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Proc Natl Acad Sci U S A. 2019 Jan 22;116(4):1273-1278. doi: 10.1073/pnas.1817352116. Epub 2019 Jan 9.

Structural mechanism of transcription inhibition by lasso peptides microcin J25 and capistruin.

Author information

1
Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065.
2
Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544.
3
Department of Chemistry, Princeton University, Princeton, NJ 08544.
4
Department of Molecular Biology, Princeton University, Princeton, NJ 08544.
5
Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065; darst@rockefeller.edu.

Abstract

We report crystal structures of the antibacterial lasso peptides microcin J25 (MccJ25) and capistruin (Cap) bound to their natural enzymatic target, the bacterial RNA polymerase (RNAP). Both peptides bind within the RNAP secondary channel, through which NTP substrates enter the RNAP active site, and sterically block trigger-loop folding, which is essential for efficient catalysis by the RNAP. MccJ25 binds deep within the secondary channel in a manner expected to interfere with NTP substrate binding, explaining the partial competitive mechanism of inhibition with respect to NTPs found previously [Mukhopadhyay J, Sineva E, Knight J, Levy RM, Ebright RH (2004) Mol Cell 14:739-751]. The Cap binding determinant on RNAP overlaps, but is not identical to, that of MccJ25. Cap binds further from the RNAP active site and does not sterically interfere with NTP binding, and we show that Cap inhibition is partially noncompetitive with respect to NTPs. This work lays the groundwork for structure determination of other lasso peptides that target the bacterial RNAP and provides a structural foundation to guide lasso peptide antimicrobial engineering approaches.

KEYWORDS:

RNA polymerase; X-ray crystallography; capistruin; lasso peptide; microcin J25

PMID:
30626643
PMCID:
PMC6347699
DOI:
10.1073/pnas.1817352116
[Indexed for MEDLINE]
Free PMC Article

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