Format

Send to

Choose Destination
Structure. 2014 May 6;22(5):707-18. doi: 10.1016/j.str.2014.02.012. Epub 2014 Mar 20.

CdiA from Enterobacter cloacae delivers a toxic ribosomal RNase into target bacteria.

Author information

1
Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106-9625, USA.
2
Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA 92697, USA.
3
Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106-9625, USA; Biomolecular Science and Engineering Program, University of California, Santa Barbara, Santa Barbara, CA 93106-9625, USA.
4
Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA 92697, USA; Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, CA 92697, USA.
5
Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106-9625, USA; Biomolecular Science and Engineering Program, University of California, Santa Barbara, Santa Barbara, CA 93106-9625, USA. Electronic address: chayes@lifesci.ucsb.edu.

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.

PMID:
24657090
PMCID:
PMC4016183
DOI:
10.1016/j.str.2014.02.012
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Elsevier Science Icon for PubMed Central
Loading ...
Support Center