Kinetics of conformational changes in tRNAPhe (yeast) as studied by the fluorescence of the y-base and of formycin substituted for the 3'-terminal adenine

Coutts, Stephen M.; Riesner, Detlev; Römer, R.; Rabl, Cad R.; Maaß, G.

doi:10.1016/0301-4622(75)80020-2

Cited by 58 publications

(41 citation statements)

References 30 publications

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“…For fast temperaturejumps the Eigen-DeMaeyer technique was used. The particular design of our instrument was described in detail in [9]. Computer calculations were performed on a Cyber 76 and a Prime 300.…”

Section: Methodsmentioning

confidence: 99%

Common structural features of different viroids: serial arrangement of double helical sections and internal loops

et al. 1978

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The thermodynamic parameters of five different highly purified viroid "species" were determined by applying UV-absorption melting analysis and temperature jump methods. Their thermal denaturation proved to be a highly cooperative process with midpoint-temperatures (Tm) between 48.5 and 510C in 0.01 M sodium cacodylate, 1 mM EDTA, pH 6.8. The values of the apparent reaction enthalpies of the different viroid species range between 3,140 and 3,770 kJ/mol. Although the cooperativity is as high as found in homogeneous RNA double helices the Tm-value of viroid melting is more than 300C lower than in the homogeneous RNA. In order to explain this deviation, melting curves were simulated for different models of the secondary strtrcture of viroids using literature values of the thermodynamic parameters of nucleic acids. Our calculations show that the following refinement of our earlier model is in complete accordance with the experimental data: In their native conformation viroids exist as an extended rodlike structure characterized by a series of double helical sections and internal loops. In the different viroid species 250-300 nucleotides out of total 350 nucleotides are needed to interprete the thermodynamic behaviour.

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Section: Methodsmentioning

confidence: 99%

Common structural features of different viroids: serial arrangement of double helical sections and internal loops

et al. 1978

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“…The substantially greater fraction of MT tRNA Gln that can be kinetically trapped in an inactive conformation (Fig. 2) must arise from sequence differences compared to the E. coli tRNA Gln and provides another example demonstrating that the detailed folding properties of individual tRNA species are highly distinct (Hilbers et al 1973;Coutts et al 1975).…”

Section: Application To the Study Of Trna Modificationmentioning

confidence: 98%

“…Relaxation kinetics and nuclear magnetic resonance suggested that heat-denatured, inactive tRNAs possess an altered tertiary conformation that is not aminoacylable by aaRS Crothers et al 1974;Bina-Stein et al 1976;Hilbers et al 1976). Temperature-dependent unfolding occurs through distinct, sequence-dependent ensembles in different tRNA species: The order of melting of the tertiary core and four helical arms of the cloverleaf is not fully conserved (Hilbers et al 1973;Coutts et al 1975).…”

Section: Introductionmentioning

confidence: 99%

Kinetics of tRNA folding monitored by aminoacylation

Bhaskaran

Rodríguez-Hernández²,

Perona³

2012

RNA

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We describe a strategy for tracking Mg 2+ -initiated folding of 32 P-labeled tRNA molecules to their native structures based on the capacity for aminoacylation by the cognate aminoacyl-tRNA synthetase enzyme. The approach directly links folding to function, paralleling a common strategy used to study the folding of catalytic RNAs. Incubation of unfolded tRNA with magnesium ions, followed by the addition of aminoacyl-tRNA synthetase and further incubation, yields a rapid burst of aminoacyl-tRNA formation corresponding to the prefolded tRNA fraction. A subsequent slower increase in product formation monitors continued folding in the presence of the enzyme. Further analysis reveals the presence of a parallel fraction of tRNA that folds more rapidly than the majority of the population. The application of the approach to study the influence of post-transcriptional modifications in folding of Escherichia coli tRNA 1 Gln reveals that the modified bases increase the folding rate but do not affect either the equilibrium between properly folded and misfolded states or the folding pathway. This assay allows the use of 32 P-labeled tRNA in integrated studies combining folding, post-transcriptional processing, and aminoacylation reactions.

