Interaction of Phenylalanine with DPPC membranes: more than an hydrophobic interaction

ROSA, A.S.; CUTRO, ANDREA C.; DISALVO, E ANIBAL; FRIAS, M. DE LOS ANGELES

Santiago del Estero

Congreso; Maria Frias; 2015

Sociedad Argentina de Biofísica

L- Phenylalanine (Phe) plays an important role in different physiological processes such as antimicrobial activity of certain peptides as clavanin, whire its presence provides sufficient peptide hydrophobicity, affinity and conformational flexibility, necessary for its action1. In aqueous solution, Phe has a very high hidrophobicity that could influence the hydrogen bond network and its environment. Thus packing and hydration appears to affect Phe insertion. In the first case, it´s expected that lateral pressure would promote deffects due to mismatch of lipid head groups and a concomitant partial dehydration. In the second case, water extrusion by the pypertonic media increases the packing promoting defects by changes in curvature or dehydration, at least in certain regions of the bilayer. The hydrophobic defects may include water arrangements to favor hydrophovic interaction. Thus the different states of hydration may affect the Phe insertion.Previous works have demonstrated that defects are related with the relative populations of hydrated and non-hydrated carbonyl groups of the phospholipids. They seem to involve water exposure of hydrophobic regions so the nature of the interactions of Phe is a point of interest, particularly, if structural packing defects where Phe is intended to insert are water accessible in the gel state. In this context, the interaction of L- Phe with DPPC molecules at different degrees of hydration was studied by means of FTIR/ATR spectroscopy.