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Quorum sensing is a cell–cell communication process that bacteria use to orchestrate group behaviors. Quorum sensing is mediated by signal molecules called autoinducers. Autoinducers are often structurally similar, raising questions concerning how bacteria distinguish among them. Here, we use thePseudomonas aeruginosaLasR quorum-sensing receptor to explore signal discrimination. The cognate autoinducer, 3OC12homoserine lactone (3OC12HSL), is a more potent activator of LasR than other homoserine lactones. However, other homoserine lactones can elicit LasR-dependent quorum-sensing responses, showing that LasR displays ligand promiscuity. We identify mutants that alter which homoserine lactones LasR detects. Substitution at residue S129 decreases the LasR response to 3OC12HSL, while enhancing discrimination against noncognate autoinducers. Conversely, the LasR L130F mutation increases the potency of 3OC12HSL and other homoserine lactones. We solve crystal structures of LasR ligand-binding domains complexed with noncognate autoinducers. Comparison with existing structures reveals that ligand selectivity/sensitivity is mediated by a flexible loop near the ligand-binding site. We show that LasR variants with modified ligand preferences exhibit altered quorum-sensing responses to autoinducers in vivo. We suggest that possessing some ligand promiscuity endows LasR with the ability to optimally regulate quorum-sensing traits.
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Metal- versus ligand-centered reactivity of a cobalt-phenylenediamide complex with electrophiles
A cobalt complex with a phenylenediamide redox-active ligand reacts with an electrophilic trifluoromethyl source to generate a robust Co–CF3bond, while in contrast, treatment with alkyl electrophiles occurs at the ligand scaffold.
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- Award ID(s):
- 2117792
- PAR ID:
- 10581505
- Publisher / Repository:
- Royal Society of Chemistry
- Date Published:
- Journal Name:
- Dalton Transactions
- Volume:
- 53
- Issue:
- 31
- ISSN:
- 1477-9226
- Page Range / eLocation ID:
- 13174 to 13183
- Subject(s) / Keyword(s):
- Cobalt complexes Ligand-centered reactivity
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/d4dt01655f
