6U6G

Solution NMR structure of the nodule-specific cysteine-rich peptide NCR044 from Medicago truncatula

Summary for 6U6G

• Entry DOI: 10.2210/pdb6u6g/pdb
• NMR Information: BMRB: 30660
• Descriptor: Putative Late nodulin (1 entity in total)
• Functional Keywords: fungal disease, antifungal agent, antifungal protein, defensin-like
• Biological source: Medicago truncatula (Barrel medic)
• Total number of polymer chains: 1
• Total formula weight: 4329.22

Authors

Velivelli, S.L.S.,Buchko, G.W.,Shah, D.M. (deposition date: 2019-08-29, release date: 2019-10-09, Last modification date: 2024-10-23)

Primary citation

Velivelli, S.L.S.,Czymmek, K.J.,Li, H.,Shaw, J.B.,Buchko, G.W.,Shah, D.M.
Antifungal symbiotic peptide NCR044 exhibits unique structure and multifaceted mechanisms of action that confer plant protection.
Proc.Natl.Acad.Sci.USA, 117:16043-16054, 2020

PubMed Abstract: In the indeterminate nodules of a model legume , ∼700 nodule-specific cysteine-rich (NCR) peptides with conserved cysteine signature are expressed. NCR peptides are highly diverse in sequence, and some of these cationic peptides exhibit antimicrobial activity in vitro and in vivo. However, there is a lack of knowledge regarding their structural architecture, antifungal activity, and modes of action against plant fungal pathogens. Here, the three-dimensional NMR structure of the 36-amino acid NCR044 peptide was solved. This unique structure was largely disordered and highly dynamic with one four-residue α-helix and one three-residue antiparallel β-sheet stabilized by two disulfide bonds. NCR044 peptide also exhibited potent fungicidal activity against multiple plant fungal pathogens, including and three spp. It inhibited germination in quiescent spores of In germlings, it breached the fungal plasma membrane and induced reactive oxygen species. It bound to multiple bioactive phosphoinositides in vitro. Time-lapse confocal and superresolution microscopy revealed strong fungal cell wall binding, penetration of the cell membrane at discrete foci, followed by gradual loss of turgor, subsequent accumulation in the cytoplasm, and elevated levels in nucleoli of germlings. Spray-applied NCR044 significantly reduced gray mold disease symptoms caused by the fungal pathogen in tomato and tobacco plants, and postharvest products. Our work illustrates the antifungal activity of a structurally unique NCR peptide against plant fungal pathogens and paves the way for future development of this class of peptides as a spray-on fungistat/fungicide.

PubMed: 32571919
DOI: 10.1073/pnas.2003526117

Experimental method

SOLUTION NMR