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Figure 1.
Figure 1. (a) Diagram of conserved intein motifs of
bifunctional inteins, mini inteins and the Ssp DnaE split
intein. Blocks A and B (black) in the N-terminal subdomain
(magenta) and blocks F and G (black) in the C-terminal subdomain
(yellow) are shared by the splicing domains and the endonuclease
domain is shown in grey. Residues involved in nucleophilic
attack (letters in a box), as well as other highly conserved
amino acids are indicated below the block diagram. (b) A
representation of the Ssp DnaE intein fusions. The exDnaE fusion
protein consists of maltose-binding protein (MBP), the
full-length wild-type Ssp DnaE intein (residues 1-159, which
include 123 amino acid residues from the N terminus and 36 amino
acid residues from the C terminus) with five native extein
residues at its N terminus and three native residues at its C
terminus, and the CBD. The resulting protein exDnaE is splicing
functional. Black arrows indicate the splicing sites of Ssp DnaE
intein. preDnaE consists of CBD, Ssp DnaB intein and the
full-length Ssp DnaE intein with C1A and N159A mutations
(residue 1-159) along with five native extein residues at its N
terminus and three native residues at its C terminus. The black
arrow shows the cleavage site of the modified Ssp DnaB intein.41
The intein proteins after purification are indicated in red.
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