By Peter Mirau
Functional nanostructures in nature are often constructed from proteins and inorganic materials templated to obtain composites with superior mechanical or optical properties. We are creating composites by non-enzymatically cross linking energy-rich polyphosphate (polyP) with low complexity PolyAcidic, Serine and Lysine (PASK) domains in selected proteins. 31P NMR is used to identify cross linking sites as phosphoramidate linkages to lysine and the stoichiometry of the products is determined using the polyP diffusion coefficients measured with pulse-field gradient NMR (DOSY). The PASK domain lysines are identified using pseudo-3D NMR experiments by combining HMQC optimized for phosphoramidate linkages with NOESY and TOCSY experiments. We also use 31P NMR to monitor the reactivity of the constructs in the presence of enzymes that create and modify polyP. By understanding the reaction mechanism we aim to optimize the properties of composites.
Session #9: Proteins, Peptides, Genes/Vaccines – With our Magnets Now You’re Seen