Protein biosynthesis bacterial

It has long been known that peptides of bacterial origin, such as N-formylat-ed oligopeptides, are potent activators of neutrophils. Bacterial protein biosynthesis is initiated by the codon AUG, which codes for polypeptide chains at the NH2 terminus to start with N-formylmethionine. However, very few mature bacterial proteins actually have this amino acid at the NH2 terminus because Af-formylmethionine is cleaved off by proteolytic processing. Sometimes just this amino acid is cleaved, but often several adjacent residues are also removed with it. These observations formed the basis for the chemical synthesis of a variety of N-formylated oligopeptides and an assessment of their ability to activate neutrophils in vitro. The most potent of these formylated peptides is TV-formylmethionyl-leucyl-phenylalanine (fMet-Leu-Phe). 

Bacterial protein biosynthesis is a cascade of events which manufacture chains of amino acids before they are folded into specific structures to carry out various biological functions. Protein biosynthesis is absolutely essential for the survival of prokaryotic and eukaryotic cells. Ribosomes, macromolecular complexes made up of proteins and RNA, participate in decoding the genetic message to synthesize both essential and nonessential proteins to carry out cellular functions. 

Antibiotics that block bacterial protein biosynthesis. Macrolides Target the 508 ribosome subunit. Tylosin, which is widely used in the livestock Clarithromycin (biaxin) Semisynthetic and has better intracellular penetration compared to earlier... 

Florfenicol targets the bacterial ribosome and inhibits bacterial protein biosynthesis. Acquired resistance has been reported, the forms being ribosomal mutations and reduction of the cell permeability. The molecular structure of florfenicol precludes the possibility that its toxicity is associated with idiosyncratic anemia. 

Macrolide antibiotics target the bacterial ribosome and inhibit the bacterial protein biosynthesis. Many gram-negative bacteria are inherently resistant to mac-rolides because their outer membrane is impermeable to macrolides. Several mechanisms of acquired resistance have been reported. In some cases, resistance is conferred by methylation of ribosomes by methylase enzymes, the genes of... 

Mode of Action. Elfamycins block bacterial protein biosynthesis at the level of elongation factor Tu (EF-Tu). 

More than 500 different representatives of the macrolide antibiotics are known, most of which are biologically active against Gram-positive bacteria, displaying a relatively low toxicity. Clinically used are erythromycin, oleandomycin, carbomycin and leucomycin (O Fig. 5). They act as inhibitors of the bacterial protein biosynthesis by binding to the 50S-ribosomal subunit. The synthesis of the two clinically important 16-membered ring macrolide antibiotics leucomycin A3 and carbomycin B could be started from D-glucose, which was chosen because it contained three of the required stereocenters [40]. 

Biochemical site of action of erythromycin Inhibits bacterial protein biosynthesis at the translocation step of translation... 

At normal doses, antibiotics do not bind to or interfere with the function of eukaryotic 803 ribosomal particles. The basis for the selective toxicity of these antibiotics is then apparent. Interference with bacterial protein biosynthesis prevents repair, cellular growth, and reproduction and can be clinically bacteriostatic or bactericidal. 

H02CC(H)(NH2)(CH2)3C(H)(NH2)C02H. M.p. at least 305"C. The o, l and meso forms are all isolated from hydrolysates of bacterial proteins. It is an intermediate in the biosynthesis of lysine in many bacteria. 

Protein polymers based on Lys-25 were prepared by recombinant DNA (rDNA) technology and bacterial protein expression. The main advantage of this approach is the ability to directly produce high molecular weight polypeptides of exact amino acid sequence with high fidelity as required for this investigation. In contrast to conventional polymer synthesis, protein biosynthesis proceeds with near-absolute control of macromolecular architecture, i.e., size, composition, sequence, topology, and stereochemistry. Biosynthetic polyfa-amino acids) can be considered as model uniform polymers and may possess unique structures and, hence, materials properties, as a consequence of their sequence specificity [11]. Protein biosynthesis affords an opportunity to completely specify the primary structure of the polypeptide repeat and analyze the effect of sequence and structural uniformity on the properties of the protein network. 

Protein synthesis is a central function in cellular physiology and is the primary target of many naturally occurring antibiotics and toxins. Except as noted, these antibiotics inhibit protein synthesis in bacteria. The differences between bacterial and eukaryotic protein synthesis, though in some cases subtle, are sufficient that most of the compounds discussed below are relatively harmless to eukaryotic cells. Natural selection has favored the evolution of compounds that exploit minor differences in order to affect bacterial systems selectively, such that these biochemical weapons are synthesized by some microorganisms and are extremely toxic to others. Because nearly every step in protein synthesis can be specifically inhibited by one antibiotic or another, antibiotics have become valuable tools in the study of protein biosynthesis. 

Inhibitions of protein synthesis were subsequently confirmed by chemical analyses for protein in growing bacterial cultures38, 39. Figure 439 shows the specific inhibition of protein biosynthesis by chloramphenicol in E. coli and the continuation of RNA ( ribose ) and DNA biosynthesis for an experimental period of 50 minutes. Similar results have been typically obtained with other inhibitors of protein biosynthesis. 

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