TY - JOUR
T1 - Role of cysteine residues and disulfide bonds in the activity of a legume root nodule-specific, cysteine-rich peptide
AU - Haag, Andreas F.
AU - Kerscher, Bernhard
AU - Dall'Angelo, Sergio
AU - Sani, Monica
AU - Longhi, Renato
AU - Baloban, Mikhail
AU - Wilson, Heather M.
AU - Mergaert, Peter
AU - Zanda, Matteo
AU - Ferguson, Gail P.
PY - 2012/3/30
Y1 - 2012/3/30
N2 - The root nodules of certain legumes including Medicago truncatula produce >300 different nodule-specific cysteine-rich (NCR) peptides. Medicago NCR antimicrobial peptides (AMPs) mediate the differentiation of the bacterium, Sinorhizobium meliloti into a nitrogen-fixing bacteroid within the legume root nodules. In vitro, NCR AMPs such as NCR247 induced bacteroid features and exhibited antimicrobial activity against S. meliloti. The bacterial BacA protein is critical to prevent S. meliloti from being hypersensitive toward NCR AMPs. NCR AMPs are cationic and have conserved cysteine residues, which form disulfide (S-S) bridges. However, the natural configuration of NCRAMPS-S bridges and the role of these in the activity of the peptide are unknown. In this study, we found that either cysteine replacements or S-S bond modifications influenced the activity of NCR247 against S. meliloti. Specifically, either substitution of cysteines for serines, changing the S-S bridges from cysteines 1-2, 3-4 to 1-3, 2-4 or oxidation of NCR247 lowered its activity against S. meliloti. We also determined that BacA specifically protected S. meliloti against oxidized NCR247. Due to the large number of different NCRs synthesized by legume root nodules and the importance of bacterial BacA proteins for prolonged host infections, these findings have important implications for analyzing the function of these novel peptides and the protective role of BacA in the bacterial response toward these peptides.
AB - The root nodules of certain legumes including Medicago truncatula produce >300 different nodule-specific cysteine-rich (NCR) peptides. Medicago NCR antimicrobial peptides (AMPs) mediate the differentiation of the bacterium, Sinorhizobium meliloti into a nitrogen-fixing bacteroid within the legume root nodules. In vitro, NCR AMPs such as NCR247 induced bacteroid features and exhibited antimicrobial activity against S. meliloti. The bacterial BacA protein is critical to prevent S. meliloti from being hypersensitive toward NCR AMPs. NCR AMPs are cationic and have conserved cysteine residues, which form disulfide (S-S) bridges. However, the natural configuration of NCRAMPS-S bridges and the role of these in the activity of the peptide are unknown. In this study, we found that either cysteine replacements or S-S bond modifications influenced the activity of NCR247 against S. meliloti. Specifically, either substitution of cysteines for serines, changing the S-S bridges from cysteines 1-2, 3-4 to 1-3, 2-4 or oxidation of NCR247 lowered its activity against S. meliloti. We also determined that BacA specifically protected S. meliloti against oxidized NCR247. Due to the large number of different NCRs synthesized by legume root nodules and the importance of bacterial BacA proteins for prolonged host infections, these findings have important implications for analyzing the function of these novel peptides and the protective role of BacA in the bacterial response toward these peptides.
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U2 - 10.1074/jbc.M111.311316
DO - 10.1074/jbc.M111.311316
M3 - Article
C2 - 22351783
AN - SCOPUS:84859487293
SN - 0021-9258
VL - 287
SP - 10791
EP - 10798
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 14
ER -