9.B.36.1.1
The acid resistance 6 TMS HdeD protein of 190 aas. The yhiD and hdeD gene products participate in an acid resistance mechanism exhibited only at high cell densities (Mates et al. 2007). H-NS directly controls expression of the hedD gene (Krin et al. 2010).  Both small RNAs, CyaR and RprA, interact with the 5'-UTR of hdeD mRNA, and binding to the RBS of hdeD, interfers with translational initiation. Lalaouna et al. 2018 identified an A/U-rich motif on hdeD, which is bound by the RNA chaperone Hfq. The results indicate that binding of this motif by Hfq is required for CyaR-induced degradation of hdeD mRNA, and two molecules of RprA must bind the 5'-UTR of hdeD to block translation initiation. While both CyaR and RprA sRNAs bind to the same motif on the hdeD mRNA, RprA solely acts at the translational level, leaving the target RNA intact (Lalaouna et al. 2018).