目的探讨乙醇脱氢核酶ribox02与NAD^+、NADH特异性结合的位点以及结合力性质。方法通过选择性2-OH酰基化学探测法(selective 2-hydroxyl acylation analyzed by primer extension,SHAPE)探测ribox02的二级结构;利用等温滴定量热法(isoth...目的探讨乙醇脱氢核酶ribox02与NAD^+、NADH特异性结合的位点以及结合力性质。方法通过选择性2-OH酰基化学探测法(selective 2-hydroxyl acylation analyzed by primer extension,SHAPE)探测ribox02的二级结构;利用等温滴定量热法(isothermal titratio calorimetry,ITC)进一步测定ribox02与NADH、NAD^+的亲和力强度及作用力性质;通过紫外交联法精确定位NAD^+、NADH与ribox02 RNA的特异性结合位点。结果直接解析ribox02的二级结构,并发现核酶ribox02与NADH、NAD^+的相互作用力为范德华力或氢键作用,且ribox02与NADH的相互作用力较之与NAD^+更为强烈,ribox02与NADH、NAD^+的特异性结合位点为23G、24U、25U、38U、72U、73U、74U、75G和95G。结论通过ribox02的二级结构及其与NAD^+、NADH的相互作用揭示了核酶ribox02与NAD^+/NADH特异性结合位点以及结合力性质。展开更多
A simple device which incorporates three electrodes （working electrode, counter electrode and reference electrode） was constructed to be used currently in laboratories without elevated cost. It does not need more th...A simple device which incorporates three electrodes （working electrode, counter electrode and reference electrode） was constructed to be used currently in laboratories without elevated cost. It does not need more than 2 μL of electrolyte, sample or working solution, his support material is paper, and the working electrode which is based on carbon ink can incorporate enzymes and cofactors. To test this concept we started this investigation using the NADH/NAD＋ redox couple which is an onmipresent coenzyme in living systems but is also a challenge to electrochemistry. The paper sensor fabrication was simple, rapid and cheaper. NADH was incorporated in the carbon ink by mixing both and, this mixture was used to print the working electrode. The direct electrochemical system NADH/NAD＋ signal obtained, using this device, appeared at low potentials. A quasi-reversible diffusional redox process was achieved and regeneration of the NADH after oxidation was reached. This small paper device was not only used to study the redox process of NAD＋/NADH, but also its behavior in the presence of electroactive （ascorbic acid） and non-eletroactive species （glucose）.展开更多
The fluorescence properties of reduced nicotinamide adenine dinucleotide(NADH)and oxidizedflavoproteins(Fp)including flavin adenine dinucleotide(FAD)in the respiratory chain are sensitive indicators of intracellular m...The fluorescence properties of reduced nicotinamide adenine dinucleotide(NADH)and oxidizedflavoproteins(Fp)including flavin adenine dinucleotide(FAD)in the respiratory chain are sensitive indicators of intracellular metabolic states and have been applied to the studies of mitochondrial function with energy-linked processes.The redox scanner,a three-dimensional(3D)low temperature imager previously developed by Chance et al.,measures the in vivo metabolicproperties of tissue samples by acquiring fluorescence images of NADH and Fp.The redox ratios,i.e.Fp/(Fp+NADH)and NADH/(Fp+NADH),provided a sensitive index of the mitochondrialredox state and were determined based on relative signal intensity ratios.Here we report thefurther development of the redox scanning technique by using a calibration method to quantifythe nominal concentration of the fluorophores in tissues.The redox scanner exhibited very goodlinear response in the range of NADH concentration between 165–1318µM and Fp between90–720µM using snap-frozen solution standards.Tissue samples such as human tumor mousexenografts and various mouse organs were redox-scanned together with adjacent NADH and Fpstandards of known concentration at liquid nitrogen temperature.The nominal NADH and Fpconcentrations as well as the redox ratios in the tissue samples were quantified by normalizing the tissue NADH and Fp fluorescence signal to that of the snap-frozen solution standards.This calibration procedure allows comparing redox images obtained at different time,independent of instrument settings.The quantitative multi-slice redox images revealed heterogeneity inmitochondrial redox state in the tissues.展开更多
