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Ribosome E. coli

FIG. 11.7 Loss of magnesium from ribosomes E. coli) in presence of streptomycin (pH 7.4). (Choi and Carr, 1968.)... [Pg.437]

Macrolide, lincosamide and streptogramin B resistance (MLSb phenotype) can be linked to specific nucleotide changes within the 23 S rRNA of the large ribosomal subunit, mainly at position A2058 or neighbouring bases (E. coli numbering). This is the... [Pg.773]

In recent years a number of in vitro studies have shown that the presence of Met(O) residues in a wide variety of proteins causes loss of biological activity. Table 2 lists some proteins which have been demonstrated to lose activity when specific Met residues are oxidized in vitro. Two of these proteins, E. coli ribosomal protein LI 2 and mammalian a-1-PI, have been studied extensively and will be discussed in detail. [Pg.857]

Not only eukaryotic cells but also bacteria have successfully been targeted by PNA anhsense strategies. Thus it has been shown that PNA complementary to ribosomal RNA or mRNA encoding an essential fatty acid biosynthesis protein, effectively kills E. coli. Furthermore, it has been shown that PNA directed to the start codon of the y -lactamase gene re-sensitized otherwise resistant E. coli to the antibiohc ampiciUin [64—66]. Conjugating a simple transporter peptide to the PNA increased the potency significantly, and an even more potent antibacterial PNA... [Pg.160]

What could be the signal for the induction of the cold shock proteins It has been observed that shifting E. coli cells from 37 to 5 °C results in an accumulation of 70S monosomes with a concomitant decrease in the number of polysomes [129]. Further, it has been shown that a cold shock response is induced when ribosomal function is inhibited, e.g. by cold-sensitive ribosomal mutations [121] or by certain antibiotics such as chloramphenicol [94]. These data indicate that the physiological signal for the induction of the cold shock response is inhibition of translation caused by the abrupt shift to lower temperature. Then, the cold shock proteins RbfA, CsdA and IF2 associate with the 70S ribosomes to convert the cold-sensitive nontranslatable ribosomes into cold-resistant translatable ribosomes. This in turn results in an increase in cellular protein synthesis and growth of the cells. [Pg.27]

Finally, to produce the structural and functional devices of the cell, polypeptides are synthesized by ribosomal translation of the mRNA. The supramolecular complex of the E. coli ribosome consists of 52 protein and three RNA molecules. The power of programmed molecular recognition is impressively demonstrated by the fact that aU of the individual 55 ribosomal building blocks spontaneously assemble to form the functional supramolecular complex by means of noncovalent interactions. The ribosome contains two subunits, the 308 subunit, with a molecular weight of about 930 kDa, and the 1590-kDa 50S subunit, forming particles of about 25-nm diameter. The resolution of the well-defined three-dimensional structure of the ribosome and the exact topographical constitution of its components are still under active investigation. Nevertheless, the localization of the multiple enzymatic domains, e.g., the peptidyl transferase, are well known, and thus the fundamental functions of the entire supramolecular machine is understood [24]. [Pg.395]

Three ofher mechanisms of chloramphenicol resisfance have been described. Firsf, a fransposon-encoded chloramphenicol efflux protein has been idenfified in E. coli. Second, some bacterial sfrains have been found to possess drug-resisfanf ribosomes, and fhird, low level resisfance can arise by chromosomal mufafions which reduce fhe amounf ofporins and fherefore impair uptake. This last mechanism is essentially that described for the AG AC antibiotics. [Pg.190]

CpCpApCpCpA and this hexanucleotide has been prepared from appropriately protected trinucleotides using a sulphonyl chloride as condensing agent.2 (3 )-0-Glycyl esters of Cpl and dCpA have been prepared as potential substrates of ribosomal peptidyl transferase. While the glycyl ester of Cpl released the polypeptide chain from polylysyl-tRNA in a ribosomal system from E. coli, the dCpA derivative showed little activity. [Pg.131]

In E. Coli bacterial lysates, the proteome (i.e., the full array of proteins produced) was analyzed by isoelectric focusing and mass spectrometry.97 A comparison of capillary electrophoretic separation and slab gel separation of a recombinant monoclonal antibody demonstrated that the precision, robustness, speed, and ease-of-use of CE were superior.98 Seventy-five proteins from the yeast ribosome were analyzed and identified by capillary electrophoresis coupled with MS/MS tandem mass spectrometry.99 Heavy-chain C-terminal variants of the anti-tumor necrosis factor antibody DE7 have been separated on capillary isoelectric focusing.100 Isoforms differing by about 0.1 pi units represented antibodies with 0,1 or 2 C-terminal lysines. [Pg.435]

Pearson and coworkers investigated several antibiotic-resistant strains of E. coli in an elegant and thorough study. Using a combination of MALDI-TOF and electrospray LC-MS they found that varying subtle mutations in ribosomal proteins occur in different strains that are resistant to various anti-... [Pg.196]


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See also in sourсe #XX -- [ Pg.439 , Pg.453 ]




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