Sensory adaptation and chemotaxis by Escherichia coli require a specific pentapeptide at the chemoreceptor carboxyl terminus. This sequence binds the two enzymes of receptor adaptational modification, enhancing catalysis, but with different binding features and mechanisms. We investigated the relative importance of each pentapeptide side chain for the two enhancing interactions.
View Article and Find Full Text PDFHeat shock protein 90 (Hsp90) is critical for the maturation of numerous client proteins, many of which are involved in cellular transformation and oncogenesis. The ansamycins, geldanamycin (GA) and its derivative, 17-allylaminogeldanamycin (17-AAG), inhibit Hsp90. As such, the prototypical Hsp90 inhibitor, 17-AAG, has advanced into clinical oncology trials.
View Article and Find Full Text PDFSensory adaptation in bacterial chemotaxis is mediated by covalent modification of chemoreceptors. Specific glutamyl residues are methylated and demethylated in reactions catalyzed by methyltransferase CheR and methylesterase CheB. In Escherichia coli and Salmonella enterica serovar typhimurium, efficient adaptational modification by either enzyme is dependent on a conserved pentapeptide sequence at the chemoreceptor carboxyl terminus, a position distant from the sites of modification.
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