RESUMEN
A new ruthenium complex with a dppz-like ligand pyidppz, [Ru(bpy)2(pyidppz)](2+) (pyidppz = 2-(pyridine-2-yl)imidazo-[4,5-b]dipyrido-[3,2-a:2',3'-c]phenazine) has been synthesized and characterized by ES-MS, elemental analysis, (1)H NMR. Intercalative mode of the complex bound to calf thymus DNA has been supported by different spectroscopic methods and viscosity measurements. The introduction of phenazine unit may be one of the main reasons for the weak emission of Ru(II) complex in aqueous solution. Under irradiation, this complex can efficiently cleave DNA. And the photocleavage reaction of the complex is found to be inhibited in the presence of singlet oxygen scavenger. Topoisomerase inhibition and DNA strand passage assay demonstrated that [Ru(bpy)2(pyidppz)](2+) and its parent complex [Ru(bpy)2(pyip)](2+) (pyip = 2-(pyridine-2-yl)imidazo[4,5-f][1,10]phenanthroline) can act as efficient catalytic inhibitor of DNA topoisomerase I.
Asunto(s)
División del ADN/efectos de los fármacos , ADN/química , Luz , Compuestos Organometálicos/química , Compuestos Organometálicos/farmacología , Fenazinas/química , Rutenio/química , Animales , Bovinos , ADN/metabolismo , Ligandos , Compuestos Organometálicos/metabolismo , Inhibidores de Topoisomerasa I/química , Inhibidores de Topoisomerasa I/metabolismo , Inhibidores de Topoisomerasa I/farmacologíaRESUMEN
A new ligand mhcip (mhcip=2-(4-methyl-7-hydroxyl-8-coumarinyl)imidazo[4,5-f]-[1,10]phenanthroline) and its ruthenium complexes, [Ru(L)2mhcip](2+) (L=bpy (2,2'-bipyridine), phen (1,10-phenanthroline)), have been synthesized and characterized. The introduction of coumarin ring may play an important role in the strong fluorescence of the complexes. Intercalative binding mode between both complexes and CT-DNA was determined by UV-visible spectroscopy, fluorescence spectroscopy and viscosity measurements. The two complexes show efficient DNA photocleavage under irradiation at 365 nm. The cycling of light switch off and on has been achieved for both complexes through the introduction of Cu(2+) and EDTA in the absence or presence of DNA.
Asunto(s)
Cumarinas/farmacología , ADN/metabolismo , Sustancias Intercalantes/farmacología , Compuestos Organometálicos/farmacología , Rutenio/farmacología , 2,2'-Dipiridil/química , 2,2'-Dipiridil/farmacología , Animales , Bovinos , Cumarinas/química , División del ADN/efectos de los fármacos , División del ADN/efectos de la radiación , Sustancias Intercalantes/química , Luz , Compuestos Organometálicos/química , Fenantrolinas/química , Fenantrolinas/farmacología , Fotólisis/efectos de los fármacos , Fotólisis/efectos de la radiación , Rutenio/químicaRESUMEN
The 1-deoxy-D-xylulose-5-phosphate synthase (DXS) enzyme has been characterized in other species, but not in the genus Babesia, which causes major losses in the livestock industries worldwide. Therefore, we isolated, cloned and expressed the wild-type B. bovis dxs cDNA in Escherichia coli and evaluated its enzymatic activity in vitro. DNA sequence analysis revealed an open reading frame of 2061 bp capable of encoding a polypeptide of 686 amino acid residues with a calculated isoelectric point of pH 6.93 and a molecular mass of 75 kDa. The expressed soluble recombinant fusion DXS protein was approximately 78 kDa, which is similar to the native enzyme identified from the parasite merozoite using anti-rDXS serum. The recombinant fusion DXS enzyme exhibited Km values of 380 ± 46 µM and 790 ± 52 µM for D,L-glyceraldehyde 3-phosphate and pyruvate, respectively. In this work, we present the first cloning, expression and characterization of DXS enzyme from B. bovis.
Asunto(s)
Babesia bovis/enzimología , Regulación Enzimológica de la Expresión Génica/fisiología , Proteínas Protozoarias/metabolismo , Transferasas/metabolismo , Secuencia de Aminoácidos , Clonación Molecular , Biología Computacional , Datos de Secuencia Molecular , Proteínas Protozoarias/genética , Transferasas/genéticaRESUMEN
Two novel Ru(II) complexes [Ru(bpy)(2)(pyip)](2+)1 and [Ru(phen)(2)(pyip)](2+)2 (bpy=2,2'-bipyridine; phen=1,10-phenanthroline; pyip=2-(pyridine-2-yl)imidazo-[4,5-f][1,10]-phenanthroline), have been synthesized and characterized by elemental analysis, ES-MS, (1)H NMR, UV-Vis. The DNA-binding behaviors of both complexes were studied by spectroscopic methods and viscosity measurements. The results indicate that the two complexes can bind to CT-DNA in an intercalative mode, and also show that these two Ru(II) complexes can promote the photocleavage of pBR322 DNA. In addition, In the presence of Co(2+), the emission of DNA-[Ru(L)(2)pyip](2+) can be quenched, which exhibited the DNA "light switch" properties.