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    Wyświetlanie 1-13 z 13
    Tytuł:
    Quercetin influences BSA alpha-helical structures of native, ACR- and NaNO2-modified BSAs
    Autorzy:
    Rorbach-Dolata, Anna
    Żurawska-Płaksej, Ewa
    Piwowar, Agnieszka
    Powiązania:
    https://bibliotekanauki.pl/articles/895290.pdf
    Data publikacji:
    2018-12-31
    Wydawca:
    Polskie Towarzystwo Farmaceutyczne
    Tematy:
    albumin
    quercetin
    nitrosylation
    alkylation
    conformational changes
    circular dichroism
    Opis:
    Quercetin (QUE) is a plant flavonoid with a multifarious spectrum of properties. It is a prominent component of the human diet, considered to be safe and beneficial for human health. Acrylamide (ACR) and sodium nitrate III (NaNO2) are also present in the diet and may demonstrate adverse and toxic effects on the macromolecules and tissues of the human organism. Albumin, the most abundant blood protein, is the most susceptible to the action of various exogenous factors, which may lead to structural damage and functional disturbances. The aim of this study was to estimate ACR- and NaNO2-induced changes in the secondary structure of bovine serum albumin (BSA), using circular dichroism (CD), and to determine the impact of quercetin on these modifications. BSA was incubated with ACR and NaNO2 solutions in the absence and presence of QUE in two different concentrations (3 mM and 500 µM), and changes in albumin alpha-helical structure were determined by CD. BSA secondary structure was vulnerable to alterations upon treatment with acrylamide and NaNO2, as well as quercetin. QUE, depending on concentration and incubation time, caused a decrease of around 13-19% in the alpha-helix content of BSA molecules, but also prevented the changes in the protein alpha-helical structure initiated by ACR and NaNO2. The most spectacular inhibition was revealed for QUE in lower concentrations after 24h of incubation with NaNO2. Although QUE reveals protective effect towards albumin modifications, it is difficult to unambiguously define whether this effect is advantageous, because quercetin itself causes alterations in BSA structure.
    Źródło:
    Acta Poloniae Pharmaceutica - Drug Research; 2018, 75, 6; 1339-1346
    0001-6837
    2353-5288
    Pojawia się w:
    Acta Poloniae Pharmaceutica - Drug Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Structural and functional changes of bovine carbonic anhydrase as a consequence of temperature.
    Autorzy:
    Sarraf, N
    Saboury, A
    Ranjbar, B
    Moosavi-Movahedi, A
    Powiązania:
    https://bibliotekanauki.pl/articles/1041543.pdf
    Data publikacji:
    2004
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    activation energy
    Arrhenius plot
    circular dichroism
    bovine carbonic anhydrase
    Opis:
    The temperature dependence of the activity and structure of the enzyme carbonic anhydrase was studied. The Arrhenius plot shows a jump which is seen usually in proteins with more than one subunit or with one subunit but more than one domain. Since carbonic anhydrase has only one subunit with one domain, the fine conformational changes of the protein motifs could only be detected through circular dichroism polarimetry. It seems that the jump in Arrhenius plot is a result of some slight structural changes in the secondary and tertiary structures of the enzyme.
    Źródło:
    Acta Biochimica Polonica; 2004, 51, 3; 665-671
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Interaction of an anticancer ruthenium complex HInd[RuInd2Cl4] with cytochrome c.
    Autorzy:
    Trynda-Lemiesz, Lilianna
    Powiązania:
    https://bibliotekanauki.pl/articles/1043344.pdf
    Data publikacji:
    2004
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    cytochrome c
    Ruthenium(III) complexes
    circular dichroism
    apocytochrome c
    Opis:
    Cytochrome c is an important electron transfer protein in the respiratory chain, shuttling electrons from cytochrome c reductase to cytochrome c oxidase. Extensive chemical modification studies indicate significant electrostatic interactions between these proteins and show that all structural and conformational changes of cytochrome c can influence the electron transport. In the present work we examine the effect of an anticancer ruthenium complex, trans-Indazolium (bisindazole) tetrachlororuthenate(III) (HInd[RuInd2Cl4]), on the conformation of cytochrome c, the state of the heme moiety, formation of the protein dimer and on the folding state of apocytochrome c. For this purpose, gel-filtration chromatography, absorption second derivative spectroscopy, circular dichroism (CD) and inductively coupled plasma atomic emission spectroscopy (ICP(AES)) were used. The present data have revealed that binding of the potential anticancer drug HInd[RuInd2Cl4] complex to cytochrome c induces a conformation of the protein with less organized secondary and tertiary structure.
