Multi-Approach Analysis for the Identification of Proteases within Birch Pollen

• Main Authors: Olivia E. McKenna, Gernot Posselt, Peter Briza, Peter Lackner, Armin O. Schmitt, Gabriele Gadermaier, Silja Wessler, Fatima Ferreira
• Format: Article
• Language: English
• Published: MDPI AG 2017-07-01
• Series: International Journal of Molecular Sciences
• Subjects: birch pollen; allergy; protease; proteome; transcriptome; zymogram
• Online Access: https://www.mdpi.com/1422-0067/18/7/1433

Birch pollen allergy is highly prevalent, with up to 100 million reported cases worldwide. Proteases in such allergen sources have been suggested to contribute to primary sensitisation and exacerbation of allergic disorders. Until now the protease content of Betula verrucosa, a birch species endemic to the northern hemisphere has not been studied in detail. Hence, we aim to identify and characterise pollen and bacteria-derived proteases found within birch pollen. The pollen transcriptome was constructed via de novo transcriptome sequencing and analysis of the proteome was achieved via mass spectrometry; a cross-comparison of the two databases was then performed. A total of 42 individual proteases were identified at the proteomic level. Further clustering of proteases into their distinct catalytic classes revealed serine, cysteine, aspartic, threonine, and metallo-proteases. Further to this, protease activity of the pollen was quantified using a fluorescently-labelled casein substrate protease assay, as 0.61 ng/mg of pollen. A large number of bacterial strains were isolated from freshly collected birch pollen and zymographic gels with gelatinase and casein, enabled visualisation of proteolytic activity of the pollen and the collected bacterial strains. We report the successful discovery of pollen and bacteria-derived proteases of Betula verrucosa.