Swapping the N- and C-terminal domains of human apolipoprotein E3 and AI reveals insights into their structure/activity relationship.

Apolipoprotein (apo) E3 and apoAI are exchangeable apolipoproteins that play a dominant role in regulating plasma lipoprotein metabolism. ApoE3 (299 residues) is composed of an N-terminal (NT) domain bearing a 4-helix bundle and a C-terminal (CT) domain bearing a series of amphipathic α-helices. ApoAI (243 residues) also comprises a highly helical NT domain and a less structured CT tail.

pH influenced molecular switching with micelle bound cavitands.

A series of resorcinarene host-amphiphilic guest complexes have been developed where guest orientation in the host is drastically influenced by pH. Guests appended with a trimethylammonium and a tert-butyl group switch orientation by 180° in response to a buildup of negative charge in the cavitand host.