    Źródło:
    Acta Biochimica Polonica; 2004, 51, 1; 199-205
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Interaction of anesthetic supplement thiopental with human serum albumin
    Autorzy:
    Khan, Shahper
    Islam, Barira
    Rajeswari, M
    Usmani,, Hammad
    Khan, Asad
    Powiązania:
    https://bibliotekanauki.pl/articles/1040762.pdf
    Data publikacji:
    2008
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    thiopental
    fluorescence resonance energy transfer
    thermodynamics
    FT-IR
    circular dichroism
    Opis:
    Thiopental (TPL) is a commonly used barbiturate anesthetic. Its binding with human serum albumin (HSA) was studied to explore the anesthetic-induced protein dysfunction. The basic binding interaction was studied by UV-absorption and fluorescence spectroscopy. An increase in the binding affinity (K) and in the number of binding sites (n) with the increasing albumin concentration was observed. The interaction was conformation-dependent and the highest for the F isomer of HSA, which implicates its slow elimination. The mode of binding was characterized using various thermodynamic parameters. Domain II of HSA was found to possess a high affinity binding site for TPL. The effect of micro-metal ions on the binding affinity was also investigated. The molecular distance, r, between donor (HSA) and acceptor (TPL) was estimated by fluorescence resonance energy transfer (FRET). Correlation between the stability of the TPL-N and TPL-F complexes and drug distribution is discussed. The structural changes in the protein investigated by circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy reflect perturbation of the albumin molecule and provide an explanation for the heterogeneity of action of this anesthetic.
    Źródło:
    Acta Biochimica Polonica; 2008, 55, 2; 399-409
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    GTP-binding properties of the membrane-bound form of porcine liver annexin VI.
    Autorzy:
    Kirilenko, Aneta
    Golczak, Marcin
    Pikuła, Sławomir
    Bandorowicz-Pikuła, Joanna
    Powiązania:
    https://bibliotekanauki.pl/articles/1044028.pdf
    Data publikacji:
    2001
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    annexin VI
    GTP-binding domain
    TNP-GTP
    circular dichroism
    GTP binding
    Opis:
    Annexin VI (AnxVI) of molecular mass 68-70 kDa belongs to a multigenic family of ubiquitous Ca2+ - and phospholipid-binding proteins. In this report, we describe the GTP-binding properties of porcine liver AnxVI, determined with a fluorescent GTP analogue, 2'-(or 3')-O-(2,4,6-trinitrophenyl)guanosine 5'-triphosphate (TNP-GTP). The optimal binding of TNP-GTP to AnxVI was observed in the presence of Ca2+ and asolectin liposomes, as evidenced by a 5.5-fold increase of TNP-GTP fluorescence and a concomitant blue shift (by 17 nm) of its maximal emission wavelength. Titration of AnxVI with TNP-GTP resulted in the determination of the dissociation constant (Kd) and binding stoichiometry that amounted to 1.3 μM and 1:1 TNP-GTP/AnxVI, mole/mole, respectively. In addition, the intrinsic fluorescence of the membrane-bound form of AnxVI was quenched by TNP-GTP and this was accompanied by fluorescence resonance energy transfer (FRET) from AnxVI Trp residues to TNP-GTP. This indicates that the GTP-binding site within the AnxVI molecule is probably located in the vicinity of a Trp-containing domain of the protein. By controlled proteolysis of human recombinant AnxVI, followed by purification of the proteolytic fragments by affinity chromatography on GTP-agarose, we isolated a 35 kDa fragment corresponding to the N-terminal half of AnxVI containing Trp192. On the basis of these results, we suggest that AnxVI is a GTP-binding protein and the binding of the nucleotide may have a regulatory impact on the interaction of annexin with membranes, e.g. formation of ion channels by the protein.
