With the holiday season finally behind us, the usual routine is returning to work at the CCDC. The CCDC window cleaner, Steve, visited today. Gazing idly though my now clean window at Steve, up his ladder, my mind wandered to ladderanes, a rather unusual group of supramolecular structures containing two or more edge-sharing rings of cyclobutane.
These molecules were first synthesised for use in the field of molecular design; as these rigid, highly-strained molecules (along with other types of ‘rigid molecular racks’) allowed the exact positioning of various functional groups for the study of electron- and energy-transfer processes.
These ladder-like molecules soon gained further attention, however, when it was reported in a publication in 2002 (doi:10.1038/nature01128) that nature had got there first. Ladderane-type structures were found in anaerobic ammonium-oxidizing (anammox) marine bacteria. It is suggested ladderane-type lipids help increase the density of a particular anammoxosome membrane to form a barrier against diffusion of toxic molecules, produced as the bacteria derive their energy.