Understanding and modeling proteinochromism, also known as spectral tuning or color tuning in proteins, receives more and more attention because of the increasing interest in biomolecular imaging, optogenetics and related photochemical tools. The methods of computational chemistry are indispensable tools to support research on proteinochromism but also require the combination of many different techniques, making it a formidable task even for experienced researchers. The field has seen some major improvements recently, especially by an advanced modeling of the protein environment as a polarizable embedding. Here, all relevant aspects of computational proteinochromism modeling, from the basic theory to specific computational considerations, are reviewed and exemplified based on a detailed discussion of theoretical studies on electronic excitations in the green fluorescent protein.
Keywords: Fluorescent proteins, theoretical spectroscopy, protein spectroscopy, QM/MM, protein modeling, computational chemistry.