No abstract

Cry11Aa and Cry11Ba are the two most potent toxins produced by mosquitocidal Bacillus thuringiensis subsp. israelensis and jegathesan, respectively. The toxins naturally crystallize within the host; however, the crystals are too small for structure determination at synchrotron sources. Therefore, we applied serial femtosecond crystallography at X-ray free electron lasers to in vivo-grown nanocrystals of these toxins. The structure of Cry11Aa was determined de novo using the single-wavelength anomalous dispersion method, which in turn enabled the determination of the Cry11Ba structure by molecular replacement. The two structures reveal a new pattern for in vivo crystallization of Cry toxins, whereby each of their three domains packs with a symmetrically identical domain, and a cleavable crystal packing motif is located within the protoxin rather than at the termini. The diversity of in vivo crystallization patterns suggests explanations for their varied levels of toxicity and rational approaches to improve these toxins for mosquito control.

No abstract

The first clues on the origins of the peculiar abilities of crystallophore (Tb‐Xo4) are reported. Tb‐Xo4 is a terbium complex that allows both the nucleation of protein crystals and the solving of their structures. Herein, a detailed study of the binding of Tb‐Xo4 in a set of six structures is presented. It evidences the adaptability of the complex towards different crystallization conditions and protein environments, thanks to a variety of supramolecular interactions. The cover shows Tb‐Xo4/FprA protein co‐crystals and the related crystal packing that has been determined. The magnifying glass depicts a detailed view of a Tb‐Xo4 dimer binding site. More information can be found in the Communication by O. Maury, F. Riobé, E. Girard, E. Dumont, et al. on page 9739.