Chapter Three Dynamical Behavior of Somatostatin-14 and Its Cyclic Analogues as Analyzed in Bulk and on Plasmonic Silver Nanoparticles

Publication date: 2018 Source:Advances in Protein Chemistry and Structural Biology, Volume 112 Author(s): Belén Hernández, Yves-Marie Coïc, Eduardo López-Tobar, Santiago Sanchez-Cortes, Bruno Baron, Fernando Pflüger, Sergei G. Kruglik, Régis Cohen, Mahmoud Ghomi Primarily known as the inhibitor of growth hormone release, the role of somatostatin in many other inhibiting activities upon binding to its five G-protein-coupled receptors has been elucidated. Because of the short half-life of somatostatin, a number of synthetic analogues were elaborated for this peptide hormone. Herein, after recalling the main somatostatin therapeutic interests, we present the dynamical behavior of somatostatin-14 and its two currently used synthetic cyclic analogues, octreotide and pasireotide. Physical techniques, such as fluorescence, UV–visible absorption, circular dichroism, Raman spectroscopy, surface-enhanced Raman spectroscopy, and transmission electron microscopy, were jointly used in order to get information on the solution structural features, as well as on the anchoring sites of the three peptides on silver colloids. While somatostatin-14 adopts a rather unordered chain within the submillimolar concentration range, its cyclic analogues were revealed to be ordered, i.e., stabilized either in a type-II′ β-turn (octreotide) or in a face-to-face γ-turn/type-I β-turn (pasireotide) structure. Nevertheless, a progressive structuring trend was observed in som...
Source: Advances in Protein Chemistry and Structural Biology - Category: Biochemistry Source Type: research