The plot thickens: Gelation by phenylalanine in water and dimethyl sulfoxide

Phenylalanine (Phe) is an amino acid of great interest as coupling of an aromatic group with a chiral hydrophilic region imparts a number of unique properties. Recently there has been an increased interest in the crystalline and gel forms of this compound, part as a result of the complex and undetermined structures of the resulting materials and the relationship of the solid forms of Phe with the disease phenylketonuria. In this report, we highlight the relationship between gelation, crystallization, and the dynamics of self-assembly processes of Phe. We do this by describing the gelation of the amino acid, the gel to crystal relationship, crystal structure predictions for this relatively simple compound, and the dynamics of assembly as determined by NMR in both water and dimethyl sulfoxide. This will provide guidance to future research into Phe assemblies, possible treatments for phenylketonuria, and diseases related to formation of amyloid-like fibers.