Global chain properties of an all L-alpha-eicosapeptide with a secondary alpha -helix and its all retro D-inverso-alpha-eicosapeptide estimated through the modeling of their CZE determined electrophoretic mobilities

JULIO A. DEIBER; MARÍA V. PIAGGIO; MARTA B. PEIROTTI

ELECTROPHORESIS

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2014 vol. 35 p. 755 - 761

0173-0835

Several global chain properties of relatively long peptides composed of 20 amino acid residues are estimated through the modeling of their experimental effective electrophoretic mobilities determined by CZE for 2<pH<6. In this regard, an all L-alpha-eicosapeptide including a secondary alpha-helix (Peptide 1) and its all retro D-inverso- alpha-eicosapeptide (Peptide 2) are considered. Despite Peptides 1 and 2 are isomeric chains they do not present similar global conformations in the whole range of pH studied. These peptides may also differ in the quality of BGE components-chain interactions depending on the pH value. Three Peptide 1 fragments (Peptides 3, 4 and 5) are also analyzed in this framework with the following purposes: (i) visualization of the effects of initial and final strands at each side of the alpha-helix on the chain global conformations of Peptide 1 at different pHs, and (ii) analysis of global chain conformations of Peptides 1 and 2, and Peptide 1 fragments in relation to their pI values. Also the peptide maximum and minimum hydrations predicted by the model, compatible with experimental effective electrophoretic mobilities at different pHs, are quantified and discussed, and needs for further research concerning chain hydration are proposed. It is shown that CZE is a useful analytical tool for peptidomimetic designs and purposes.