Isolation and Identification of the Proteins Contributing to English Ivy Nanoparticle Formation

English ivy (Hedera helix L.) has previously been shown to secrete a high strength nanocomposite adhesive from the root hairs of its adventitious roots. This ivy nanocomposite adhesive is composed of uniform proteinaceous nanoparticles, 50–80 nm, within a polysaccharide matrix. In addition to their role in adhesion, recent studies have demonstrated that isolated ivy nanoparticles have ultraviolet (UV) protective abilities. Considering the importance of these organic nanoparticles in a variety of applications, the goal of this work was to identify the proteins involved in the formation of the ivy nanoparticles using an “omics” approach. Since the whole genome has not been sequenced for English ivy, the first step in this work was to generate a transcriptome for the ground and adventitious roots. The next step was to separate individual proteins from a previously identified high molecular weight (HMW) band observed in SDS-PAGE gels. By adjusting the reducing conditions, it was possible to separate this HMW band into nine distinct bands ranging in molecular weight from 10-175 kDa. Each band was then sequenced using LC/MS/MS, and blasted against the UniProt database and the ivy transcriptome. The results of this “omics” analysis identified 13 protein candidates involved in the formation of the nanoparticles. The identification of these components, along with their known biological function, is essential to further work into in vitro formation of ivy nanoparticles for numerous applications.