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The pH-dependent membrane stability and insertion mechanism of GALA peptide
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1  Faculdade de Ciências da Universidade de Lisboa


The cellular membrane is an essential component of all cells. Distributed on the cellular membrane are many different proteins, either integrated or in interaction, with a variety of functions, namely assisting in membrane transport. GALA is a helical peptide that is prone to protonation, at acidic pH, followed by insertion in the membrane [1]. In its folded form, GALA has an amphiphilic structure, and shows a concentration-dependent tendency to aggregate in multimeric structures inside the membrane, such that the polar glutamate residues face toward each other and the apolar residues face toward the membrane’s lipid tails [1].

In this preliminary study, we used Constant-pH molecular dynamics (CpHMD) simulations [2] to study the conformation and protonation behaviour of GALA as a monomer and as a dimer (parallel or anti-parallel configurations) in the membrane. From these results, we obtained the effects of the initial step of GALA aggregation, particularly, in the secondary structure stabilization and the shifts in the pKa values of the different glutamate residues [2]. In the future, these results will serve as the basis for expanding this study to larger aggregated complexes with 3, 5 or 10 monomer subunits.

Keywords: GALA, CpHMD