Regulation of metE mRNA expression by FnrS small RNA in Salmonella enterica serovar Typhimurium.

Methionine is critical for variety of metabolic processes in biological organisms, acting as a precursor or intermediate for many final products. The last step for the synthesis of methionine is the methylation of homocysteine, which is catalyzed by MetE. Here, we use Salmonella enterica serovar Typhimurium LT2 to study the regulation of the metE gene by an anaerobically induced small non-coding RNA-FnrS, the expression of which is strictly dependent on the anaerobic regulator-FNR.

Specific regions of the SulA protein recognized and degraded by the ATP-dependent ClpYQ (HslUV) protease in Escherichia coli.

In Escherichia coli, ClpYQ (HslUV) is a two-component ATP-dependent protease, in which ClpQ is the peptidase subunit and ClpY is the ATPase and unfoldase. ClpY functions to recognize protein substrates, and denature and translocate the unfolded polypeptides into the proteolytic site of ClpQ for degradation. However, it is not clear how the natural substrates are recognized by the ClpYQ protease and the mechanism by which the substrates are selected, unfolded and translocated by ClpY into the interior site of ClpQ hexamers.