The C-terminal part of microcin B is crucial for DNA gyrase inhibition and antibiotic uptake by sensitive cells

Irina Shkundina, Marina Serebryakova, Konstantin Severinov

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Microcin B (McB) is a ribosomally synthesized antibacterial peptide. It contains up to nine oxazole and thiazole heterocycles that are introduced posttranslationally and are required for activity. McB inhibits the DNA gyrase, a validated drug target. Previous structure-activity analyses indicated that two fused heterocycles located in the central part of McB are important for antibacterial action and gyrase inhibition. Here, we used site-specific mutagenesis of the McB precursor gene to assess the functional significance of the C-terminal part of McB that is located past the second fused heterocycle and contains two single heterocycles as well as an unmodified four-amino-acid C-terminal tail. We found that removal of unmodified C-terminal amino acids of McB, while having no effect on fused heterocycles, has a very strong negative effect on activity in vivo and in vitro. In fact, even nonconservative point substitutions in the last McB amino acid have a very strong effect by simultaneously decreasing uptake and ability to inhibit the gyrase. The results highlight the importance of unmodified McB amino acids for function and open the way for creation of recombinant McB derivatives with an altered or expanded spectrum of antibacterial action.

Original languageEnglish (US)
Pages (from-to)1759-1767
Number of pages9
JournalJournal of bacteriology
Volume196
Issue number9
DOIs
StatePublished - Jan 1 2014

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DNA Gyrase
Anti-Bacterial Agents
Amino Acids
Oxazoles
microcin
Thiazoles
Site-Directed Mutagenesis

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Microbiology

Cite this

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abstract = "Microcin B (McB) is a ribosomally synthesized antibacterial peptide. It contains up to nine oxazole and thiazole heterocycles that are introduced posttranslationally and are required for activity. McB inhibits the DNA gyrase, a validated drug target. Previous structure-activity analyses indicated that two fused heterocycles located in the central part of McB are important for antibacterial action and gyrase inhibition. Here, we used site-specific mutagenesis of the McB precursor gene to assess the functional significance of the C-terminal part of McB that is located past the second fused heterocycle and contains two single heterocycles as well as an unmodified four-amino-acid C-terminal tail. We found that removal of unmodified C-terminal amino acids of McB, while having no effect on fused heterocycles, has a very strong negative effect on activity in vivo and in vitro. In fact, even nonconservative point substitutions in the last McB amino acid have a very strong effect by simultaneously decreasing uptake and ability to inhibit the gyrase. The results highlight the importance of unmodified McB amino acids for function and open the way for creation of recombinant McB derivatives with an altered or expanded spectrum of antibacterial action.",
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The C-terminal part of microcin B is crucial for DNA gyrase inhibition and antibiotic uptake by sensitive cells. / Shkundina, Irina; Serebryakova, Marina; Severinov, Konstantin.

In: Journal of bacteriology, Vol. 196, No. 9, 01.01.2014, p. 1759-1767.

Research output: Contribution to journalArticle

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