Lactoferricin B inhibits bacterial macromolecular synthesis in ..
Derivatives having a wide range of para substituents are active; therefore, this part of the molecule is not involved in specific drug-target interactions. The propanediol moiety, the site of the D-threo configuration, is essential for activity. Acetylation of one or both hydroxyl groups inactivates the drug. Removal of the dichloroacetamido side chain virtually eliminates biological activity, although substitution by a number of groups does not render the drug inactive. Some substituents reduce activity against intact bacteria, but enhance the inhibition of cell-free protein synthesis (1). Apparently, these derivatives are not taken up by the bacterial cell as efficiently as the parent compound.
Inflating bacterial cells by increased protein synthesis
The highly conserved heat shock proteins (HSPs) are constitutively expressed and function as molecular chaperones which facilitate the synthesis and folding of proteins. They also participate in protein assembly, export, turn-over and regulation. Under stressful conditions such as heat shock, pH shift or hypoxia, increased expression of HSPs protect the cell by stabilizing unfolded proteins, giving the cell time to repair or re-synthesize damaged proteins. ELS offers a number of kits, antibodies, proteins, inhibitors and more reagents to study HSPs/chaperones, HSF’s, Grp’s, ERp’s, clusterin and other stress related molecules.
Fleming found that it was effective against many Gram positive bacteria in laboratory conditions, and he even used locally applied, crude preparations of this substance, from culture filtrates, to control eye infections.
Bacterial Protein Toxins - Textbook of Bacteriology
Chloramphenicol inhibits protein synthesis in bacterial extracts with varying potencies depending on the template employed. In particular, synthesis promoted by poly(U) is markedly more resistant to chloramphenicol than that promoted by poly(C) or poly (A) (8). Synthesis occurring with a natural mRNA (eg, MS2 phage RNA) is usually very sensitive to chloramphenicol. The precise reason for the template-dependence is not known. Chloramphenicol may inhibit poly(U)-dependent poly(Phe) synthesis less than it does the synthesis of other polypeptides because the structures of D-threo chloramphenicol and L-phenylalanine are similar (Fig. 3). Competition between these molecules during poly(Phe) synthesis may involve steric hindrance between their phenyl groups and, consequently, chloramphenicol may be chased from the ribosome. Nevertheless, this does not explain why the same template dependence is also observed with several other peptidyl-transferase inhibitors that differ chemically from chloramphenicol and, in particular, that do not have a phenyl group (e.g, the group B streptogramins and the macrolides). Further experiments are needed to elucidate this phenomenon in greater detail.
ribosomal proteins and inhibits protein synthesis.
They are active only against Gram-positive bacteria (which have a thick layer of peptidoglycan in the wall) and not against Gram-negative species, including many serious pathogens like Mycobacterium tuberculosis (the cause of tuberculosis).
Association of the hybrid proteins restores synthesis of ..
β-Galactosidases are widespread, in microorganisms, animals and plants. That from the Escherichia coli strain K12 has been particularly studied at Anfinsen's laboratory in connection with genetic experiments on gene regulation of protein synthesis. Craven, Steers and Anfinsen 1965). The enzyme has been reviewed in detail by Wallenfels and Weil (1972). Lactase may be used as a reagent for determining lactose in blood and other biological fluids.