Solution structure of the phytotoxic protein PcF: the first characterized member of the Phytophthora PcF toxin family.
The PcF protein from Phytophthora cactorum is the first member of the "PcF toxin family" from the plant pathogens Phytophthora spp. It is able to induce withering in tomato and strawberry leaves. The lack of sequence similarity with other proteins hampers the identification of the molecular mechanisms responsible for its toxicity. Here, we show that the six cysteines form a disulphide pattern that is exclusive for PcF and essential for the protein withering activity. The NMR solution structure identifies a novel fold among protein effectors: a helix-loop-helix motif. The presence of a negatively charged surface suggests that it might act as a site of electrostatic interaction. Interestingly, a good fold match with Ole e 6, a plant protein with allergenic activity, highlighted the spatial superimposition of a stretch of identical residues. This finding suggests a possible biological activity based on molecular mimicry.
Nicastro
Giuseppe
G
National Institute for Medical Research (NIMR-MRC), The Ridgeway, London NW7 1AA, United Kingdom.
Orsomando
Giuseppe
G
Ferrari
Elena
E
Manconi
Lucia
L
Desario
Filomena
F
Amici
Adolfo
A
Naso
Alessia
A
Carpaneto
Armando
A
Pertinhez
Thelma A
TA
Ruggieri
Silverio
S
Spisni
Alberto
A
D000595:Amino Acid Sequence; D018257:Helix-Loop-Helix Motifs / Q000502:physiology; D008969:Molecular Sequence Data; D010838:Phytophthora / Q000737:chemistry / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D016415:Sequence Alignment; D014118:Toxins, Biological / Q000737:chemistry* / Q000378:metabolism
C107504:OLE6 protein, Olea europaea; C088192:Pcf protein, Phytophthora cactorum; D010940:Plant Proteins; D014118:Toxins, Biological