RNase E is an essential, multifunctional ribonuclease encoded in E. coli by the rne gene. Structural analysis indicates that the ribonucleolytic activity of this enzyme is conferred by rne-encoded polypeptide chains that (1) dimerize to form a catalytic site at the protein-protein interface, and (2) multimerize further to generate a tetrameric quaternary structure consisting of two dimerized Rne-peptide chains. We identify here a mutation in the Rne protein's catalytic region (E429G), as well as a bacterial cell wall peptidoglycan hydrolase (Amidase C [AmiC]), that selectively affect the specific activity of the RNase E enzyme on long RNA substrates, but not on short synthetic oligonucleotides, by enhancing enzyme multimerization. Unlike the increase in specific activity that accompanies concentration-induced multimerization, enhanced multimerization associated with either the E429G mutation or interaction of the Rne protein with AmiC is independent of the substrate's 5′ terminus phosphorylation state. Our findings reveal a previously unsuspected substrate length-dependent regulatory role for RNase E quaternary structure and identify cis-acting and trans-acting factors that mediate such regulation.
CITATION STYLE
Moore, C. J., Go, H., Shin, E., Ha, H. J., Song, S., Ha, N. C., … Lee, K. (2021). Substrate-dependent effects of quaternary structure on RNase E activity. Genes and Development, 35(3–4), 286–299. https://doi.org/10.1101/GAD.335828.119
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