RESUMO
A carbamate linked quenching group coupled with a pro-quinone methide reactive core provides an effective tool for studying enzyme function without problems associated with background fluorescence from unreacted probe. However, the relatively slow fragmentation of the carbamate linkage in such a strategy may cause problems of loss of signal or a decoupling of enzyme activity and labelling.
Assuntos
Arabidopsis/enzimologia , Carbamatos/química , Carboxilesterase/análise , Corantes Fluorescentes/química , Indolquinonas/química , Sequência de Aminoácidos , Fluorescência , Modelos Moleculares , Dados de Sequência Molecular , Alinhamento de SequênciaRESUMO
An emissive terbium complex has been conjugated to a C12 chain, Lys-Arg7, Arg7, a tetraguanidinium cation and human serum albumin; two-photon excitation at 720 nm facilitated microscopy studies revealing cell localisation profiles with the oligo-guanidinium conjugate localising in mitochondria but causing apoptotic cell death (IC(50)12 microM), the C12-amide complex giving rise to necrotic cell death in skin fibroblasts (IC50 8 microM) and the peptide conjugates and the methyl ester generating punctuate cytosolic intracellular distributions.
Assuntos
Arginina/química , Compartimento Celular/efeitos dos fármacos , Guanidina/química , Compostos Organometálicos/química , Térbio/química , Animais , Apoptose/efeitos dos fármacos , Relação Dose-Resposta a Droga , Fibroblastos/química , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Células HeLa , Humanos , Ligantes , Camundongos , Microscopia de Fluorescência/métodos , Mitocôndrias/química , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Conformação Molecular , Células NIH 3T3 , Compostos Organometálicos/farmacocinética , Peptídeos/química , Fótons , Albumina Sérica/química , Pele/química , Pele/citologia , EstereoisomerismoRESUMO
The intense luminescence of the new complex Ir(ppy)(2)(pybz) (1) within the cytoplasm of live cells can be discriminated from the fluorescence of an organic stain, solely on the basis of the emission timescale {pybzH = 2-pyridyl-benzimidazole}. The protonated form of 1 displays red-shifted emission, and may be implicated in a superior uptake compared to Ir(ppy)(3).
Assuntos
Irídio/química , Luminescência , Compostos Organometálicos/química , Animais , Células CHO , Cricetinae , Cricetulus , Microscopia de Fluorescência , Conformação Molecular , Compostos Organometálicos/síntese química , Fatores de TempoRESUMO
Excited state quenching by urate and ascorbate of selected europium and terbium(III) macrocyclic complexes has been assessed and related to the ease of complex visualisation by optical microscopy inside various living cells, e.g. CHO, COS and NIH 3T3. It is the relative insensitivity of certain sterically encumbered complexes to dynamic quenching by urate that favours their usage for in cellulo applications. Non-covalent binding of the complex by protein also shields the excited lanthanide(III) ion from collisional quenching; this effect is most marked for a cationic triamide complex, [Ln.1](3+), consistent with its ease of visualisation by luminescence microscopy.
Assuntos
Antioxidantes/metabolismo , Elementos da Série dos Lantanídeos/metabolismo , Animais , Linhagem Celular , Sobrevivência Celular , Chlorocebus aethiops , Cricetinae , Elementos da Série dos Lantanídeos/análise , Elementos da Série dos Lantanídeos/química , Compostos Macrocíclicos/química , Camundongos , Microscopia de Fluorescência , Sensibilidade e EspecificidadeRESUMO
Detailed analyses of the solution structure and exchange dynamics of two sets of homologous mono-amide triacetate lanthanide complexes (Ln = Eu, Gd) of cyclen have been undertaken. The complex [LnL1], bearing an N-linked CH2CH2NHCO-pyridyl moiety, forms mono-aqua (q = 1) species in solution and the Gd complex undergoes rapid water exchange (k(ex)= 11 x 10(7) s(-1), 298 K) as a result of the steric destabilisation of the Ln-water binding interaction. The homologous complex with a C-3 spacing chain, [LnL2], forms a q = 0 species.