Fig. 3: Structural relationships of the NTD of Cry78Aa with other trefoil domains illustrated by a phylogenetic tree plot. | Communications Biology

Fig. 3: Structural relationships of the NTD of Cry78Aa with other trefoil domains illustrated by a phylogenetic tree plot.

From: The crystal structure of Cry78Aa from Bacillus thuringiensis provides insights into its insecticidal activity

Fig. 3

Four of the structures used for comparison were identified from a structural similarity search through the Protein Data Bank (PDB) conducted by the Dali server (using Cry78Aa residues 13–155 as the probe, see also Supplementary Table 2). The top four hits included HA33 from C. botulinum (PDB: 5B2H), the HA1 subcomponent of botulinum type C toxin (PDB: 3AH1), ricin B lectin from C. thermocellum (PDB: 3VSF) and mosquitocidal toxin from L. aphaericus (PDB: 2VSE). The remaining structures chosen for comparison, including Cry35Ab1 from B. thuringiensis (PDB: 4JP0), BinA, and BinB (PDB: 5FOY), were selected based on their overall structural similarity with Cry78Aa. That is, they all consisted of a trefoil domain covalently linked to a β-pore-forming domain. The phylogenetic tree was generated by using MEGA-X (10.0.2) and the input sequences of the relevant structures were downloaded from the PDB. The selected trefoil domains, including Cry78Aa, can be divided into 3 clades, which are indicated by black, blue, and purple lines. The NTD of Cry78Aa has the closest homology with ricin B lectin and was assigned to the same clade (both marked in blue). Superposition of all the trefoil domains exhibited an overall similar conformation.

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