RRC ID 35371
Author Payoe R, Fahlman RP.
Title Dependence of RelA-mediated (p)ppGpp formation on tRNA identity.
Journal Biochemistry
Abstract The bacterial stringent response is a cellular response to amino acid limitations and is characterized by the accumulation of the alarmone polyphosphate guanosine ((p)ppGpp). A key molecular event leading to (p)ppGpp synthesis is the binding of a deacylated tRNA to the vacant A-Site of a ribosome. The resulting ribosomal complex is recognized by and activates RelA, the (p)ppGpp synthetase. Activated RelA catalyzes (p)ppGpp formation until the deacylated tRNA passively dissociates from the ribosomal A-Site. In this report, we have investigated a novel role for the identity of A-Site bound tRNA in RelA-mediated (p)ppGpp synthesis. A comparison in the stimulation of RelA activity was made using ribosome complexes with either a tightly or weakly binding deacylated tRNA occupying the A-Site. In vitro analysis reveals that ribosome complexes formed with tight binding tRNA(Val) stimulate RelA activity at lower concentrations than that required for ribosome complexes formed with the weaker binding tRNA(Phe). The data suggest that the recovery from the stringent response may be dependent on the identity of the amino acid that was initially limiting for the bacteria.
Volume 50(15)
Pages 3075-83
Published 2011-4-19
DOI 10.1021/bi1015309
PMID 21410133
MeSH Base Sequence Cell Line Enzyme Activation Escherichia coli / enzymology Escherichia coli / metabolism Guanosine Pentaphosphate / biosynthesis* Kinetics Ligases / metabolism* RNA, Transfer / genetics RNA, Transfer / metabolism* Ribosomal Proteins / metabolism
IF 2.997
Times Cited 6
Prokaryotes E. coli JW2755(ASKA)