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Wyświetlanie 1-6 z 6
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:
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:
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 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 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:
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
    Wyświetlanie 1-6 z 6

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