Abstract: The present disclosure relates to a composition that includes a perovskite of A2BX4, where A includes an R-form of a chiral molecule of at least one of and/or an S-form of the chiral molecule, B includes a cation, X includes an anion, R1 includes a first carbon chain having between 2 and 5 carbon atoms, R2 includes at least one of a hydrogen atom, a halogen atom, a carboxylic acid group, an alkoxy group, and/or a second carbon chain, and R3 includes a third carbon chain.

Abstract: The disclosure provides amino acid sequence variants of Botulinum neurotoxin (BoNT) proteases that cleave (VAMP1, VAMP2, VAMP7, VAMP8, SNAP25, SNAP23, PTEN, etc.) and methods of evolving the same. In some embodiments, proteases described by the disclosure are useful for cleaving proteins found in a cell, that is in an intracellular environment. In some embodiments, proteases described by the disclosure are useful for treating diseases associated with increased or aberrant VAMP7, VAMP8, SNAP23 or PTEN expression or activity, for example, cancer and neurological disorders. Some aspects of this disclosure provide methods for generating BoNT protease variants by continuous directed evolution.