Identification of methionine synthase (Sal k 3), as a novel allergen of Salsola kali pollen.
Salsola kali pollen is a common cause of pollinosis during summer and early fall in desert and semi-desert regions. The aim of this study was the identification and characterization of Sal k 3, a new allergen from S. kali pollen. S. kali pollen extract was fractionated by SDS-PAGE and the allergenic profile was determined by IgE-immunoblotting using twelve S. kali allergic patients. Protein identification was carried out by the means of mass spectrometry. Using degenerated primers, two DNA fragments encoding N- and C-terminal domain of Sal k 3 were amplified by PCR, then cloned into the PTZ57R/T vector and sequenced. The open reading frame of Sal k 3 fragments were subcloned in the pET-32b(+) vector, expressed in E. coli, and purified by Ni2+ affinity chromatography. The IgE-binding capacity of rSal k 3 fragments was then studied by IgE-immunoblotting, inhibition assays, and skin prick tests. A 45-kDa allergen was identified as a fragment of the cobalamin-independent methionine synthase (MetE) by mass spectrometry and was detected in the sera of 8/12 (66.6%) of S. kali allergic patients. Moreover, inhibition assays demonstrated that the purified rSal k 3 fragments were similar to their counterparts in the crude extract. Sal k 3 represents a new allergen of S. kali pollen and seems to be an important allergenic compound in S. kali pollen.
Assarehzadegan
Mohammad Ali
MA
Department of Immunology, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. assarehzadeganma831@mums.ac.ir
Sankian
Mojtaba
M
Jabbari
Farahzad
F
Tehrani
Mohsen
M
Falak
Reza
R
Varasteh
Abdolreza
A
D000485:Allergens / Q000737:chemistry / Q000276:immunology*; D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate; D007073:Immunoglobulin E / Q000276:immunology; D008297:Male; D008780:Methyltransferases / Q000737:chemistry / Q000276:immunology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010455:Peptides / Q000032:analysis / Q000737:chemistry; D010936:Plant Extracts / Q000276:immunology; D010940:Plant Proteins / Q000032:analysis / Q000737:chemistry; D011058:Pollen / Q000201:enzymology* / Q000276:immunology*; D011994:Recombinant Proteins / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification; D031248:Salsola / Q000201:enzymology* / Q000276:immunology*; D020539:Sequence Analysis, Protein; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D040681:Structural Homology, Protein
D000485:Allergens; D010455:Peptides; D010936:Plant Extracts; D010940:Plant Proteins; D011994:Recombinant Proteins; D007073:Immunoglobulin E; D008780:Methyltransferases; C022725:5-methyltetrahydropteroyltriglutamate-homocysteine S-methyltransferase