Chromophore formation in GFP: computational modeling of the immature form of wild-type GFP

The main reason green fluorescent protein (GFP) is so useful in molecular imaging is the fact that its chromophore is formed autocatalytically. We have been using molecular mechanics to examine chromophore formation since 1995 that is well before the first crystal structures of GFP were solved. Our calculations have resulted in a number of predictions that have been borne out by subsequent experiments and a number of them that haven't. Recently we have been supplementing these calculations with calculations based on the crystal structures of immature GFP mutants (i.e. the precyclized form). Preliminary results from these calculations have shown that immature GFP does form a tight-turn in the chromophore forming region, and that chromophore cyclization is probably catalyzed in the manner proposed by Getzoff et al (Biochemistry 44: 1960-1970, 2005).