1. Ionomic and metabolomic changes in mercury and selenium exposed plants and animals by X - ray and FTIR spectrometryKatarina Vogel-Mikuš, Iztok Arčon, Jože Grdadolnik, Petra Gregorič, Anja Kavčič, 2018, objavljeni povzetek znanstvenega prispevka na konferenci Najdeno v: osebi
Ključne besede: mercury, selenium, plants, animals
Objavljeno: 12.09.2018; Ogledov: 2528; Prenosov: 0
 Polno besedilo (62,45 KB) |
2. The finite size effects and two-state paradigm of protein foldingVladimir N. Uversky, Jože Grdadolnik, Artem Badasyan, Matjaž Valant, 2021, izvirni znanstveni članek Opis: The coil to globule transition of the polypeptide chain is the physical phenomenon behind the folding of globular proteins. Globular proteins with a single domain usually consist of about 30 to 100 amino acid residues, and this finite size extends the transition interval of the coil-globule phase transition. Based on the pedantic derivation of the two-state model, we introduce the number of amino acid residues of a polypeptide chain as a parameter in the expressions for two cooperativity measures and reveal their physical significance. We conclude that the k2 measure, defined as the ratio of van ’t Hoff and calorimetric enthalpy is related to the degeneracy of the denatured state and describes the number of cooperative units involved in the transition; additionally, it is found that the widely discussed k2=1 is just the necessary condition to classify the protein as the two-state folder. We also find that Ωc, a quantity not limited from above and growing with system size, is simply proportional to the square of the transition interval. This fact allows us to perform the classical size scaling analysis of the coil-globule phase transition. Moreover, these two measures are shown to describe different characteristics of protein folding
Najdeno v: osebi
Ključne besede: protein folding, two-state model, size scaling, thermodynamic cooperativity
Objavljeno: 24.02.2021; Ogledov: 917; Prenosov: 34
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3. Implicit water model within the Zimm-Bragg approach to analyze experimental data for heat and cold denaturation of proteinsJože Grdadolnik, Matjaž Valant, Sh. A. Tonoyan, Artem Badasyan, 2021, izvirni znanstveni članek Opis: Studies of biopolymer conformations essentially rely on theoretical models that are routinely
used to process and analyze experimental data. While modern experiments allow study of
single molecules in vivo, corresponding theories date back to the early 1950s and require an
essential update to include the recent significant progress in the description of water. The
Hamiltonian formulation of the Zimm-Bragg model we propose includes a simplified, yet
explicit model of water-polypeptide interactions that transforms into the equivalent implicit
description after performing the summation of solvent degrees of freedom in the partition
function. Here we show that our model fits very well to the circular dichroism experimental
data for both heat and cold denaturation and provides the energies of inter- and intra-
molecular H-bonds, unavailable with other processing methods. The revealed delicate
balance between these energies determines the conditions for the existence of cold dena-
turation and thus clarifies its absence in some proteins.
Najdeno v: osebi
Ključne besede: protein folding, cold denaturation, water, Zimm-Bragg model
Objavljeno: 06.05.2021; Ogledov: 847; Prenosov: 3
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4. 1,8-dihydroxy naphthalene (DHN) - melanin confers tolerance to cadmium in isolates of melanised dark septate endophytesMarjana Regvar, Jože Grdadolnik, Iztok Arčon, Katarina Vogel-Mikuš, Matevž Likar, Mateja Potisek, 2021, izvirni znanstveni članek Opis: The contribution of 1,8-dihydroxy naphthalene (DHN) melanin to cadmium (Cd) tolerance in two dark septate
endophytes (DSE) of the genus Cadophora with different melanin content was investigated in vitro. The DSE
isolate Cad#148 with higher melanin content showed higher tolerance to Cd than the less melanised Cad#149.
Melanin synthesis was significantly reduced by Cd in both isolates with uninhibited melanin synthesis, in a dosedependent
manner. Inhibition of melanin synthesis by tricyclazole reduced the relative growth of Cad#148
exposed to Cd and did not affect Cad#149. Cd accumulation was not altered by tricyclazole in the two isolates,
but it increased catalase and reduced glutathione reductase activity in more melanised Cad#148, indicating
higher stress levels. In contrast, in Cad#149 the enzyme activity was less affected by tricyclazole, indicating a
more pronounced role of melanin-independent Cd tolerance mechanisms. Cd ligand environment in fungal
mycelia was analysed by extended EXAFS (X-ray absorption fine structure). It revealed that Cd was mainly bound
to O- and S-ligands, including hydroxyl, carboxyl, phosphate and thiol groups. A similar proportion of S- and Oligands
(~35% and ~65%) were found in both isolates with uninhibited melanin synthesis. Among O-ligands
two types with Cd-O-C- and Cd-O-P- coordination were identified. Tricyclazole altered Cd-O- ligand environment
in both fungal isolates by reducing the proportion of Cd-O-C- and increasing the proportion of Cd-O-P coordination.
DHN-melanin, among other tolerance mechanisms, significantly contributes to Cd tolerance in more
melanised DSE fungi by immobilising Cd to hydroxyl groups and maintaining the integrity of the fungal cell wall.
Najdeno v: osebi
Ključne besede: DSE, melanin, Cd tolerance, inhibitor tricyclazole, antioxidant enzymes, EXAFS
Objavljeno: 13.07.2021; Ogledov: 694; Prenosov: 0
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