title: Major linear IgE epitopes of mountain cedar pollen allergen Jun a 1 map to the pectate lyase catalytic site.
abstract: Resolution of the 3D structures and IgE epitopes of allergens may identify common or conserved features of allergens. Jun a 1, the predominant allergen in mountain cedar pollen, was chosen as a model for identifying common structural and functional features among a group of plant allergens. In this study, synthetic, overlapping peptides of Jun a 1 and sera from patients allergic to mountain cedar pollen were used to identify linear epitopes. A 3D model of Jun a 1 was produced using the Bacillus subtiles pectate lyase (PL) as a template and validated with biophysical measurements. This allowed mappings of four IgE binding sites on Jun a 1. Two of the epitopes mapped to turns or loops on the surface of the model structure. The other two epitopes mapped to the beta-sheet region, homologous to the catalytic site of PL. This region of Jun a 1 is highly conserved in the group 1 allergens from other cedar trees as well as microbial PLs. The finding that two out of three major IgE epitopes map to highly conserved catalytic regions of group 1 cedar allergens may help to explain the high degree of cross-reactivity between cedar pollen allergens and might represent a pattern of reactivity common to other allergens with catalytic activity.
authors.affiliation: Department of Pediatrics, Child Health Research Center, University of Texas Medical Branch, 301 University Blvd. Galveston, Galveston, TX 77555-0366, USA. tmidoro@utmb.edu
authors.forename: Terumi
authors.initials: T
authors.lastname: Midoro-Horiuti
authors.forename: Venkatarajan
authors.initials: V
authors.lastname: Mathura
authors.forename: Catherine H
authors.initials: CH
authors.lastname: Schein
authors.forename: Werner
authors.initials: W
authors.lastname: Braun
authors.forename: Shaoning
authors.initials: S
authors.lastname: Yu
authors.forename: Masanao
authors.initials: M
authors.lastname: Watanabe
authors.forename: J Ching
authors.initials: JC
authors.lastname: Lee
authors.forename: Edward G
authors.initials: EG
authors.lastname: Brooks
authors.forename: Randall M
authors.initials: RM
authors.lastname: Goldblum
mesh_terms: D000485:Allergens / Q000276:immunology*; D000595:Amino Acid Sequence; D052179:Antigens, Plant; D020134:Catalytic Domain; D000939:Epitopes / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology*; D018653:Juniperus / Q000276:immunology; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000276:immunology*; D011133:Polysaccharide-Lyases / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
chemical_list: D000485:Allergens; D052179:Antigens, Plant; D000939:Epitopes; D010940:Plant Proteins; C121951:jun a 1 protein, Juniperus ashei; D007073:Immunoglobulin E; D011133:Polysaccharide-Lyases; C023911:pectate lyase