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Solution structure of the phytotoxic protein PcF: The first characterized member of the Phytophthora PcF toxin family
Author(s) -
Nicastro Giuseppe,
Orsomando Giuseppe,
Ferrari Elena,
Manconi Lucia,
Desario Filomena,
Amici Adolfo,
Naso Alessia,
Carpaneto Armando,
Pertinhez Thelma A.,
Ruggieri Silverio,
Spisni Alberto
Publication year - 2009
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.168
Subject(s) - toxin , effector , biology , mimicry , phytophthora , molecular mimicry , protein family , structural motif , protein–protein interaction , biochemistry , botany , genetics , gene , ecology , antibody
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.