25 años de la Declaración de Brasilia

25 años de la Declaración de Brasilia. La Carrera de Relaciones Internacionales - UPC y la Academia Diplomática del Perú "Javier Pérez de Cuellar" organizaron el foro para conmemorar el magno evento, el día 31 de octubre. Altas personalidades y expertos de ambos países disertaron sobre las relaciones entre Ecuador y Perú antes de la firma de la Declaración, así como sus reflexiones sobre el futuro de las relaciones bilaterales. El contexto histórico de las relaciones bilaterales anterior a la firma del Acta estuvo a cargo del ex-canciller Néstor Popolizio, seguido de las disertaciones temáticas : Profesor Rollin Thorne (historia); Embajador Hugo de Zela (relaciones políticas) y Doctor Carlos Posada (relaciones económicas-comerciales). Respecto a las perspectivas futuras de las relaciones de los dos países la presentación estuvo a cargo del ex-canciller José Antonio García Belaunde, seguido de las presentaciones temáticas: Embajador del Ecuador Galo Yepez (relaciones políticas); Embajador José Serrano Herrera (relaciones económicas-comerciales); Doctor, Luis Espinoza, (visión financiera); Embajador Vicente Rojas (aspectos sociales) y doctor Fernando León (asuntos ambientales). La moderación estuvo a cargo de las Embajadoras Beatriz Ramacciotti y Marcela López Bravo. El Embajador Manuel De Cossio, Director General de Estudios y Estrategias de Política Exterior del Ministerio peruano de Relaciones Exteriores realizó las conclusiones finales del importante encuentro.Evento realizado el 31 de octubre de 2023

Mecanismo de transferencia de protones de la enzima oxidasa multicobre de thermus thermophilus hb27 por cristalografía de rayos X\ua0No hay /

\ua0tesis que para obtener el grado de Doctorado en Ciencias Bioquímicas, presenta Hugo Javier Serrano Posada ; asesor Enrique Rudiño Piñera114 páginas :\ua0ilustracionesDoctorado en Ciencias Bioquímicas\ua0UNAM, Instituto de Biotecnologia,\ua0201

Molecular Dynamics of a Thermostable Multicopper Oxidase from <em>Thermus thermophilus</em> HB27: Structural Differences between the Apo and Holo Forms

<div><p>Molecular dynamic (MD) simulations have been performed on <em>Tth</em>-MCO, a hyperthermophilic multicopper oxidase from <em>thermus thermophilus</em> HB27, in the apo as well as the holo form, with the aim of exploring the structural dynamic properties common to the two conformational states. According to structural comparison between this enzyme and other MCOs, the substrate in process to electron transfer in an outer-sphere event seems to transiently occupy a shallow and overall hydrophobic cavity near the Cu type 1 (T1Cu). The linker connecting the β-strands 21 and 24 of the second domain (loop (β21–β24)_D2) has the same conformation in both states, forming a flexible lid at the entrance of the electron-transfer cavity. Loop (β21–β24)_D2 has been tentatively assigned a role occluding the access to the electron-transfer site. The dynamic of the loop (β21–β24)_D2 has been investigated by MD simulation, and results show that the structures of both species have the same secondary and tertiary structure during almost all the MD simulations. In the simulation, loop (β21–β24)_D2 of the holo form undergoes a higher mobility than in the apo form. In fact, loop (β21–β24)_D2 of the holo form experiences a conformational change which enables exposure to the electron-transfer site (open conformation), while in the apo form the opposite effect takes place (closed conformation). To confirm the hypothesis that the open conformation might facilitate the transient electron-donor molecule occupation of the site, the simulation was extended another 40 ns with the electron-donor molecule docked into the protein cavity. Upon electron-donor molecule stabilization, loops near the cavity reduce their mobility. These findings show that coordination between the copper and the protein might play an important role in the general mobility of the enzyme, and that the open conformation seems to be required for the electron transfer process to T1Cu.</p> </div

Root mean square deviation (RMSD) from the crystallographic structures of the C^α atoms as a function of simulation time for apo-<i>Tth</i>-MCO form (black line), holo-<i>Tth</i>-MCO (red line) and holo-<i>Tth</i>-MCO without loop (β21–β24)_D2 (blue line).

<p>Root mean square deviation (RMSD) from the crystallographic structures of the C^α atoms as a function of simulation time for apo-<i>Tth</i>-MCO form (black line), holo-<i>Tth</i>-MCO (red line) and holo-<i>Tth</i>-MCO without loop (β21–β24)_D2 (blue line).</p

Average conformations of ABTS inside the electron-transfer complex formed with holo-<i>Tth</i>-MCO electron-transfer cavity during the last 25 ns of MD simulation. Residues in close proximity (<0.4 nm) to the ABTS (orange stick models) are represented as green stick models and coppers are shown in Van der Waals representation.

<p>B) The non-bonded short-range Coulomb (black line) and Lennard–Jones (red line) interaction between holo-<i>Tth</i>-MCO and ABTS as a function of time.</p

RMSF analysis of the C^α atoms of TNC’s residues (A) and the second sphere carboxylate residues (B), for apo-<i>Tth-</i>MCO (black) and holo-<i>Tth</i>-MCO (red) for the last 18 ns of a 38 ns-long simulation.

<p>RMSF analysis of the C^α atoms of TNC’s residues (A) and the second sphere carboxylate residues (B), for apo-<i>Tth-</i>MCO (black) and holo-<i>Tth</i>-MCO (red) for the last 18 ns of a 38 ns-long simulation.</p

Structural evidences of the average conformations accessible in the 38 ns MD simulation for the holo-<i>Tth</i>-MCO (snapshots A–C) and apo-<i>Tth</i>-MCO forms (snapshots D–E).

<p>The different secondary structure elements are represented in light blue cartoons. The protein regions involved in the open-closure of the electron-transfer site are in deep blue cartoons: Loop (β21–β24)_D2 and α4-helix_D2 for snapshots A-B and D, loop (β21–β24)_D2 and (187-α4-201)_D2 for snapshot C, loop (β21–β24)_D2, loop (β25–β26)_D3 and loop (β28–β29)_D3 for snapshot E.</p

Structural topology of holo-<i>Tth</i>-MCO and superposition with others MCÓs.

<p>A) Multinuclear metal site of the holo-<i>Tth</i>-MCO. B) Structural depiction of the three cupredoxin domains of holo-<i>Tth</i>-MCO, (domain 1, green), (domain 2, light blue) and (domain 3, yellow), the loop (β21–β24)_D2 is in deep blue cartoons. C) Ribbon superposition of the holo forms of <i>Tth</i>-MCO (green), CueO (red, PDB entry 1N68) and CotA (blue, PDB entry 1UVW), the main differences among them are represented in cartoon structure. Mononuclear copper center (T1Cu) is shown in blue and trinuclear copper cluster (TNC) is shown in orange (T3Cu) and red (T2Cu) Van der Waals representation.</p