    Źródło:
    Acta Biochimica Polonica; 2001, 48, 4; 851-865
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Methods of peptide conformation studies.
    Autorzy:
    Biedrzyński, Andrzej
    Powiązania:
    https://bibliotekanauki.pl/articles/1044052.pdf
    Data publikacji:
    2001
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    fluorescence resonance energy transfer
    NMR
    circular dichroism
    peptide conformation
    hydrogen exchange
    Opis:
    In solution most of the peptides assume multiple flexible conformations. Determination of the dominant conformers and evaluation of their populations is the aim of peptide conformation studies, in which theoretical and experimental methods play complementary roles. Molecular dynamics or Monte Carlo methods are quite effective in searching the conformational space accessible to a peptide but they are not able to estimate, precisely enough, the populations of various conformations. Therefore, they must be supplemented by experimental data. In this paper, a short review of the experimental methods, most widely used in peptide conformational studies, is presented. Among them NMR plays the leading role. Valuable information is also obtained from hydrogen exchange, fluorescence resonance energy transfer, and circular dichroism measurements. The advantages and shortcomings of these methods are discussed.
    Źródło:
    Acta Biochimica Polonica; 2001, 48, 4; 1091-1099
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Protein thermal stabilization in aqueous solutions of osmolytes
    Autorzy:
    Bruździak, Piotr
    Panuszko, Aneta
    Jourdan, Muriel
    Stangret, Janusz
    Powiązania:
    https://bibliotekanauki.pl/articles/1038842.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    water structure
    protein stability
    circular dichroism
    FT-IR spectroscopy
    DFT calculations
    Opis:
    Proteins' thermal stabilization is a significant problem in various biomedical, biotechnological, and technological applications. We investigated thermal stability of hen egg white lysozyme in aqueous solutions of the following stabilizing osmolytes: Glycine (GLY), N-methylglycine (NMG), N,N-dimethylglycine (DMG), N,N,N-trimethylglycine (TMG), and trimethyl-N-oxide (TMAO). Results of CD-UV spectroscopic investigation were compared with FTIR hydration studies' results. Selected osmolytes increased lysozyme's thermal stability in the following order: Gly>NMG>TMAO≈DMG>TMG. Theoretical calculations (DFT) showed clearly that osmolytes' amino group protons and water molecules interacting with them played a distinctive role in protein thermal stabilization. The results brought us a step closer to the exact mechanism of protein stabilization by osmolytes.
    Źródło:
    Acta Biochimica Polonica; 2016, 63, 1; 65-70
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Size, shape and secondary structure of calponin.
    Autorzy:
    Czuryło, Edward
    Eimer, Wolfgang
    Kulikova, Natalia
    Hellweg, Thomas
    Powiązania:
    https://bibliotekanauki.pl/articles/1044328.pdf
    Data publikacji:
    2000
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    dynamic light scattering
    secondary structure prediction
    calponin
    circular dichroism
    secondary structure estimation
    Opis:
    The overall size and shape of the chicken gizzard calponin (CaP) h1 molecule was investigated by dynamic light scattering (DLS) measurements. From the DLS experiments, a z-averaged translational diffusion coefficient is derived (5.75 ± 0.3) × 10-7cm2s-1, which corresponds to a hydrodynamic radius of 3.72 nm for calponin. The frictional ratio (1.8 for the unhydrated molecule and 1.5 for the hydrated one) suggests a pronounced anisotropic structure for the molecule. An ellipsoidal model in length 19.4 nm and with a diameter of 2.6 nm used for hydrodynamic calculations was found to reproduce the DLS experimental data. The evaluation of the secondary structure of CaP h1 from the CD spectra by two independent methods has revealed that it contains, on average, 23% helix, 19% β-strand, 18% β-turns and loops, and 40% of remainder structures. These values are in good agreement with those predicted from the amino-acid sequence. Predictions used for CaP h1 were applied to other isoforms of known sequences and revealed that all calponins share a common secondary structure. Moreover, the predicted structure of the calponin CH domain is identical to that found by X-ray studies of the spectrin, fimbrin and utrophin CH domains.
