati, Debailleul, Paulus, B. Delahaye, Gibert, Garnier [Léon Garnier], d’Aubreuil [Daubreuil ?], Antony [Antony Lassaigne], Duhem [Émile Duhem], Canon [Fernande Canon], Bourgès, Bonnet, E. Faure [Elise Faure], Dlle (Mlle?) Derly, Libert, Caudieux, Leduc, Judith, G. Lange [Gabrielle Lange], Mme Barnoll, Kaiser [Augustine Kaïser], Limat [Louis Limat], Farville, Réval [Jules Réval], Velly [Louis Velly], Plessis [Henri Plessis] ; datation par analyse des titres 1886 (hypothèse à confirmer)

Conformational stability of digestion-resistant peptides of peanut conglutins reveals the molecular basis of their allergenicity

Conglutins represent the major peanut allergens and are renowned for their resistance to gastrointestinal digestion. Our aim was to characterize the digestion-resistant peptides (DRPs) of conglutins by biochemical and biophysical methods followed by a molecular dynamics simulation in order to better understand the molecular basis of food protein allergenicity. We have mapped proteolysis sites at the N- and C-termini and at a limited internal segment, while other potential proteolysis sites remained unaffected. Molecular dynamics simulation showed that proteolysis only occurred in the vibrant regions of the proteins. DRPs appeared to be conformationally stable as intact conglutins. Also, the overall secondary structure and IgE-binding potency of DRPs was comparable to that of intact conglutins. The stability of conglutins toward gastro-intestinal digestion, combined with the conformational stability of the resulting DRPs provide conditions for optimal exposure to the intestinal immune system, providing an explanation for the extraordinary allergenicity of peanut conglutins