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    Wyświetlanie 1-9 z 9
    Tytuł:
    A novel cis-peptide bond motif inducing β-turn type VI. The synthesis of enkephalin analogues modified with 4-aminopyroglutamic acid.
    Autorzy:
    Kaczmarek, Krzysztof
    Kaleta, Maciej
    Chung, Nga
    Schiller, Peter
    Zabrocki, Janusz
    Powiązania:
    https://bibliotekanauki.pl/articles/1044069.pdf
    Data publikacji:
    2001
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    constrained enkephalin analogues
    4-aminopyroglutamic acid
    cis-peptide bond
    β-turn mimetic
    Opis:
    A new pathway leading to a mixture of four isomers of 4-aminopyroglutamic acid is described. Michael type addition of Z-ΔAla-OMe to enolates prepared from acylaminomalonates, followed by hydrolysis and decarboxylation give protected 4-aminopyroglutamic acid with the 4-aminopyroglutamic acid with the cis:trans ratio approximately 3:2. This mixture was incorporated into Leu-enkephalin (position 2-3). After separation of peptides it appeared that all analogues were essentially inactive in guinea pig ileum and mouse vas deferens bioassays.
    Źródło:
    Acta Biochimica Polonica; 2001, 48, 4; 1159-1163
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Conformational investigation of α,β-dehydropeptides. XIII. Conformational properties of N-acetyl-α,β-dehydrovaline N',N'-dimethylamide.
    Autorzy:
    Siodłak, Dawid
    Rzeszotarska, Barbara
    Broda, Małgorzata
    Kozioł, Anna
    Kołodziejczyk, Edyta
    Powiązania:
    https://bibliotekanauki.pl/articles/1043332.pdf
    Data publikacji:
    2004
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    ab initio/DFT calculations
    N',N'-dimethylamides
    X-ray crystallography
    α,β-dehydroamino acids
    peptide design
    valine derivative
    Opis:
    The crystal structure of Ac-ΔVal-NMe2 (ΔVal = α,β-dehydrovaline) was determined by X-ray crystallography. The found angles φ = -60° and ψ = 125° correspond exactly to the respective values of the (i + 1)th residue in idealised β-turn II/VIa. Ab initio/DFT studies revealed that the molecule adopts the angle ψ restricted only to about |130°| and very readily attains the angle φ = about -50°. This is in line with its solid-state conformation. Taken together, these data suggest that the ΔVal residue combined with a C-terminal tertiary amide is a good candidate at the (i + 1)th position in a type II/VIa β-turn.
    Źródło:
    Acta Biochimica Polonica; 2004, 51, 1; 145-152
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Conformational properties of N-acetyl-L-alanine N',N'-dimethylamide.
    Autorzy:
    Siodłak, Dawid
    Rzeszotarska, Barbara
    Broda, Małgorzata
    Powiązania:
    https://bibliotekanauki.pl/articles/1043329.pdf
    Data publikacji:
    2004
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    ab initio/DFT calculations
    N-alkylpeptides
    β-turns
    alanine derivative
    N',N'-dimethylamides
    peptide design
    Opis:
    Ab initio/DFT analysis of the conformational properties of free Ac-Ala-NMe2 (N-acetyl-L-alanine-N',N'-dimethylamide) in terms of the N-H···O, N-H···N, C-H···O hydrogen bonds and Cδ+ = Oδ- dipole attractions was performed. The Ala residue combined with the C-terminal tertiary amide prefers an extended conformation and that characteristic of the (i + 1)th position of the βVIb turn. These can be easily remodelled into a structure compatible with the (i + 1)th position of the βII/βVIa turn. The residue has also the potential to adopt the conformation accommodated at both central positions of the βIII/βIII' turn or the (i + 1)th position of the βI/β'I turn.
    Źródło:
    Acta Biochimica Polonica; 2004, 51, 1; 137-143
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Stereochemistry of insect kinin tetrazole analogues and their diuretic activity in crickets.
