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Figure 3.
Figure 3. (a) Close-up stereo view of the superposition of
the N-terminal subdomain of preDnaE (cyan) and exDnaE (purple).
(b) Stereo view of the modeled N-terminal catalytic module of
Ssp DnaE intein. (e) Close-up stereo view of the superposition
of the C-terminal subdomain of preDnaE (cyan) and exDnaE
(purple). (f) Stereo view of the modeled C-terminal catalytic
module of Ssp DnaE intein. Residues are shown in ball-and-stick
representations. The broken lines indicate hydrogen bonds, and
bond distances are labeled. (c), (d), (g), (h) and (i) A
chemical mechanism proposed for splicing the Ssp DnaE intein.
The red arrows indicate the routes of nucleophilic attacks in
the splicing pathway. Broken lines indicate hydrogen bonds. The
tetrahedral intermediate formed by an N-S acyl rearrangement at
Cys1 is not shown.
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