Pro-apoptotic bax-α1 synthesis and evidence for β-sheet to α-helix conformational change as triggered by negatively charged lipid membranes

Abstract

Solid phase synthesis of Bax-α 1, the 25 amino acids domain (14TSSEQIMKTGALLLQGFIQDRAGRM38) of the proapoptotic Bax protein has been accomplished using Fmoc chemistry. A new fast and harmless protocol is described for complete TFA removal from the purified peptide powder leading to a final purity greater than 98% as controlled by 19F-NMR, UV and MALDI-TOF mass spectrometry. Secondary structure was determined in various solution and membrane media using UV Circular Dichroism. In water solution, Bax-α 1 is present as a mixture of β-sheet and unstructured (random coil) conformations. A marked change from β-sheet to α-helix secondary structures is observed upon interaction with negatively charge..