RESUMO
The introduction of an aryl ring onto the 4-position of the C-6 benzyl amino group of the Cdk inhibitor roscovitine (2), maintained the potent Cdk inhibition demonstrated by roscovitine (2) as well as greatly improving the antiproliferative activity. A series of C-6 biarylmethylamino derivatives was prepared addressing modifications on the C-6 biaryl rings, N-9 and C-2 positions to provide compounds that displayed potent cytotoxic activity against tumor cell lines. In particular, derivative 21h demonstrated a >750-fold improvement in the growth inhibition of HeLa cells compared to roscovitine (2).
Assuntos
Antineoplásicos/farmacologia , Quinases Ciclina-Dependentes/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Purinas/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Desenho de Fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Células HeLa , Humanos , Estrutura Molecular , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Purinas/síntese química , Purinas/química , Roscovitina , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
Molecular dynamics has been employed to analyze the counterion and water atmospheres around the deoxynucleic guanidine (DNG) duplex G(12)-C(12). These features are compared to those of DNA G(12)-C(12). The chloride counterions of cationic DNG demonstrate fewer penetrations and only fleeting residence times in the minor groove, as opposed to the multi-nanosecond visits seen by sodium ions in DNA minor grooves. The 10 ns simulations also show the differences in hydration patterns between the DNG and DNA duplexes.
Assuntos
DNA/química , Guanidinas/química , Conformação de Ácido Nucleico , Água/química , Cátions Monovalentes/química , Cloretos/química , Elétrons , Solubilidade , Solventes/químicaRESUMO
Replacement of the phosphodiester linkages of DNA and RNA by guanidinium linkages provides DNG and RNG. We report here the order of stability of mixed duplexes (RNG-U5.DNA-A5>>RNA-U5.RNA-A5>RNG-U5.RNA-A5>RNA-U5.DNA-A5>DNA-T5.DNA-A5). The considerable stability of RNG.DNA compared to RNG.RNA is shown to be due to the rigid backbone of RNG existing only in B-form and therefore lowering its affinity for A-RNA. RNG oligomers are putative antigene agents which are specific for DNA and would have minimal competitive binding to ncRNA.
Assuntos
DNA Complementar/química , DNA Complementar/metabolismo , Guanidina/química , Oligorribonucleotídeos/química , Ligação Competitiva , Dicroísmo Circular , Guanidina/metabolismo , Modelos Moleculares , Oligorribonucleotídeos/metabolismo , Uracila/química , Uracila/metabolismoRESUMO
Molecular dynamics is used to investigate the structural properties of the cationic DNA analogue deoxynucleic guanidine (DNG), in which a guanidinium group replaces the phosphate moiety of DNA. This study examines the DNG duplex dodecamers d(Ag)(12).d(Tg)(12) and d(Gg)(12).d(Cg)(12), as well as their DNA counterparts. Watson-Crick base-pairing is maintained in the solvated DNG duplex models during the 5ns simulations. The idealized DNG dodecamers assume many parameters characteristic of the corresponding native DNA, assuming B-DNA conformations. Several helical parameters are rather unique to DNG, including buckle, slide, inclination, propeller, and X-displacement. Fewer transitions in backbone torsions occur in the DNG duplexes compared to those of the DNA, which may result from the greater rigidity of the sp(2) hybridized guanidinium group verses the flexible sp(3) phosphate group. The DNG helices have exceptionally shallow major grooves and very deep minor grooves. The major and minor groove widths of DNG are narrower than those of the respective DNA counterparts.
Assuntos
DNA/química , Guanidinas/química , Modelos Moleculares , Conformação de Ácido NucleicoRESUMO
Chiral hairpin polyamides linked to a Hoechst 33258 analogue at the alpha-position of the hairpin turn amino acid (1,2) were synthesized on solid phase by adopting Fmoc and ivDde techniques. The DNA-binding properties of enantiomeric conjugates 1 and 2, and N-terminal linked conjugate 3 for 8-14bp sequences were determined by spectrofluorometric and thermal melting studies. Conjugates 1 and 2 recognize a 10bp sequence, while conjugate 3 recognizes a 9bp sequence. Interestingly, R-enantiomer 1 exhibited 10- to 30-fold higher binding affinities than S-enantiomer 2 for the DNA sequences studied. These binding differences were accounted for by molecular modeling studies, which revealed that the amide proton nearest to the chiral center in R-conjugate 1 is better positioned to form hydrogen bonds to the DNA bases, while S-conjugate 2 does not.