Multiphoton excitation-evoked chromophore-assisted laser inactivation using green fluorescent protein.

Noninvasive, straightforward methods to inactivate selected proteins in living cells with high spatiotemporal resolution are needed. Chromophore-assisted laser inactivation (CALI) can be used to photochemically inactivate proteins, but it has several drawbacks, such as procedural complexity and nonspecific photodamage. Here we show that by application of multiphoton excitation to CALI, enhanced green fluorescent protein (EGFP) is an effective chromophore for inactivation of a protein's function without nonspecific photodamage in living mammalian cells.