Structural basis for microcin C7 inactivation by the MccE acetyltransferase

Vinayak Agarwal, Anastasiya Metlitskaya, Konstantin Severinov, Satish K. Nair

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)

Abstract

The antibiotic microcin C7 (McC) acts as a bacteriocide by inhibiting aspartyl-tRNA synthetase and stalling the protein translation machinery. McC is synthesized as a heptapeptide-nucleotide conjugate, which is processed by cellular peptidases within target strains to yield the biologically active compound. As unwanted processing of intact McCcan result in self-toxicity, producing strains utilize multiple mechanisms for autoimmunity against processed McC. We have shown previously that the mccE gene within the biosynthetic cluster can inactivate processed McC by acetylating the antibiotic. Here, we present the characterization of this acetylation mechanism through biochemical and structural biological studies of the MccE acetyltransferase domain (MccEAcTase). We have also determined five crystal structures of the MccE-acetyl-CoA complex with bound substrates, inhibitor, and reaction product. The structural data reveal an unexpected mode of substrate recognition through π-stacking interactions similar to those found in cap-binding proteins and nucleotidyltransferases. These studies provide a rationale for the observation that MccEAcTase can detoxify a range of aminoacylnucleotides, including those that are structurally distinct from microcin C7.

Original languageEnglish
Pages (from-to)21295-21303
Number of pages9
JournalJournal of Biological Chemistry
Volume286
Issue number24
DOIs
Publication statusPublished - 17 Jun 2011
Externally publishedYes

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