title: Application of linker technique to trap transiently interacting protein complexes for structural studies.
abstract: Protein-protein interactions are key events controlling several biological processes. We have developed and employed a method to trap transiently interacting protein complexes for structural studies using glycine-rich linkers to fuse interacting partners, one of which is unstructured. Initial steps involve isothermal titration calorimetry to identify the minimum binding region of the unstructured protein in its interaction with its stable binding partner. This is followed by computational analysis to identify the approximate site of the interaction and to design an appropriate linker length. Subsequently, fused constructs are generated and characterized using size exclusion chromatography and dynamic light scattering experiments. The structure of the chimeric protein is then solved by crystallization, and validated bothin vitroandin vivoby substituting key interacting residues of the full length, unlinked proteins with alanine. This protocol offers the opportunity to study crucial and currently unattainable transient protein interactions involved in various biological processes.
authors.affiliation: Department of Biological Sciences, National University of Singapore, Singapore, 117543.
authors.forename: Vishnu Priyanka
authors.initials: VP
authors.lastname: Reddy Chichili
authors.affiliation: Department of Biological Sciences, National University of Singapore, Singapore, 117543.
authors.forename: Veerendra
authors.initials: V
authors.lastname: Kumar
authors.affiliation: Department of Biological Sciences, National University of Singapore, Singapore, 117543.
authors.forename: J
authors.initials: J
authors.lastname: Sivaraman
keywords: glycine-rich linker; protein-protein interactions; transient interactions