Isolation, characterization and structure-elicitor activity relationships of hibernalin and its two oxidized forms from Phytophthora hibernalis Carne 1925.
Three alpha-elicitins, named hibernalin1, hibernalin2 and hibernalin3 (hib1, hib2 and hib3, respectively), were isolated by reverse phase-low-pressure liquid chromatography from culture filtrates of Phytophthora hibernalis Carne 1925, the causal agent of citrus lemon brown rot. Hib1 proved to be identical to syringicin previously isolated from culture filtrates of Phytophthora syringae. Hib2 and hib3 shared the same primary structure with hib1, but contained, at position 50, Met sulphoxide or sulphone, respectively. By SDS-PAGE, the three proteins showed the same electrophoretic mobility, corresponding to about 10 kDa. Exact M(r) values were obtained by MALDI-TOF-MS (10,194.82 for hib1, 10,209.33 for hib2 and 10,223.80 for hib3), while by ESI-MS an M(r) value of 10,194.90 was found for hib1 and no results for hib2 and hib3. The hibernalin forms showed a high propensity to self-association, after exposure to acetonitrile. Hib1 showed to be active in both the hypersensitivity response and electrolytes leakage assays; the sample containing hib1 and hib2 was only weakly active in the first assay and inactive in the second assay, while the sample containing all three hibernalin forms proved to be inactive in both tests. It is proposed that the different activities of the three hibernalin samples could be very likely attributed to both Met50 oxidation and aggregation.
Capasso
Renato
R
Dipartimento di Scienze del Suolo, della Pianta, dell' Ambiente e delle Produzioni Animali, Facoltà di Agraria, Università degli Studi di Napoli "Federico II", I-80055 Portici (NA), Italy. renato.capasso@unina.it
Di Maro
Antimo
A
Cristinzio
Gennaro
G
De Martino
Antonio
A
Chambery
Angela
A
Daniele
Addolorata
A
Sannino
Filomena
F
Testa
Antonino
A
Parente
Augusto
A
D020418:Algal Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D000595:Amino Acid Sequence; D002853:Chromatography, Liquid; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010838:Phytophthora / Q000737:chemistry*; D011506:Proteins; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013329:Structure-Activity Relationship; D014026:Nicotiana / Q000187:drug effects
D020418:Algal Proteins; D011506:Proteins; C085101:elicitin, Phytophthora