Isolation of Calcium Binding Protein Interaction Peptides Using T7 Phage Display

Calcium Binding Proteins (CaBP) play relevant roles in processes such as mitosis, cytokenesis, microtubule-based cytoskeleton formation among organisms such as yeast, algae, mice and humans. Elucidation of the identity of these protein families is important to determine their function in the cell. The use of combinatorial chemistry strategies, such as Phage Display, allows the identification of interaction partners among proteins in a rapid and effective manner. In this research, four CaBP were used as target ligands to determine and isolate interaction partners from T7 Phage Display cDNA library from Human Colon. The CaBP targets were first adhered to the ELISA plate and after performing the blocking reaction, three rounds of biopanning were developed and the presence of interaction phages was determined using phage lift. The putative phages displaying interacting peptides were isolated, and tested for the presence of an insert by PCR, to further determine the identity of the fragment by in silico analysis. The data confirms the presence of interaction peptides in all four targets. Identification of proteins, such as attractin and vimentin, were detected through this analysis. From a total of 1.1 x 10⁷ of T7 phages in the library, the number and diversity of the phages cloned inserts was reduced approximately to 4.0 x 10³ PFU/mL. The specificity assay is in progress to confirm recognition among partners interaction. These findings have shown several of CaBP interaction peptides that can be used to expand the knowledge in biomedical research and cellular biosensors.