CHROMOPHORE-ASSISTED LASER INACTIVATION OF CELLULAR PROTEINS

This chapter discusses chromophore-assisted laser inactivation (CALI) as a means of addressing functional interactions in biology with a high degree of spatial and temporal resolution. CALI is analogous to cellular laser ablation but the damage is localized to a protein of interest by covalently attaching the chromophore, malachite green, to an antibody that specifically binds to that protein. The laser energy is targeted to effectively inactivate the bound protein while unbound proteins are unaffected. This perturbation of function occurs at the time of laser irradiation and only within the diameter of the laser spot. This opens up the possibility of perturbing the function of a given protein in a spatially and temporally controlled manner. The chapter describes the mechanism of CALI and shows that the CALI is spatially restricted to within 34Ǻ, of the dye molecules and that the mechanism of CALI is mediated by photogenerated hydroxyl radicals. The high reactivity and very short lifetime of this radical species is responsible for the spatial specificity of CALI. © 1994, Elsevier Science Publishers, B.V. All rights reserved.