SOLVATOCHROMIC BEHAVIOR OF THE ANIONIC BIOCHROMOPHORE BILIVERDIN INVESTIGATED USING A CRYOGENIC ION TRAP

Abstract

Fluorescent proteins can incorporate a wide variety of chromophores which all lead to different absorption and emission characteristics. In the condensed phase, interactions of chromophores with their chemical environment (e.g., solvents, surrounding protein) change their photophysical properties. By examining these chromophores as mass-selected ions in vacuo, we are able to study their intrinsic photophysical properties without influence from such environments. Here we report electronic and infrared spectra of cryogenically prepared biliverdin anions. We interpret our experimental spectra through analysis of time-dependent density functional theory calculations.