    Źródło:
    Acta Biochimica Polonica; 2000, 47, 3; 791-806
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Circular dichroism analysis for multidomain proteins: studies of the irreversible unfolding of Hepatitis C virus helicase
    Autorzy:
    Gozdek, Agnieszka
    Stankiewicz-Drogoń, Anna
    Poznański, Jarosław
    Boguszewska-Chachulska, Anna
    Powiązania:
    https://bibliotekanauki.pl/articles/1040814.pdf
    Data publikacji:
    2008
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    Lumry-Eyring model
    Hepatitis C virus
    protein unfolding
    circular dichroism
    NS3 helicase
    Opis:
    The non-structural protein 3 (NS3) of Hepatitis C virus (HCV) is a bifunctional enzyme with RNA-dependent NTPase/RNA helicase and serine protease activities, and thus represents a promising target for anti-HCV therapy. These functions are performed by two distinct moieties; the N-terminal protease domain and the C-terminal helicase domain that further folds into three structural subdomains. To obtain lower molecular mass proteins suitable for nuclear magnetic resonance studies of helicase-inhibitor complexes, helicase domains 1, 2, and 1+2 devoid of a hydrophobic β-loop were overexpressed and purified. Circular dichroism studies were carried out to confirm the secondary structure content and to determine thermodynamic parameters describing the stability of the proteins. Both thermal and GuHCl-induced unfolding experiments confirmed the multidomain organization of the helicase. The unfolding transition observed for domain 1+2 was in agreement with the model of two well-resolved successive steps corresponding to the independent unfolding of domains 1 and 2, respectively. In the case of the full-length helicase, the presence of domain 3 remarkably changed the transition profile, leading to fast and irreversible transformation of partially unfolded protein.
    Źródło:
    Acta Biochimica Polonica; 2008, 55, 1; 57-66
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Circular dichroism and aggregation studies of amyloid β (11-8) fragment and its variants.
    Autorzy:
    Juszczyk, Paulina
    Kołodziejczyk, Aleksandra
    Grzonka, Zbigniew
    Powiązania:
    https://bibliotekanauki.pl/articles/1041423.pdf
    Data publikacji:
    2005
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    secondary structure studies
    thioflavine T assay
    aggregation studies.
    Alzheimer's disease
    amyloid β
    circular dichroism (CD)
    Opis:
    Aggregation of Aβ peptides is a seminal event in Alzheimer's disease. Detailed understanding of Aβ assembly would facilitate the targeting and design of fibrillogenesis inhibitors. Here comparative conformational and aggregation studies using CD spectroscopy and thioflavine T fluorescence assay are presented. As a model peptide, the 11-28 fragment of Aβ was used. This model peptide is known to contain the core region responsible for Aβ aggregation. The structural and aggregational behaviour of the peptide was compared with the properties of its variants corresponding to natural, clinically relevant mutants at positions 21-23 (A21G, E22K, E22G, E22Q and D23N). In HFIP (hexafluoro-2-propanol), a strong α-helix inducer, the CD spectra revealed an unexpectedly high amount of β-sheet conformation. The aggregation process of Aβ(11-28) variants provoked by water addition to HFIP was found to be consistent with a model of an α-helix-containing intermediate. The aggregation propensity of all Aβ(11-28) variants was also compared and discussed.
