TheN l (s, r)/D l (s, r) approach and the standard equations of the inverse scattering problem

Weiss, J.

doi:10.1007/bf01698901

Cited by 23 publications

(37 citation statements)

References 7 publications

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“…This suggests that tobramycin is included in the ribosomal structure, like an endogenous polyamine [28].…”

Section: Discussionmentioning

confidence: 99%

Photo-Induced Labelling of Escherichia coli Ribosomes by a Tobramycin Analog

Tangy¹,

Capmau²

1983

Eur J Biochem

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An [3H]azidobenzyl derivative of tobramycin, a 4,6-disubstituted 2-deoxystreptamine aminoglycoside, has been synthesized, and its ability to label Escherichia coli 70-S ribosomes under photoactivation has been studied. Two concentrations of the photolabel, corresponding to the saturation of the two classes of tobramycin sites on the ribosomes, were used. The results show that, at high antibiotic concentrations which induce maximal misreading during protein synthesis, most of the ribosomal proteins are labelled. At low antibiotic concentration, which results in the saturation of the first-class sites, a few proteins of both subunits are labelled, including L6, S4, S 5, and, to a lesser extent, L2, L13 and S18. The 30-S subunit is, on the whole, labelled more efficiently than the 50-S subunit.In spite of the great similarity in structure of aminoglycosides, recent studies have suggested that there are differences in their mode of action at the level of the bacterial ribosomes. Whereas the facts seem clear as to the differences which exist between aminoglycosides containing the streptidine residue (streptomycin) and those containing 2-deoxystreptamine [I -51 the differences between the aminoglycosides derived from kanosamine (kanamycin, tobramycin) and those derived from garosamine (gentamicin, sisomicin) are seldom shown. It is clear, however, that these two families of closely related antibiotics behave differently in relation to the biosynthesis of proteins [I] and their binding on bacterial ribosomes [5, 71 (and Moukaddem, Tangy and Le Goffic, unpublished results).We have shown that tobramycin interacts on two classes of sites of the 70-S ribosome [4, 51: the first class, of high affinity (Kd = 0.2 pM), is saturated at a low concentration, which is also responsible for a significant inhibition of R17 mRNA translation [8, 91; the second class, of lower affinity (Kd = 10 pM), can accept a large number of antibiotic molecules. The high concentrations necessary to saturate this latter family of sites suggest that the conformational modifications which they induce on both the 50-S and the 3 0 4 subunits are responsible for the misreading. It should be noticed that such aminoglycoside concentrations also inhibit the dissociation of ribosomes into their subunits [lo].It seemed, therefore, of interest to identify the ribosomal proteins involved with these antibiotics in order to determine whether the latter have a specific action on protein synthesis or whether they simply modify the conformation of the ribosomes in a non-specific, yet efficient, way.In this communication, we present the results of affinity labelling experiments using Escherichia coli ribosomes, and a photoreactivable derivative of tobramycin.

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“…This suggests that tobramycin is included in the ribosomal structure, like an endogenous polyamine [28].…”

Section: Discussionmentioning

confidence: 99%

Photo-Induced Labelling of Escherichia coli Ribosomes by a Tobramycin Analog

Tangy¹,

Capmau²

1983

Eur J Biochem

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“…Previous attempts to increase membrane electronegativity either by blockade of cationic groups or the introduction of anionic ligands have been largely inconclusive (17,18). The one exception is glutaraldehyde, a fixative, which increases the rate of human red blood cell electrophoretic mobility by 14% (19). This agent, however, seriously disrupts membrane architecture (20) and subsequently makes it difficult to evaluate the functional role of the membrane surface charge.…”

Section: )mentioning

confidence: 98%

Effect of Cyanate on Erythrocyte Membrane Surface Charge

Durocher

Glader

Conrad

1973

Experimental Biology and Medicine

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“…In this respect, the reader is referred to a review on coronavirus polyprotein processing. 26 RNA Polymerase Gene Function. There have been occasional reports of RNA-dependent RNA polymerase activity in subcellular fractions of coronavirus-infected cells or in coronavirus-infected cells permeabilized with lysolecithin.…”

Section: Biochemical Analysismentioning

confidence: 99%

[5] Characterization of coronavirus RNA polymerase gene products

Herold¹,

Siddell²,

Ziebuhr³

1996

Methods in Enzymology

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IntroductionThe coronavirus RNA polymerase gene encompasses about 20,000 nucleotides and comprises two large open reading frames (ORFs), ORF la and ORF lb, that overlap in the (-1) reading frame by approximately 40-80 nucleotides. Together, these two ORFs have the potential to encode polypeptides with a total molecular mass of 750,000-800,000. In vitro studies suggest that the downstream ORF lb is expressed by a mechanism involving (-1) ribosomal frameshifting, mediated by a "slippery" sequence and a tertiary structure, the RNA pseudoknot. These elements are positioned in the RNA polymerase mRNA (which is equivalent to the viral genomic RNA) in the region of the ORF la/ORF lb overlap. 1-6Genetic analysis of coronavirus temperature-sensitive (ts) mutants, defective in RNA synthesis at the restrictive temperature, has identified a number of distinct viral functions required for the replication and transcription of genomic and subgenomic RNAs. Characterization of these mutants by recombination and sequence analysis has allowed these functions to be located and ordered within the RNA polymerase gene. Moreover, because the complementation frequencies of these mutants are indicative of intergenic rather than intragenic complementation, they provide clear evidence for the activity of proteinases that process the primary translation product(s) of the polymerase gene into smaller, functional polypeptides. 7-1°

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TheN l (s, r)/D l (s, r) approach and the standard equations of the inverse scattering problem

Cited by 23 publications

References 7 publications

Photo-Induced Labelling of Escherichia coli Ribosomes by a Tobramycin Analog

Photo-Induced Labelling of Escherichia coli Ribosomes by a Tobramycin Analog

Effect of Cyanate on Erythrocyte Membrane Surface Charge

[5] Characterization of coronavirus RNA polymerase gene products

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