Disulfide cross-linking influences symbiotic activities of nodule peptide NCR247
| Autor: | Elizabeth M. Nolan, Graham C. Walker, Jon Penterman, Andrew J. Wommack, Mohammed Shabab, Hartmut T. Bocker, Joel S. Griffitts, Markus F. F. Arnold, Paul A. Price |
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| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Amino Acid Motifs Peptide Host Specificity Rhizobia 03 medical and health sciences Structure-Activity Relationship Bacterial Proteins Gene Expression Regulation Plant Nitrogen Fixation Medicago truncatula Cysteine Disulfides Symbiosis Plant Proteins chemistry.chemical_classification Sinorhizobium meliloti Multidisciplinary biology Oxidative folding food and beverages Membrane Transport Proteins Gene Expression Regulation Bacterial Biological Sciences biology.organism_classification 030104 developmental biology chemistry Biochemistry Cytoplasm Peptides Root Nodules Plant Intracellular Signal Transduction |
| Popis: | Interactions of rhizobia with legumes establish the chronic intracellular infection that underlies symbiosis. Within nodules of inverted repeat-lacking clade (IRLC) legumes, rhizobia differentiate into nitrogen-fixing bacteroids. This terminal differentiation is driven by host nodule-specific cysteine-rich (NCR) peptides that orchestrate the adaptation of free-living bacteria into intracellular residents. Medicago truncatula encodes a family of >700 NCR peptides that have conserved cysteine motifs. NCR247 is a cationic peptide with four cysteines that can form two intramolecular disulfide bonds in the oxidized forms. This peptide affects Sinorhizobium meliloti transcription, translation, and cell division at low concentrations and is antimicrobial at higher concentrations. By preparing the three possible disulfide–cross-linked NCR247 regioisomers, the reduced peptide, and a variant lacking cysteines, we performed a systematic study of the effects of intramolecular disulfide cross-linking and cysteines on the activities of an NCR peptide. The relative activities of the five NCR247 variants differed strikingly among the various bioassays, suggesting that the NCR peptide-based language used by plants to control the development of their bacterial partners during symbiosis is even greater than previously recognized. These patterns indicate that certain NCR bioactivities require cysteines whereas others do not. The results also suggest that NCR247 may exert some of its effects within the cell envelope whereas other activities occur in the cytoplasm. BacA, a membrane protein that is critical for symbiosis, provides protection against all bactericidal forms of NCR247. Oxidative folding protects NCR247 from degradation by the symbiotically relevant metalloprotease HrrP (host range restriction peptidase), suggesting that disulfide bond formation may additionally stabilize NCR peptides during symbiosis. |
| Databáze: | OpenAIRE |
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