    Źródło:
    Acta Biochimica Polonica; 2005, 52, 2; 425-431
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Eksperymentalne i teoretyczne oznaczanie konfiguracji absolutnej związków chiralnych metodami chiralooptycznymi
    Experimental and theoretical determination of the absolute configuration of chiral molecules by chiroptical methods
    Autorzy:
    Kwit, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/171859.pdf
    Data publikacji:
    2011
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    struktura
    chiralność
    aktywność optyczna
    dichroizm kołowy
    skręcalność optyczna
    structure
    chirality
    optical activity
    circular dichroism
    optical rotation
    Opis:
    Chirality is of paramount importance in chemistry and life sciences. Electronic circular dichroism (ECD) as well as optical rotation (OR) are fundamental properties of chiral molecules. These chiroptical properties provide rich information about conformation and configuration of the molecules. Although empirical correlations between chiroptical phenomena, mostly ECD, and molecular stereochemistry have existed for some time, the development of new accurate theoretical methods opened new opportunities for correlation of chiroptical properties with structure. Computational chemistry has made an amazing progress during the past two decades, moving this highly specialized discipline into the mainstream, and making a renaissance in chiroptical methods. This short review is meant as an introduction to the modern approach to optical activity of chiral molecules. Some illustrative applications will put the emphasis on practical applications of the theoretical/experimental analysis of complex molecules including highly flexible bistramide C and noncovalently bonded donor-acceptor dyad. The importance of the solvent effect is briefly discussed and a typical methodology is described and its strengths and weak points are commented.
    Źródło:
    Wiadomości Chemiczne; 2011, 65, 1-2; 33-58
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    How to study G-quadruplex structures
    Autorzy:
    Malgowska, M.
    Gudanis, D.
    Teubert, A.
    Dominiak, G.
    Gdaniec, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/80131.pdf
    Data publikacji:
    2012
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    guanine
    DNA molecule
    RNA molecule
    molecular structure
    intramolecular structure
    intermolecular structure
    G-quadruplex structure
    circular dichroism spectroscopy
    ultraviolet spectroscopy
    electrospray ionization mass spectrometry
    nuclear magnetic resonance
    Źródło:
    BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2012, 93, 4
    0860-7796
    Pojawia się w:
    BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Photoacoustic transformation at oppositely directed interaction electromagnetic waves in the magnetoactive two-layer medium
    Transformacja fotoakustyczna przy oddziaływaniu przeciwbieżnych wiązek elektromagnetycznych w magnetoaktywnych ośrodkach dwuwarstwowych
    Autorzy:
    Mityurich, G. S.
    Aleksiejuk, M.
    Sviridova, V. V.
    Serdyukov, A. N.
    Powiązania:
    https://bibliotekanauki.pl/articles/351166.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    photoacoustic signal gas-microphone method
    thermooptical sound generation
    magnetic circular dichroism
    tunnel interference of electromagnetic waves
    metoda foto-akustyczna generacji dźwięku
    magnetoaktywne układy dwuwarstwowe
    termooptyczna genaracja dźwięku
    tunelowa interferencja fal elektromagnetycznych
    Opis:
    The paper treats the thermooptical sound generation in the magnetoactive two-layered medium on the condition of tunnel interference of electromagnetic waves. It were studied the conditions of complete suppression of the photoacoustic signal amplitude in response to the polarization type of oppositely interacting waves, the difference in their initial phases as well as the intensities of one of the oppositely interacted beams. The given paper provides an effective method of managing the thermooptical sound generation in the magnetoactive structural element during the tunnel electromagnetic interference of electromagnetic waves.
    Celem pracy są badania nad foto-akustyczną generacją dźwięku w magnetoaktywnych układach dwuwarstwowych, w warunkach interferencji tunelowej fal elektromagnetycznych. Badano warunki całkowitego wytłumienia amplitudy sygnału fotoakustycznego w funkcji polaryzacji przeciwbieżnych, oddziałujących wzajemnie fal, ich faz początkowych oraz intensywności jednej z przeciwbieżnych wiązek. Praca przedstawia efektywną metodę sterowania termooptyczną generacją dźwięku w strukturach magnetoaktywnych, podczas tunelowej interferencji fal elektromagnetycznych.
    Źródło:
    Archives of Metallurgy and Materials; 2013, 58, 4; 1419-1423
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-13 z 13

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