[Todos] Seminario Conjunto INIFTA-IFLP. Prof. Igal Szleifer. Universidad de Northwestern

[Gabriel Longo]

Estimadas/os, 

Quedan todas/os invitadas/os al próximo seminario a realizarse el
VIERNES 25 DE OCTUBRE A LAS 11HS. 

El mismo estará a cargo del Prof. Dr. IGAL SZLEIFER. Departamentos de
Ingeniería Biomédica, Química y Medicina. UNIVERSIDAD DE NORTHWESTERN.
EE.UU. 

Su charla se titula: 
"Nanopores: Protein Confinement" 

Se envía a continuación un breve resumen:
1) How Does Confinement Change Ligand-Receptor Binding Equilibrium?
Protein Binding in Nanopores and Nanochannels 

We present systematic studies for the binding of small model proteins to
ligands attached to the inner walls of long nanochannels and short
nanopores by polymeric tethers. Binding of proteins to specific ligands
inside nanometric channels and pores leads to changes in their ionic
conductance, which have been exploited in sensors that quantify the
concentration of the proteins in solution. The theoretical predictions
presented in this work are aimed to provide a fundamental understanding
of protein binding under geometrically confined environments and to
guide the design of this kind of nanochannel-based sensors. The theory
predicts that the fraction of the channel volume filled by bound
proteins is a nonmonotonic function of the channel radius, the length of
the tethers, the surface density of the ligands and the size of the
proteins. 

2) Orientational Pathways during Protein Translocation through
Polymer-Modified Nanopores 

Protein translocation through nanopores holds significant promise for
applications in biotechnology, biomolecular analysis, and medicine.
However, the interpretation of signals generated by the translocation of
the protein remains challenging. In this way, it is crucial to gain a
comprehensive understanding on how macromolecules translocate through a
nanopore and to identify what are the critical parameters that govern
the process. In this study, we investigate the interplay between protein
charge regulation, orientation, and nanopore surface modifications using
a theoretical framework that allows us to explicitly take into account
the acid-base reactions of the titrable amino acids in the proteins and
in the polyelectrolytes grafted to the nanopore surface. Our goal is to
thoroughly characterize the translocation process of different proteins
(GFP, β- lactoglobulin, lysozyme, and RNase) through nanopores modified
with weak polyacids. Our calculations show that the charge regulation
mechanism exerts a profound effect on the translocation process. The
pH-dependent interactions between proteins and charged polymers within
the nanopore lead to diverse free energy landscapes with barriers,
wells, and flat regions dictating translocation efficiency. Comparison
of different proteins allows us to identify the significance of protein
isoelectric point, size, and morphology in the translocation behavior.
Taking advantage of these insights, we propose pH responsive nanopores
that can load proteins at one pH and release them at another, offering
opportunities for controlled protein delivery, separation, and sensing
applications. 

El evento tendrá lugar en el AUDITORIO ¨Prof. Dr. Luis N. Epele¨ del
IFLP, sito en la diagonal 113 entre 63 y 64.

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Gabriel S. Longo, PhD
Investigador Independiente - CONICET
Profesor Adjunto - Dpto. Física, UNLP
Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas
(INIFTA),
UNLP-CONICET
Diag. 113 y Calle 64
(B1906ZAA) La Plata, Argentina
Phone: +54 (221) 425-7430/7291, ext:195
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