Poster #RP117
Sequence Motifs, and Profiles, of Insulin Binding
Steven Bottomley*, Jessica Mitchell*, Brian Plewright*, Erik Helmerhorst*
*WABRI, Curtin University, Perth, Australia
The aim of our project was to develop sequence motifs, and profiles, of insulin-binding regions in the human insulin receptor. We experimentally generated hundreds of overlapping 9mer and 15mer peptides, representing the alpha subunit of the insulin receptor sequence, and determined their ability to bind 125Insulin. Multiple alignment (using Clustal W), and a pattern graph technique (Pratt 2.0), of insulin-binding peptides was then used to derive twelve putative sequence motifs in Prosite format. Profiles were also derived by arranging all of the insulin-binding peptides, of the insulin receptor, into ten insulin-binding regions and aligning them with equivalent regions in the insulin receptors of other species.
The twelve putative insulin-binding sequence motifs were used to scan the Swiss-Prot database. Most lacked sensitivity and selectivity but two motifs were found to be reasonably selective. Profiles of at least two insulin-binding regions were also sensitive for insulin receptor proteins and selective against IGF-1 proteins or insulin receptor related proteins. We are further investigating the possibility of using either insulin-binding sequence motifs, or insulin-binding profiles, as predictive tools to identify insulin-binding regions in other proteins.