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“…The temperature-jump apparatus was equipped with a fluorescence detection device as described by Coutts et al [48] (,Iex = 488 nm, ,Ie, = 530 nm). All measurements were performed at 25 "C in 0.1 M NaC1,0.02 M potassium phosphate pH 7.4.…”

Section: Kinetic Measurementsmentioning

confidence: 99%

Equilibrium, kinetic and photoaffinity labeling studies of daunomycin binding to P‐glycoprotein‐containing membranes of multidrug‐resistant Chinese hamster ovary cells

Busche

Tümmler

Cano‐Gauci

et al. 1989

European Journal of Biochemistry

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The binding of daunomycin and its Bolton-Hunter derivative iodomycin to plasma membranes isolated from mukidrug-resistant Chinese hamster ovary cells (CHO B30) and their drug-sensitive parents (Bl) was investigated. The thermodynamics and kinetics of equilibrium binding monitored by fluorescence titrations and temperaturejump relaxation spectrometry were compared with the specificity of covalent photolabeling with [3H]daunomycin and [1251]iodomycin. The facts that the uptake of anthracycline from aqueous solution into the CHO membranes was not accompanied by any substantial increase of fluorescence anisotropy nor by any spectral shift of the fluorescence emission spectrum and that the partition ratio into the membrane was 20-30-fold higher when compared to a lecithin bilayer, provided evidence that the non-covalent drug binding sites are constituted by polar protein domains without any substantial contribution from the surrounding lipids. Photoaffinity labeling with nanomolar concentrations of anthracycline and equilibrium binding curves independently showed that a 1 SO -170-kDa plasma membrane glycoprotein (P-glycoprotein), whose overexpression is the major difference between B1 and B30 membranes, provides the binding sites of highest affinity for daunomycin and iodomycin ( K z 4 x lo7 M-'). Comparison of photolabeling and equilibrium data suggested that the same binding sites on P-glycoprotein were most probably being monitored. The photolabeling of P-glycoprotein by iodomycin was inhibited in a dosedependent manner by other compounds to which multidrug-resistant cells are either resistant or collaterally sensitive with the following orders of effectiveness : vinblastine > verapamil > nitrendipine > daunomycin $ colchicine. Temperature-jump experiments covering the time range of 1 ps to 1 s revealed a single concentrationdependent relaxation time of 10-30 ps. The association of daunomycin with its binding sites in the membranes was found to be a diffusion-controlled process with k,, rates of 2-4 x lo9 M -l s-' . Therefore, the selectivity of drug binding was entirely reflected in the dissociation rates.Multidrug resistance in mammalian cell lines is a complex phenotype of cross-resistance to a wide range of amphiphilic compounds which have no obvious structural or functional similarities [l -51. Mutant lines of Chinese hamster ovary cells (CHO), selected by exposure to a single cytotoxic agent like daunomycin or colchicine, acquired cross-resistance to Vinca alkaloids, anthracyclines, macrolides, taxol and puromycin and became collaterally sensitive to steroids, local anesthetics and certain calcium-channel blockers [6]. The multidrug-resistance phenotype results from a decreased intracellular accumulation of drug which probably involves a complex set of processes including drug uptake, drug efflux, drug metabolism, and binding to intracellular sites [4, 7 - and human cells, P-glycoprotein (mdr) genes comprise a small multigene family [l 5 , 17 -221. Transfection of a full-length cDNA for a single mouse mdr or...

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Kinetics of conformational changes in tRNAPhe (yeast) as studied by the fluorescence of the y-base and of formycin substituted for the 3'-terminal adenine

Cited by 58 publications

References 30 publications

Common structural features of different viroids: serial arrangement of double helical sections and internal loops

Common structural features of different viroids: serial arrangement of double helical sections and internal loops

Kinetics of tRNA folding monitored by aminoacylation

Equilibrium, kinetic and photoaffinity labeling studies of daunomycin binding to P‐glycoprotein‐containing membranes of multidrug‐resistant Chinese hamster ovary cells

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