Structure overlay of OYE1 (white; PDB: 1OYA), cpOYE154 (gray; PDB: 4RNX), and cpOYE303 (blue;
PDB: 4RNU).
Super positioning of the three structures was based on the FMN cofactor,
shown in sticks. The three helices at the dimer interface (α4,
α5, and α6) and the native OYE1 termini are labeled. The
two inserts focus on the new termini regions in cpOYE154 (right) and
cpOYE303 (left). Red arrows mark the locations of backbone cleavage
(shown on OYE1) upon circular permutation, illustrating the portions
of protein sequence invisible in the CP variants due to a lack of
electron density.