Publication Abstract from PubMed
Bacteria encounter environmental stresses that regulate a gene expression program required for adaptation and survival. Here, we report the 1.8 Angstrom crystal structure of the E. coli toxin-antitoxin complex YafQ-(DinJ)2-YafQ, a key component of the stress response. The antitoxin DinJ dimer adopts a ribbon-helix-helix motif required for transcriptional autorepression while toxin YafQ contains a microbial RNase fold whose proposed active site is concealed by DinJ binding. Contrary to previous reports, our studies indicate that equivalent levels of transcriptional repression occur by direct interaction of either YafQ-(DinJ)2-YafQ or a DinJ dimer at a single inverted repeat of its recognition sequence which overlaps with the -10 promoter region. Surprisingly multiple YafQ-(DinJ)2-YafQ complexes binding to the operator region do not appear to amplify the extent of repression. Our results suggest an alternative model for transcriptional autorepression that may be novel to DinJ-YafQ.
Mechanisms of Toxin Inhibition and Transcriptional Repression by E. coli DinJ-YafQ.,Ruangprasert A, Maehigashi T, Miles SJ, Giridharan N, Liu JX, Dunham CM J Biol Chem. 2014 Jun 4. pii: jbc.M114.573006. PMID:24898247[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
