RESUMO
The synthesis of three heparin analogues (i.e. compounds VI-VIII) having perphosphorylated thrombin binding domains (TBDs) is reported. These compounds were tested in vitro for their antithrombin III (ATIII)-mediated anti-Xa and antithrombin activities. Conjugates VI and VIII show a remarkable increase in antithrombin activity compared to the structurally related conjugates with persulfated TBDs (i.e. compounds IV and V), whereas compound VII displays a diminished activity.
Assuntos
Antitrombinas/síntese química , Heparina/análogos & derivados , Trombina/metabolismo , Antitrombinas/química , Antitrombinas/metabolismo , Sítios de Ligação , Configuração de Carboidratos , Sequência de Carboidratos , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Dados de Sequência Molecular , FosforilaçãoRESUMO
The syntheses of several heparin-like glycoconjugates (i.e., 16a-f) containing identical AT III binding domains (ABD) and spacers but different thrombin binding domains (TBDs) are described. Biological activities of conjugates 16a-f indicate that the thrombin inhibitory activity is mainly determined by the charge density of the TBD moiety.
Assuntos
Glicoconjugados/síntese química , Glicoconjugados/farmacologia , Heparina/análogos & derivados , Heparina/farmacologia , Oligossacarídeos/síntese química , Trombina/metabolismo , Angiotensina III/metabolismo , Sítios de Ligação , Configuração de Carboidratos , Sequência de Carboidratos , Dermatan Sulfato/química , Desenho de Fármacos , Glicoconjugados/química , Modelos Moleculares , Dados de Sequência Molecular , Oligossacarídeos/química , Oligossacarídeos/farmacologia , Relação Estrutura-AtividadeRESUMO
The in vitro antithrombotic activity of synthetic glycoconjugates I and II, comprising a flexible polyethylene glycol type and a rigid polyglucose type spacer, respectively, are compared to heparin.
Assuntos
Anticoagulantes/farmacologia , Glicoconjugados/farmacologia , Heparina/análogos & derivados , Heparina/farmacologia , Polietilenoglicóis/farmacologia , Trombina/antagonistas & inibidores , Anticoagulantes/síntese química , Anticoagulantes/química , Configuração de Carboidratos , Sequência de Carboidratos , Inibidores do Fator Xa , Glicoconjugados/síntese química , Glicoconjugados/química , Heparina/síntese química , Heparina/química , Humanos , Dados de Sequência Molecular , Fator Plaquetário 4/antagonistas & inibidores , Polietilenoglicóis/síntese química , Polietilenoglicóis/química , Relação Estrutura-AtividadeRESUMO
Electrostatic interactions appear to be important in the conformation and dynamics of DNA four-way junctions. Particularly, the Coulomb repulsion between two approaching phosphate groups at the site of strand exchange is commonly supposed to have a negative influence on the thermodynamic stability of the fully stacked conformation. We synthesized a unimolecular DNA four-way junction containing an uncharged methylene-acetal linkage, -O3'-CH2-O5'-, instead of a regular phosphodiester linkage, -O3'-PO2-O5'-, between two specific residues at the branch-point to examine the effect of charge removal. Complete sequential 1H-NMR assignments of the non-exchangeable base protons and H1'/H2'/H2" sugar protons were obtained with the aid of NOESY and TOCSY experiments. On the basis of the NMR data it is concluded that the stacking arrangement at the branch-point of the modified oligonucleotide is similar to that of the previously studied parent four-way junction. Surprisingly, this is not the stacking arrangement in which the close phosphate-phosphate contact at the site of strand exchange would be absent. Some implications of this novel information regarding the role of the phosphate-phosphate repulsion in four-way junctions are discussed.
Assuntos
DNA/química , Conformação de Ácido Nucleico , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Oligonucleotídeos/química , Isótopos de Fósforo , Prótons , TrítioRESUMO
The naturally occurring DNA-nucleopeptide H-Asp-Ser[5'-pAAAGTAAGCC-3']-Glu-OH was prepared via a solid-phase phosphite triester approach using N-2-(tert-butyldiphenylsilyloxymethyl)benzoyl protected nucleosides. The oligonucleotide was linked via the extremely base-labile oxalyl ester anchor to the solid support.
Assuntos
Bacteriófagos/química , DNA Viral/síntese química , Nucleoproteínas/síntese química , Fragmentos de Peptídeos/síntese química , Proteínas Virais/síntese química , Sequência de Aminoácidos , Bacillus subtilis/química , Bacillus subtilis/genética , Bacteriófagos/genética , Sequência de Bases , Dados de Sequência MolecularRESUMO
The naturally occurring RNA-nucleopeptide H-Ala-Tyr[5'-pUUAAAAC-3']-NH2 is prepared via a solid-phase phosphite triester approach using N-SiOMB/O-TBDMS-protected nucleosides. Preliminary 1H-NMR studies show that the peptidyl unit has a remarkable effect on the conformational behaviour of the RNA moiety in the nucleopeptide.
Assuntos
Oligorribonucleotídeos/química , Fragmentos de Peptídeos/síntese química , Poliovirus/química , RNA Viral/química , Ribonucleoproteínas/síntese química , Proteínas Virais/síntese química , Espectroscopia de Ressonância Magnética , Conformação de Ácido Nucleico , Nucleoproteínas/química , Fragmentos de Peptídeos/química , Ribonucleoproteínas/química , Proteínas Virais/químicaRESUMO
The preparation of the nucleopeptide H-Phe-Tyr-(pATAT)-NH2 could be realized via a solid phase phosphitetriester approach and by using the protected protecting group 2-(tert-butyldiphenylsilyoxymethyl)-benzoyl for the masking of the N6-amino function of deoxyadenosine. The latter protecting group can be removed under mild conditions with fluoride ion.
Assuntos
Bacteriófago phi X 174 , Nucleoproteínas/síntese química , Oligopeptídeos/síntese química , Bacteriófago phi X 174/análise , CromatografiaRESUMO
Use of the protecting groups di-n-butylaminomethylene,2-nitrophenylsulfenyl and the ester of 2-(hydroxymethyl)-9,10-anthraquinone, enabled us for the first time to prepare nucleopeptide fragments containing 2'-deoxyguanosine and a free carboxylic acid group.
Assuntos
Desoxirribonucleoproteínas/síntese química , Oligonucleotídeos/síntese química , Oligopeptídeos/síntese química , Fenômenos Químicos , Química , Espectroscopia de Ressonância Magnética , Estrutura MolecularRESUMO
The monofunctional phosphitylating reagents bis-(N,N-diethylamino)chlorophosphine and salicylchlorophosphine have been applied for the preparation of H-phosphonates of the amino acids serine, threonine and tyrosine. Experimental evidence showed that the latter reagent was less effective for the synthesis of a tyrosine H-phosphonate. The amino acids (peptide) H-phosphonates of serine or threonine proved to be suitable starting compounds for the formation of a phosphate diester bond with the 5'-OH of a d-nucleoside derivative using pivaloyl chloride as the activating reagent.