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Publication Abstract from PubMed

The crystal protein Cry5B, a pore-forming protein produced by the soil bacterium Bacillus thuringiensis, has been demonstrated to have excellent anthelmintic activity. While a previous structure of the three-domain core region of Cry5B(112-698) had been reported, this structure lacked a key N-terminal extension critical to function. Here we report the structure of Cry5B(27-698) containing this N-terminal extension. This new structure adopts a distinct quaternary structure compared to the previous Cry5B(112-698) structure, and also exhibits a change in the conformation of residues 112-140 involved in linking the N-terminal extension to the three-domain core by forming a random coil and an extended alpha-helix. A role for the N-terminal extension is suggested based on a computational model of the tetramer with the conformation of residues 112-140 in its alternate alpha-helix conformation. Finally, based on the Cry5B(27-698) structure, site-directed mutagenesis studies were performed on Tyr495, which revealed that having an aromatic group or bulky group at this residue 495 is important for Cry5B toxicity.

Insights from the Structure of an Active Form of Bacillus thuringiensis Cry5B.,Li J, Wang L, Kotaka M, Lee MM, Chan MK Toxins (Basel). 2022 Nov 23;14(12):823. doi: 10.3390/toxins14120823. PMID:36548720^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.