    Autorzy:
    Nachman, Ronald
    Coast, Geoffrey
    Kaczmarek, Krzysztof
    Williams, Howard
    Zabrocki, Janusz
    Powiązania:
    https://bibliotekanauki.pl/articles/1043327.pdf
    Data publikacji:
    2004
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    constrained insect kinin analogue
    tetrazole
    diuresis
    cis-peptide bond
    β-turn mimetic
    Opis:
    Insect kinin analogues of the sequence Phe-Phe-ψ[CN4]-Ala-Trp-Gly-NH2 containing (L-Phe2,L-Ala3) and (L-Phe2,D-Ala3) stereochemical variants of the tetrazole moiety, a mimic of the type VI β-turn, demonstrate significant agonist and partial antagonist activity, respectively, in a cricket diuretic bioassay. A comparison of the solution conformations of these two stereochemical variants indicates a structural basis for their divergent bioactivities. The (D-Phe2,D-Ala3) stereochemical variant was synthesized and found to demonstrate significant agonist activity. The results further define stereochemical requirements for the diuretic activity of insect kinins in crickets and provide valuable information for the design of biostable analogues capable of disrupting digestive and diuretic processes in pest insects.
    Źródło:
    Acta Biochimica Polonica; 2004, 51, 1; 121-127
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Targeting BACE with small inhibitory nucleic acids - a future for Alzheimers disease therapy?
    Autorzy:
    Nawrot, Barbara
    Powiązania:
    https://bibliotekanauki.pl/articles/1043280.pdf
    Data publikacji:
    2004
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    β-amyloid peptide
    deoxyribozymes
    small interfering RNAs
    hammerhead ribozymes
    Alzheimer's disease
    β-secretase
    Opis:
    β-Secretase, a β-site amyloid precursor protein (APP) cleaving enzyme (BACE), participates in the secretion of β-amyloid peptides (Aβ), the major components of the toxic amyloid plaques found in the brains of patients with Alzheimer's disease (AD). According to the amyloid hypothesis, accumulation of Aβ is the primary influence driving AD pathogenesis. Lowering of Aβ secretion can be achieved by decreasing BACE activity rather than by down-regulation of the APP substrate protein. Therefore, β-secretase is a primary target for anti-amyloid therapeutic drug design. Several approaches have been undertaken to find an effective inhibitor of human β-secretase activity, mostly in the field of peptidomimetic, non-cleavable substrate analogues. This review describes strategies targeting BACE mRNA recognition and its down-regulation based on the antisense action of small inhibitory nucleic acids (siNAs). These include antisense oligonucleotides, catalytic nucleic acids - ribozymes and deoxyribozymes - as well as small interfering RNAs (siRNAs). While antisense oligonucleotides were first used to identify an aspartyl protease with β-secretase activity, all the strategies now demonstrate that siNAs are able to inhibit BACE gene expression in a sequence-specific manner, measured both at the level of its mRNA and at the level of protein. Moreover, knock-down of BACE reduces the intra- and extracellular population of Aβ40 and Aβ42 peptides. An anti-amyloid effect of siNAs is observed in a wide spectrum of cell lines as well as in primary cortical neurons. Thus targeting BACE with small inhibitory nucleic acids may be beneficial for the treatment of Alzheimer's disease and for future drug design.
    Źródło:
    Acta Biochimica Polonica; 2004, 51, 2; 431-444
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Conformational properties of N-acetyl-N-methyl-α,β-dehydroalanine N-methylamide
    Autorzy:
    Macedowska, Agnieszka
    Siodłak, Dawid
    Rzeszotarska, Barbara
    Powiązania:
    https://bibliotekanauki.pl/articles/1041296.pdf
    Data publikacji:
    2006
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    ab initio/DFT calculations
    N-alkylpeptides
    cis-trans isomerisation
    α,β-dehydroamino acids
    peptide design
    Opis:
    The conformational properties of Ac-Δ(Me)Ala-NHMe (N-acetyl-N-methyl-α,β-dehydroalanine N'-methylamide), as the simplest model of N-methyl-α,β-dehydroamino acids, was examined with theoretical methods and in comparison with Ac-ΔAla-NHMe and Ac-ΔAla-NMe2. The N-terminal amide of the Δ(Me)Ala residue easily adopts the configuration cis and the torsion angles φ, ψ are highly flexible. The Δ(Me)Ala residue is a conformational flexibilizer as compared to the parent ΔAla, which is a conformational stiffener. This seems to be the reason why Δ(Me)Ala is found in small natural cyclic peptides, where it ensures the conformational flexibility necessary for biological action.
    Źródło:
    Acta Biochimica Polonica; 2006, 53, 1; 227-232
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Conformational analysis of fragment of human Pin1 ww domain: influence of charged amino-acid residues on β-hairpin structure
    Autorzy:
    Makowska, J.
    Uber, D.
    Żmudzińska, W.
