Interaction of l‑Phenylalanine with a Phospholipid Monolayer at the Water–Air Interface

The
interaction of l-phenylalanine with a 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayer at the air–water
interface was explored using a combination of experimental techniques
and molecular dynamics (MD) simulations. By means of Langmuir trough
methods and Brewster angle microscopy, l-phenylalanine was
shown to significantly alter the interfacial tension and the surface
domain morphology of the DPPC film. In addition, confocal microscopy
was used to explore the aggregation state of l-phenylalanine
in the bulk aqueous phase. Finally, MD simulations were performed
to gain molecular-level information on the interactions of l-phenylalanine and DPPC at the interface. Taken together, these results
show that l-phenylalanine intercalates into a DPPC film at
the air–water interface, thereby affecting the surface tension,
phase morphology, and ordering of the DPPC film. The results are discussed
in the context of biological systems and the mechanism of diseases
such as phenylketonuria.