POLYMERS AS SURFACE-BASED TETHERS WITH PHOTOLYTIC TRIGGERS ENABLING LASER-INDUCED RELEASE DESORPTION OF COVALENTLY BOUND MOLECULES

A novel design for suface-based macromolecular docking and release is presented together with a strategy to improve and extend biopolymer st ructure determination capabilities. Polymeric surfaces with arrays of tethers for covalent molecular attachment were designed with photolyti c triggers to enable spatially defined, laser-induced uncoupling/desor ption of the tethered molecules. Upon photolytic cleavage, a defined p ortion of the tether (''tail'') remains attached to the biomolecule as a probe. Chemically defined memory, determined by the number of repor ter tails, reflects the biomolecule interaction with tether-probe devi ces encountered (i.e., footprint) on the probe surface. To demonstrate function, a surface of poly(4-vinylpyridine) was extended through the pyridinium nitrogens with spacer arms (-N-ethylsuccinamyl-) producing photolytic pyridinium nitrogen bonds. The photolabile tether was term inated with leaving groups (N-hydroxysulfosuccinimide) for covalent at tachment of biopolymers. An 18-residue peptide (N terminus of human be ta-casein) was covalently docked to these tether-probes, irradiated wi th coherent UV light, and released with two reporter tails of a mass p redicted by tether formation at the two primary amine groups and subse quent photolytic cleavage at the intended site. This is the first demo nstration of polymeric surface structure enabling the covalent docking and laser-induced uncoupling/desorption of intact macromolecules thro ugh the use of photolytic tethers. Surface-based tether-probe devices, operated by coherent light, should advance our ability to explore cov alent modifications in biopolymer structure and alterations in conform ation, generated either in advance of tethering or through chemical/en zymatic manipulations performed directly in. situ.