Dr Joern Werner BBSRC Multidomain Protein Complexes

Higher organisms are made from assemblies of many different kinds of cells that are surrounded by a network of large molecules forming an extracellular matrix. This tissue plays an active role in a wide range of biological processes. Some pathogens exploit and manipulate normal matrix functions to their own ends by molecular interactions with specific components of the host matrix. In many cases the molecular recognition is mediated by multivalent interactions of multidomain proteins whose components are intrinsically dynamic. Protein dynamics is emerging as an important determinant for protein ligand recognition. Nuclear magnetic resonance (NMR) is uniquely suited to study protein dynamics with atomic resolution on a wide range of timescales. We implement and develop novel NMR based techniques to characterise order and dynamics in multidomain protein peptide complexes. We employ multiple residual dipolar couplings in a range of alignment media together with heteronuclear relaxation experiments to study backbone and sidechain dynamics. The interpretation of the NMR data is complemented by molecular dynamics. Simulations. The continuation of a successful collaboration with Dr Jennifer Potts¿s group in Oxford provides us with a biologically important multivalent protein peptide complex involved in host pathogen interactions. We propose to study order and flexibility of a panel of N-terminal fibronectin (Fn) domain pairs 1F1-2F1, 2F1-3F1, 4F1-5F1 as well as the entire N-terminal Fn domain 1-5F1 in complex with high affinity binding peptides from the fibronectin binding protein SfbI from S. pyogenes that bind to either an individual F1 module or an F1-F1 module pair. We expect that comparative dynamics studies of structurally highly related subsystems of this complex will yield insight in the modulation of affinity and selectivity by dynamics.