| Literature DB >> 24657090 |
Christina M Beck1, Robert P Morse2, David A Cunningham1, Angelina Iniguez2, David A Low3, Celia W Goulding4, Christopher S Hayes5.
Abstract
Contact-dependent growth inhibition (CDI) is one mechanism of inter-bacterial competition. CDI(+) cells export large CdiA effector proteins, which carry a variety of C-terminal toxin domains (CdiA-CT). CdiA-CT toxins are specifically neutralized by cognate CdiI immunity proteins to protect toxin-producing cells from autoinhibition. Here, we use structure determination to elucidate the activity of a CDI toxin from Enterobacter cloacae (ECL). The structure of CdiA-CT(ECL) resembles the C-terminal nuclease domain of colicin E3, which cleaves 16S ribosomal RNA to disrupt protein synthesis. In accord with this structural homology, we show that CdiA-CT(ECL) uses the same nuclease activity to inhibit bacterial growth. Surprisingly, although colicin E3 and CdiA(ECL) carry equivalent toxin domains, the corresponding immunity proteins are unrelated in sequence, structure, and toxin-binding site. Together, these findings reveal unexpected diversity among 16S rRNases and suggest that these nucleases are robust and versatile payloads for a variety of toxin-delivery platforms.Entities:
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Year: 2014 PMID： 24657090 PMCID： PMC4016183 DOI： 10.1016/j.str.2014.02.012
Source DB: PubMed Journal: Structure ISSN： 0969-2126 Impact factor: 5.006