文摘目的探讨乙醇脱氢核酶ribox02与NAD^+、NADH特异性结合的位点以及结合力性质。方法通过选择性2-OH酰基化学探测法(selective 2-hydroxyl acylation analyzed by primer extension,SHAPE)探测ribox02的二级结构;利用等温滴定量热法(isothermal titratio calorimetry,ITC)进一步测定ribox02与NADH、NAD^+的亲和力强度及作用力性质;通过紫外交联法精确定位NAD^+、NADH与ribox02 RNA的特异性结合位点。结果直接解析ribox02的二级结构,并发现核酶ribox02与NADH、NAD^+的相互作用力为范德华力或氢键作用,且ribox02与NADH的相互作用力较之与NAD^+更为强烈,ribox02与NADH、NAD^+的特异性结合位点为23G、24U、25U、38U、72U、73U、74U、75G和95G。结论通过ribox02的二级结构及其与NAD^+、NADH的相互作用揭示了核酶ribox02与NAD^+/NADH特异性结合位点以及结合力性质。
文摘A simple device which incorporates three electrodes （working electrode, counter electrode and reference electrode） was constructed to be used currently in laboratories without elevated cost. It does not need more than 2 μL of electrolyte, sample or working solution, his support material is paper, and the working electrode which is based on carbon ink can incorporate enzymes and cofactors. To test this concept we started this investigation using the NADH/NAD＋ redox couple which is an onmipresent coenzyme in living systems but is also a challenge to electrochemistry. The paper sensor fabrication was simple, rapid and cheaper. NADH was incorporated in the carbon ink by mixing both and, this mixture was used to print the working electrode. The direct electrochemical system NADH/NAD＋ signal obtained, using this device, appeared at low potentials. A quasi-reversible diffusional redox process was achieved and regeneration of the NADH after oxidation was reached. This small paper device was not only used to study the redox process of NAD＋/NADH, but also its behavior in the presence of electroactive （ascorbic acid） and non-eletroactive species （glucose）.
基金the Susan G.Komen Foundation Grant KG081069(PI:L.Z.Li)an NIH supported research resource(P41-RR02305,PI:R.Reddy)+1 种基金the Network of Translational Research in Optical Imaging(NTROI)at the University of Pennsylvania(U54 CA105008,PI:W.S.El-Deiry)an NIH Grant UO1-CA105490(PI:L.A.Chodosh).
文摘The fluorescence properties of reduced nicotinamide adenine dinucleotide(NADH)and oxidizedflavoproteins(Fp)including flavin adenine dinucleotide(FAD)in the respiratory chain are sensitive indicators of intracellular metabolic states and have been applied to the studies of mitochondrial function with energy-linked processes.The redox scanner,a three-dimensional(3D)low temperature imager previously developed by Chance et al.,measures the in vivo metabolicproperties of tissue samples by acquiring fluorescence images of NADH and Fp.The redox ratios,i.e.Fp/(Fp+NADH)and NADH/(Fp+NADH),provided a sensitive index of the mitochondrialredox state and were determined based on relative signal intensity ratios.Here we report thefurther development of the redox scanning technique by using a calibration method to quantifythe nominal concentration of the fluorophores in tissues.The redox scanner exhibited very goodlinear response in the range of NADH concentration between 165–1318µM and Fp between90–720µM using snap-frozen solution standards.Tissue samples such as human tumor mousexenografts and various mouse organs were redox-scanned together with adjacent NADH and Fpstandards of known concentration at liquid nitrogen temperature.The nominal NADH and Fpconcentrations as well as the redox ratios in the tissue samples were quantified by normalizing the tissue NADH and Fp fluorescence signal to that of the snap-frozen solution standards.This calibration procedure allows comparing redox images obtained at different time,independent of instrument settings.The quantitative multi-slice redox images revealed heterogeneity inmitochondrial redox state in the tissues.
