Figure 1.
Figure 1. Structures of PI-TkoII, PI-PfuI, and PI-SceI. A:
Stereo ribbon diagram of PI-TkoII. PI-TkkoII contains the
endonuclease, Hint, III, and IV domains colored in green, blue,
light blue, and pink, respectively. Active site residues are
shown. B: Ribbon diagram of PI-PfuI. C: Ribbon diagram of
PI-SceI. D: Domain organization and multiple sequence alignment
of PI-TkoII, PI-PfuI, and PI-SceI. The aligned sequences were
displayed in ESPript.[24] Secondary structures were calculated
by DSSP.[25] Secondary structure annotations and numberings on
top correspond to PI-TkoII. -Helices
are represented by spirals and -strand
by arrows. White lettering boxed with a red background indicates
residues that are conserved in all three sequences, and red
lettering indicates similar residues. The conserved sequence
blocks of inteins are indicated.
The above figure is reprinted
by permission from John Wiley & Sons, Inc.:
Proteins
(2006,
63,
711-715)
copyright 2006.
-Helices
are represented by spirals and 
-strand
by arrows. White lettering boxed with a red background indicates
residues that are conserved in all three sequences, and red
lettering indicates similar residues. The conserved sequence
blocks of inteins are indicated.