Abstract
We report that bacterial RNA polymerase (RNAP) is the functional cellular target of the depsipeptide antibiotic salinamide A (Sal), and we report that Sal inhibits RNAP through a novel binding site and mechanism. We show that Sal inhibits RNA synthesis in cells and that mutations that confer Sal-resistance map to RNAP genes. We show that Sal interacts with the RNAP active-center "bridge-helix" cap, comprising the "bridge-helix" N-terminal hinge, "F-loop", and "link region". We show that Sal inhibits nucleotide addition in transcription initiation and elongation. We present a crystal structure that defines interactions between Sal and RNAP and effects of Sal on RNAP conformation. We propose that Sal functions by binding to the RNAP bridge-helix cap and preventing conformational changes of the bridge-helix N-terminal hinge necessary for nucleotide addition. The results provide a target for antibacterial drug discovery and a reagent to probe conformation and function of the bridge-helix N-terminal hinge.
| Original language | English (US) |
|---|---|
| Article number | e02451 |
| Journal | eLife |
| Volume | 2014 |
| Issue number | 3 |
| DOIs | |
| State | Published - Apr 30 2014 |
| Externally published | Yes |
Keywords
- Allosteric inhibitor
- Antibacterial agent
- Antibacterial resistance
- Antibiotic
- Bridge helix
- Bridge helix N-terminal hinge
- Bridge-helix cap
- CBR703
- Crystal structure
- F-loop
- Inhibitor
- Link region
- Lipiarmycin
- Myxopyronin
- Nucleotide addition
- RNA polymerase
- Resistance mutant
- Resistance spectrum
- Rifampin
- Rifamycin
- Salinamide A
- Salinamide B
- Salinamides
- Streptolydigin
- Transcription
- Transcription elongation
- Transcription initiation
- Trigger loop
ASJC Scopus subject areas
- Neuroscience(all)
- Immunology and Microbiology(all)
- Biochemistry, Genetics and Molecular Biology(all)