Peptide Bond trans-cis Isomerization and Acylimine Formation in Chromophore Maturation of the Red Fluorescent Proteins

Abstract

In red fluorescent proteins such as DsRed, an acylimine is formed from the Phe65-Gln66 linkage in GFP-like immature form, while it shows a cis configuration in its mature state. To date, the relationship between acylimine formation and trans-cis isomerization is still unresolved. We have calculated bond rotation profiles for mature and immature chromophores within the protein using our own n-layered integrated molecular orbital and molecular mechanism (ONIOM) approach. The results suggested that the isomerization is barrierless in acylimine formed in the mature state, suggesting that the acylimine formation precedes the trans-cis isomerization in DsRed chromophores. Further decomposition ana..