title: Positive allosteric feedback regulation of the stringent response enzyme RelA by its product.
abstract: During the stringent response, Escherichia coli enzyme RelA produces the ppGpp alarmone, which in turn regulates transcription, translation and replication. We show that ppGpp dramatically increases the turnover rate of its own ribosome-dependent synthesis by RelA, resulting in direct positive regulation of an enzyme by its product. Positive allosteric regulation therefore constitutes a new mechanism of enzyme activation. By integrating the output of individual RelA molecules and ppGpp degradation pathways, this regulatory circuit contributes to a fast and coordinated transition to stringency.
authors: Biomedical Technology, Institute of Technology, University of Tartu, Nooruse 1, Tartu 51017, Estonia.
authors: Viktoriya
authors: V
authors: Shyp
authors: Stoyan
authors: S
authors: Tankov
authors: Andrey
authors: A
authors: Ermakov
authors: Pavel
authors: P
authors: Kudrin
authors: Brian P
authors: BP
authors: English
authors: Måns
authors: M
authors: Ehrenberg
authors: Tanel
authors: T
authors: Tenson
authors: Johan
authors: J
authors: Elf
authors: Vasili
authors: V
authors: Hauryliuk
mesh_terms: D000494:Allosteric Regulation; D004789:Enzyme Activation; D004926:Escherichia coli / Q000201:enzymology* / Q000378:metabolism; D006159:Guanosine Tetraphosphate / Q000096:biosynthesis*; D008025:Ligases / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism
chemical_list: D006159:Guanosine Tetraphosphate; D008025:Ligases; C028812:guanosine 3',5'-polyphosphate synthetases