Roberto J. Brea
University of Santiago de Compostela
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Publication
Featured researches published by Roberto J. Brea.
Journal of the American Chemical Society | 2009
César Reiriz; Roberto J. Brea; Rocío Arranz; José L. Carrascosa; Alejandra V. Garibotti; Brendan Manning; José M. Valpuesta; Ramon Eritja; Luis Castedo; Juan R. Granja
The formation and full characterization of single self-assembling alpha,gamma-peptide nanotubes (alpha,gamma-SPNs) is described. The introduction of C(60) into cyclic peptides allows the preparation of supramolecular 1D fullerene arrangements induced by peptide nanotube formation under appropriate conditions.
Proceedings of the National Academy of Sciences of the United States of America | 2007
Roberto J. Brea; Luis Castedo; Juan R. Granja; M. Ángeles Herranz; Luis Sánchez; Nazario Martín; Wolfgang Seitz; Dirk M. Guldi
Bio-inspired cyclopeptidic heterodimers built on β-sheet-like hydrogen-bonding networks and bearing photoactive and electroactive chromophores on the outer surface have been prepared. Different cross-strand pairwise relationships between the side chains of the cyclic α,γ-peptides afford the heterodimers as three nonequivalent dimeric species. Steady-state and time-resolved spectroscopies clearly show an electron transfer process from π-extended tetrathiafulvalene, covalently attached to one of the cyclopeptides, to photoexcited [60]fullerene, located on the complementary cyclopeptide. The charge-separated state was stabilized for up to 1 μs before recombining and repopulating the ground state. Our current example shows that cyclopeptidic templates can be successfully used to form light-harvesting/light-converting hybrid ensembles with a distinctive organization of donor and acceptor units able to act as efficient artificial photosystems.
Chemistry: A European Journal | 2011
Laura P. Hernández‐Eguía; Roberto J. Brea; Luis Castedo; Pablo Ballester; Juan R. Granja
The design and synthesis of two α,γ-cyclic octapeptides decorated with one and two Zn-porphyrin units in their periphery is described. In nonpolar organic solvents the α,γ-cyclic octapeptides quantitatively self-assemble into Zn-bis- or -tetraporphyrin architectures that could act as molecular tweezers. The self-assembly process, however, is not regioselective and affords a mixture of different regioisomers that are involved in chemical exchange processes. The regioisomers with the Zn-porphyrin units positioned in register with respect to each other are proposed to be the less abundant species in the solution mixture. It has been demonstrated that the coordination of 1,4-diazabicyclo[2.2.2]octane (DABCO) to the supramolecular bis- or tetraporphyrin tweezers is an effective way to achieve regioisomeric control of the self-assembled mixture of dimers. Thus, DABCO functions as an external molecular trigger and, when used under strict stoichiometric control with respect to the Zn-porphyrin units, provokes the exclusive formation of self-assembled dimers with a cofacial arrangement of Zn-porphyrin units through the formation of sandwich-type complexes. The use of excess DABCO fragments the sandwich complexes and affords open dimers of high stoichiometry with DABCO molecules axially monocoordinated to the Zn-porphyrin units, probably as a regioisomeric mixture. In the case of Zn-tetraporphyrin tweezers, the ditopic coordination of DABCO at the two binding sites shows a moderate positive cooperativity factor, αP=5. These assemblies have potential applications as light-induced energy and electron-transfer switches regulated by DABCO coordination; such applications would require the introduction of additional chromophores in the cyclic peptide scaffold.
Chemistry-an Asian Journal | 2011
Roberto J. Brea; María Jesús Pérez‐Alvite; Michele Panciera; Manuel Mosquera; Luis Castedo; Juan R. Granja
Cyclic octapeptides composed of α-amino acids alternated with cis-3-aminocycloalkanecarboxylic acids, self-assemble as drumlike dimers through β-sheet-like, backbone-to-backbone hydrogen bonding. Heterodimerization appears to be significantly more favored than homodimerization, and this represents a novel approach for the design and fabrication of highly stable heterodimeric assemblies. A multicomponent equilibrium network based on fluorescently derivatized self-assembling α,γ-cyclic octapeptides has been successfully used to form light-harvesting/light-converting ensembles with a distinctive organization of donor and acceptor units able to act as efficient artificial photosystems.
Chemical Communications | 2007
Roberto J. Brea; Luis Castedo; Juan R. Granja
Dimeric nanotube segments with pore diameters of up to 17 A have been obtained by self-assembly from new alpha,gamma-cyclic peptides.
Journal of the American Chemical Society | 2017
Roberto J. Brea; Christian M. Cole; Brent R. Lyda; Libin Ye; R. Scott Prosser; Roger K. Sunahara; Neal K. Devaraj
Cell transmembrane receptors play a key role in the detection of environmental stimuli and control of intracellular communication. G protein-coupled receptors constitute the largest transmembrane protein family involved in cell signaling. However, current methods for their functional reconstitution in biomimetic membranes remain both challenging and limited in scope. Herein, we describe the spontaneous reconstitution of adenosine A2A receptor (A2AR) during the de novo formation of synthetic liposomes via native chemical ligation. The approach takes advantage of a nonenzymatic and chemoselective method to rapidly generate A2AR embedded phospholiposomes from receptor solubilized in n-dodecyl-β-d-maltoside analogs. In situ lipid synthesis for protein reconstitution technology proceeds in the absence of dialysis and/or detergent absorbents, and A2AR assimilation into synthetic liposomes can be visualized by microscopy and probed by radio-ligand binding.
Langmuir | 2017
Takafumi Enomoto; Roberto J. Brea; Ahanjit Bhattacharya; Neal K. Devaraj
A major goal of synthetic biology is the development of rational methodologies to construct self-assembling non-natural membranes, which could enable the efficient fabrication of artificial cellular systems from purely synthetic components. However, spatiotemporal control of artificial membrane formation remains both challenging and limited in scope. Here, we describe a new methodology to promote biomimetic phospholipid membrane formation by the photochemical activation of a catalyst-sensitizer dyad via an intramolecular photoinduced electron-transfer process. Our results offer future opportunities to exert spatiotemporal control over artificial cellular constructs.
ACS central science | 2017
Roberto J. Brea; Neal K. Devaraj
Using the inherent strain in ETP compounds can shoot cargo across cell membranes without the need for endosomal escape.
Chemical Society Reviews | 2010
Roberto J. Brea; César Reiriz; Juan R. Granja
Angewandte Chemie | 2005
Roberto J. Brea; Manuel Amorín; Luis Castedo; Juan R. Granja