T Aliferis

Publications (4)11.55 Total impact

• Article: Control of Peptide Secondary Structure and Dynamics in Poly(γ-benzyl-l-glutamate)-b-polyalanine Peptides

  A. Gitsas, G. Floudas, M. Mondeshki, H. W. Spiess, T. Aliferis, H. Iatrou, N. Hadjichristidis
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  ABSTRACT: The stability, persistence and dynamics of the peptide secondary motifs are investigated in a series of poly(γ-benzyl-l-glutamate)-b-polyalanine (PBLG-b-PAla) polypeptides through a combination of structural (X-rays, NMR) and dynamic (Dielectric Spectroscopy, NMR) probes. The unfavorable enthalpic interactions between the unlike blocks give rise to nanophase separation that results in the destabilization of PAla β-sheets. Contrary to this, the overall helicity of PBLG α-helices is enhanced. The dynamics of the “defected” amorphous segments and of the more ordered segments are studied by DS and 13C NMR, respectively. These probes provide information on the time scale and the mechanism of molecular and supramolecular motion.
  10/2008;
• Article: "Glass transition" in peptides: temperature and pressure effects.

  P Papadopoulos, G Floudas, I Schnell, H-A Klok, T Aliferis, H Iatrou, N Hadjichristidis
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  ABSTRACT: We report on the origin of the liquid-to-glass transition in a series of oligopeptides of gamma-benzyl-L-glutamate up to the polymer (PBLG), and in Poly-Z-L-lysine (PZLL) and Polyglycine (PGly) using dielectric spectroscopy as a function of temperature and pressure. We show that temperature is the dominant control variable of the dynamics associated with the peptidic "glass transition." This is an intrinsic feature of the peptide dynamics, irrespective of the type of amino acid and of the peptide secondary structure. The influence of the type of secondary structure (alpha helix vs beta sheet) on the liquid-to-glass dynamics is discussed.
  The Journal of Chemical Physics 07/2005; 122(22):224906. · 3.33 Impact Factor
• Article: Nanodomain-induced chain folding in poly(gamma-benzyl-L-glutamate)-b-polyglycine diblock copolymers.

  P Papadopoulos, G Floudas, I Schnell, T Aliferis, H Iatrou, N Hadjichristidis
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  ABSTRACT: We report on the self-assembly mechanism and dynamics in a series of poly(gamma-benzyl-l-glutamate)-b-poly(glycine) (PBLG-b-PGly) diblock copolymers within the composition range 0.67 < or = f(PBLG) < or = 0.97 and the temperature (T) range 303 < T < 433 K. Small- and wide-angle X-ray scattering, (13)C NMR, and differential scanning calorimetry are used for the structure investigation coupled with dielectric spectroscopy for both the peptide secondary structure and the associated dynamics. These techniques provide not only the nanophase morphology but also the type and persistence of peptide secondary structures. The thermodynamic confinement of the blocks within the nanodomains and the disparity in their packing efficiency results in multiple chain folding of the PGly secondary structure that effectively stabilize a lamellar morphology for high f(PBLG). Nanoscale confinement proves to be important in controlling the persistence length of secondary peptide motifs.
  Biomacromolecules 6(4):2352-61. · 5.48 Impact Factor
• Article: Hierarchical self-assembly in diblock copolypeptides of poly(γ-benzyl-l-glutamate) with poly poly(l-leucine) and poly(O-benzyl-l-tyrosine)

  M. Mondeshki, H.W. Spiess, T. Aliferis, H. Iatrou, N. Hadjichristidis, G. Floudas
  European Polymer Journal 47(4):668-674. · 2.74 Impact Factor