Pollen allergen Pla a 1 and similar plant proteins
The major Platanus acerifolia pollen allergen Pla a 1 belongs to a class of allergens related to proteinaceous invertase and pectin methylesterase inhibitors. Platanus acerifolia is an important cause of pollinosis; Pla a 1 has a prevalence of about 80% among plane tree pollen-allergic patients. Recombinant Pla a 1 binds IgE in vitro, similar to its natural counterpart, rendering it suitable for specific diagnosis and structural studies. Invertase inhibitors are structurally similar to those of pectin methylesterase (PMEIs), an enzyme that is involved in the control of pectin metabolism and is structurally unrelated to invertases. All inhibitors share a size of about 18 kDa, two strictly conserved disulfide bridges and only moderate sequence homology (about 20% sequence identity).