9QXQ

native structure of full-length pesticidal protein Cry1Ca18 at pH9, from crystals formed in vivo

Summary for 9QXQ

• Entry DOI: 10.2210/pdb9qxq/pdb
• Descriptor: Crystaline entomocidal protoxin, CALCIUM ION, ZINC ION, ... (4 entities in total)
• Functional Keywords: bacterial toxin, toxin
• Biological source: Bacillus thuringiensis
• Total number of polymer chains: 1
• Total formula weight: 134959.36

Authors

Best, H.L.,Williamson, L.J.,Rizkallah, P.J.,Oberthur, D.,Crickmore, N.,Berry, C. (deposition date: 2025-04-16, release date: 2026-02-11, Last modification date: 2026-03-04)

Primary citation

Best, H.L.,Williamson, L.J.,Cutts, A.B.,Galchenkova, M.,Yefanov, O.,Bryce-Sharron, N.,Heath, E.A.,de Wijn, R.,Schubert, R.,Munke, A.,Henkel, A.,Klopprogge, B.,Scheer, T.E.S.,Kremling, V.,Awel, S.,Pena, G.,Knoska, J.,Keloth, A.,Maracke, J.,Letrun, R.,Sobolev, E.,Bielecki, J.,Melo, D.,Kantamneni, S.,Doerner, K.,Kloos, M.,Schulz, J.,Xavier, P.L.,Lauffer, M.,Villanueva, M.,Caballero, P.,Waller-Evans, H.,Lloyd-Evans, E.,Uetrecht, C.,Bean, R.,Chapman, H.N.,Crickmore, N.,Rizkallah, P.J.,Berry, C.,Oberthur, D.
The long and short of it: Distinct natural crystal packing strategies of Cry toxins from Bacillus thuringiensis.
Structure, 2026

PubMed Abstract: Bacillus thuringiensis (Bt) strains naturally produce pesticidal proteins as nanocrystalline inclusions that are extraordinarily stable in aqueous environments, but which dissolve selectively at specific pH conditions. These proteins have been used in agriculture for >50 years and are critical to global food security. The majority of previously determined Bt Cry protein structures lack the extended C-terminal "crystallization domain," which is thought to stabilize crystal packing and control selective solubility in insect targets, often via manipulation of disulfide bridges. It has also recently been shown to influence toxicity and target specificity. Here, we use serial femtosecond crystallography (SFX) to determine high-resolution full-length native structures of Cry1Ca18 (1.65 Å) and Cry8Ba2 (2.27 Å) in their natural nanocrystalline state. Differences in cysteine content (19 versus 4 residues) reveal distinct in vivo crystal-stabilization strategies. Understanding Bt toxin domain architecture and natural crystal formation is essential for improving biopesticide design and advancing agricultural genetic engineering.

PubMed: 41734756
DOI: 10.1016/j.str.2026.01.014

Experimental method

X-RAY DIFFRACTION (1.65 Å)