ε, a new subunit of RNA polymerase found in gram-positive bacteria

Andrew N. Keller, Xiao Yang, Jana Wiedermannova´, Olivier Delumeau, Libor Krasny, Peter J. Lewis

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21 Citations (Scopus)

Abstract

RNA polymerase in bacteria is a multisubunit protein complex that is essential for gene expression. We have identified a new subunit of RNA polymerase present in the high-A+T Firmicutes phylum of Gram-positive bacteria and have named it ε. Previously ε had been identified as a small protein (ω1) that copurified with RNA polymerase. We have solved the structure of ε by X-ray crystallography and show that it is not an ω subunit. Rather, ε bears remarkable similarity to the Gp2 family of phage proteins involved in the inhibition of host cell transcription following infection. Deletion of ε shows no phenotype and has no effect on the transcriptional profile of the cell. Determination of the location of ε within the assembly of RNA polymerase core by single-particle analysis suggests that it binds toward the downstream side of the DNA binding cleft. Due to the structural similarity of ε with Gp2 and the fact they bind similar regions of RNA polymerase, we hypothesize that ε may serve a role in protection from phage infection.

Original languageEnglish
Pages (from-to)3622-3632
Number of pages11
JournalJournal of Bacteriology
Volume196
Issue number20
DOIs
Publication statusPublished - 4 Aug 2014
Externally publishedYes

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