Recent insights into mechanisms of cellular toxicity and cell recognition associated with the ABC family of pore-forming toxins.

ABC toxins are pore-forming toxins characterised by the presence of three distinct components assembled into a hetero-oligomeric toxin complex ranging in size from 1.5-2.5 MDa.

Stereospecific Formation of the Isomer of Bis-crown-Containing Cyclobutane upon [2 + 2] Photocycloaddition of an (18-Crown-6)stilbene Induced by Self-Assembly via Hydrogen Bonding.

The formation and the spectroscopic and structural properties of 1:1 and 2:1 (ligand-to-dication) complexes of an (18-crown-6)stilbene with ethane-1,2-diammonium diperchlorate in MeCN were studied by UV-vis and NMR spectroscopy and by density functional theory calculations. Prolonged UV irradiation of 2:1 mixtures of the crown stilbene and the diammonium salt led to the formation of two main photoproducts, namely, the single -"head-to-head" photodimer of the crown stilbene ( cyclobutane) due to supramolecular-assisted [2 + 2] photocycloaddition and a crown ether derivative of phenanthrene due to a photoinduced electrocyclization reaction. The cyclobutane was isolated by preparative photolysis, followed by chromatography.

Pseudodimeric Complexes of an (18-Crown-6)stilbene with Styryl Dyes Containing an Ammonioalkyl Group: Synthesis, Structure, and Stereospecific [2 + 2] Cross-Photocycloaddition.

A new efficient method was proposed for the synthesis of (18-crown-6)stilbene; the structure of the product was confirmed by X-ray diffraction analysis. In MeCN, this compound forms pseudodimeric complexes with -(2-ammonioethyl)-4-styrylpyridinium and -(3-ammoniopropyl)-4-styrylpyridinium diperchlorates via hydrogen bonding between the ammonium group and the crown ether oxygen atoms. The ammonioethyl derivative was synthesized for the first time.