    Chmurzyński, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/1935818.pdf
    Data publikacji:
    2014
    Wydawca:
    Politechnika Gdańska
    Tematy:
    peptide conformation
    β-hairpin
    hPin1 protein
    NMR
    Opis:
    We examined the effect of like-charged residues on the conformation of an original nine amino-acid-residue fragment of the human Pin1 WW domain (hPin1) with the following sequence: Ac-Arg-Met-Ser-Arg-Ser-Ser-Gly-Arg-Val-NH 2 (U9). This was facilitated by CD and NMR spectroscopic measurements, and molecular dynamics calculations. Our ear lier studies suggested that the presence of like-charged residues at the end of a short polypeptide chain composed of nonpolar residues could induce a chain reversal. For the U9 peptide, canonical MD simulations with NMR -derived restraints demonstrated the presence of ensembles of structures with a tendency to form a β -chain reversal. Additionally, thermal stabilities of the peptide under study were measured using differential scanning calorimetry ( DSC ). The estimated well defined phase transition point showed that conformational equilibria in the U9 peptide were strongly dependent on temperature.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2014, 18, 4; 343--349
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Probing of Cu2+ ions binding to A β (5−16) peptide using ITC measurements and MD simulations
    Autorzy:
    Makowska, J.
    Żmudzińska, W.
    Wyrzykowski, D.
    Brzozowski, K.
    Zblewska, H.
    Chmurzyński, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/1938620.pdf
    Data publikacji:
    2016
    Wydawca:
    Politechnika Gdańska
    Tematy:
    A β (5 − 16) fragments
    metal-peptide binding
    isothermal titration calorimetry
    molecular dynamics simulations
    Opis:
    It is shown that probably three residues: His6, His14 and His16 in the original sequence A β (1−42) serve as metal-binding sites for Cu2+ions. On the other hand, there is a possibility that only one of them plays a crucial role in the formation of the{A β (1-42)-Cu2+} complex. The isothermal titration calorimetry (ITC) measurements supported by molecular dynamic simulation (MD) with the NMR-derived restrains were used to investigate the interactions of Cu2+ with A β(5-16), a fragment of the A β(1-42) protein, with the following sequence: Ac-Arg-His-Asp-Ser-Gly-Tyr-Glu-Val-His-His-Gln-Lys-NH2, termed HZ1. The conditional thermodynamic parameters suggest that the formation of the Cu2+-HZ1 complex is both an enthalpy and entropy driven process under the experimental conditions. The studies presented here (after comparison with our previous results) show that the affinity of peptides to copper metal ions depends on two factors: the primary structure (amino acid composition) and the shape of the peptide conformation adopted.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2016, 20, 4; 409-416
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wpływ różnych reszt β-aminokwasowych na zdolności koordynacyjne peptydów wobec jonów metali przejściowych
    The influence of different β-amino acid residues on coordinating abilities of peptides toward transition metal ions
    Autorzy:
    Krzciuk-Gula, Joanna
    Ledwoń, Patrycja
    Staśkiewicz, Agnieszka
    Latajkа, Rafał
    Powiązania:
    https://bibliotekanauki.pl/articles/972289.pdf
    Data publikacji:
    2020
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    β-peptyd
    koordynacja
    jon metalu przejściowego
    β-peptide
    coordination
    transition metal ion
    Opis:
    Peptidomimetics are different groups of compounds which are the modifications of natural occurring peptides - mostly in the sense of the structure. Due to these kind of changes, the new, modified systems are more stable and could act as a tool dedicated in specific biological activity. One of the most important and developed group of peptidomimetics are β-peptides. This review discusses the coordination ability of peptides containing β-amino acid residues incorporated into their sequence. Special attention is given to the importance of βAla residue and metal binding affinity of transition metal ions, especially Cu2+ ion. The coordination process occurs analogously to peptides composed of a-amino acids. The complexes are usually formed initially by coordination of N-terminal amine group and subsequently, with increasing pH value, by deprotonation of amide bonds. The main difference can be observed in the stability and geometry of complexes. Namely, the stability constants of β-peptides are usually slightly lower than in the case of natural analogues. Furthermore, the review presents data according to coordination ability of peptides containing β-amino acids, such as: βAsp, βHis, βCys and βLys. In spite of differences between standard peptides and their analogues, containing β-amino acid residues, there are no very important differences in the model of their coordination with the transition metal ions. However, the comparison of β-peptides and their natural counterparts reveals interesting features, which can be useful for more effective designing of new compounds possessing expected properties.
    Źródło:
    Wiadomości Chemiczne; 2020, 74, 3-4; 285-310
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-9 z 9

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