Minischool on Biophysics of Protein Interactions

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Start time: March 9, 2015

Ends on:  March 13, 2015

Location: São Paulo, Brazil

Venue: IFT-UNESP

Organizers / Lecturers:

Fernando Luís Barroso da Silva (USP-Ribeirão Preto, Brazil): On the peculiar electrostatic effects observed in protein systems – a computational approach

Roland Netz (Freie Universität Berlin, Germany): Hydration and dielectric effects at surfaces

Rudolf Podgornik (U. Ljubljana, Slovenia): Charge regulation and electrostatic interactions in proteins

Invited Lecturers:

Ralf Eichhorn (Nordita, Sweden): Theory of phoretic effects induced by the (counter-)ions in the system

Leandro Barbosa (USP-São Paulo, Brazil): Protein interactions as revealed by small-angle x-ray scattering

Yan Levin (UFRGS, Brazil): Introduction to statistical mechanics of charged systems

João Ruggiero Neto (UNESP-Rio Preto, Brazil): Electrostatic and non-electrostatic features in the interaction of lytic peptides with model membranes

Jose Nelson Onuchic (Rice Univ.): Onuchic Minicourse on Energy Landscapes in Biophysics

Description:

The proposed school will compare and creatively confront different modern approaches to highly charged, structured, and disordered Coulomb systems. Its primary purpose will be to merge the different theoretical, experimental and simulation approaches in order to progress towards a unified description of the electrostatic interactions in soft- and bio-matter.  An overview of approximate analytical theories as well as sophisticated simulations will put the students in contact with the state-of-the art research in biophysics and will allow them to build connections between these different theoretical approaches, as well as with the available experimental data.

Besides a poster session, attendants will be also invited to give short talks about their research activity. This school is aimed at graduate students and researchers in the fields of statistical mechanics, materials science, biophysics and nanobiotechnology. There is no registration fee and limited funds are available for travel and local expenses.

This school will be preceded on Sunday March 8 by a one-day minicourse of Prof. Jose Nelson Onochic (Rice University) on Energy Landscapes in Biophysics. 

 Announcement

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Registration: 

ALL participants should register. The registration will be on Sunday, March 8 at the institute from 13:00 to 14:00. You can find arrival instruction at http://www.ictp-saifr.org/?page_id=195

Program:

Evaluations of School 

Abstracts:

Fernando Luís Barroso da Silva (USP-Ribeirão Preto, Brazil): On the peculiar electrostatic effects observed in protein systems – a computational approach
The combination of the (bio)colloidal characteristics (specially size and charge) with pH and the thermal energy result in a unique collection of mesoscopic forces of high importance to the molecular organization and function both in industrial, scientific and biological systems. General physical and modeling issues will be presented. Protein-protein, protein-polyelectrolyte and protein-nanoparticle systems will be used as examples.

Roland R. Netz (Free University Berlin, Germany): Hydration and dielectric effects at surfaces
The molecular layer of water molecules on surfaces is important for the interaction between neutral as well as charged surfaces. We study how hydration and dielectric properties of interfacial water layers can be used to explain diverse phenomena such as the hydration repulsion between phospholipid membranes, cavitation between hydrophobic surfaces, surface capacitance data and the attraction between polar surfaces.

Rudolf Podgornik (U. Ljubljana, Slovenia): Charge regulation and electrostatic interactions in proteins
I will present a detailed account of charge regulation and its consequences for electrostatic interactions between proteins. I will describe a few simplified model systems where explicit calculations are possible and then concentrate on charge regulation in viral protein shells showing their fundamental importance for stability of capsids as well as interactions between proteinaceous capsids in ionic solutions.

Ralf Eichhorn (Nordita, Sweden): Theory of phoretic effects induced by the (counter-)ions in the system
When a charged particle is suspended in liquid solution, its charge is “compensated” by accumulating a non-uniform distribution of charges from the solution (ions) at the particle surface. In presence of an external field, this charge distribution is deformed, leading to a net interaction between the external field and the particle surface. As a result of this interaction, the particle is set into motion and moves through the liquid. We study the theory for such kind of phoretic transport phenomena. As specific examples we discuss electrophoresis (particle motion due to an external electric field) and thermophoresis (particle motion in a temperature gradient).

Leandro Barbosa (USP-São Paulo, Brazil): Protein interactions as revealed by small-angle x-ray scattering
In this presentation, bovine serum albumin, BSA, has been investigated at three different concentrations (10, 25, and 50 mg/mL) and pH values ranging from 4.0 to 9.0 by small angle X-Ray scattering (SAXS) in order to evaluate how the protein-protein interaction changes in crowding environments. Data were analyzed by means of the Global Fitting procedure, with the protein form factor calculated from human serum albumin (HSA) crystallographic structure; the interference function was described considering repulsive and attractive interaction potentials within a random phase approximation. SAXS data revealed that BSA maintains its native state from pH 4.0 up to 9.0 at all investigated concentrations. Further, the surface charge number per BSA is quantified to 10(2), 8(1), 13(2), 20(2), and 26(2) for pH values of 4.0, 5.4, 7.0, 8.0, and 9.0, respectively, showing a nice interplay between repulsive and attractive forces. In fact, the attractive potential diminishes as BSA concentration increases. The coexistence of monomers and dimers is observed at 50 mg/mL and pH 5.4, near the BSA isoelectric point. The results are discussed in the light of the interaction between proteins and polyelectrolytes.

Yan Levin (UFRGs, Brazil): Introduction to statistical mechanics of charged systems
The lectures will provide students with basic tools necessary to study thermodynamics of Coulomb systems. I will restrict myself to simple models and techniques, which nevertheless, when used correctly can give a clear insight into the fundamental physics behind various complex phenomena that appear when the interactions between the system’s constituents are dominated by the long-ranged Coulomb force.
The topics will cover the Debye-Hückel theory, Bjerrum cluster formation, phase transitions in the Restricted Primitive Model (RPM), Kosterlitz-Thouless metal-insulator transition in 2D, and charge renormalization in colloidal systems. For background, students may consult references [1] and [2].

[1] Y. Levin, Electrostatic correlations: from plasma to biology, Rep. Prog. Phys. 65, 1577 (2002).
[2] Y. Levin, Introduction to Statistical Mechanics of charged systems, Braz. J. Phys. 34, 1158 (2004).

João Ruggiero Neto (UNESP-Rio Preto, Brazil): Electrostatic and non-electrostatic features in the interaction of lytic peptides with model membranes
The adsorption of cationic peptides in anionic model membranes assessed by different experimental techniques will be presented. Electrostatic features of these interactions such as charge regulation, effect of the charges of N-terminus of the peptides, lipid segregation and the effect of the peptides on the expanded-liquid to condensed-liquid phase transition in lipid monolayers will be discussed as well as the additivity of the electrostatic and hydrophobic free energies.

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Poster Presentation: Participants who are presenting poster MUST BRING THE POSTER PRINTED. The poster size should be at most 1,5m x 1m. Please do not bring hanging banner, only sticking poster.

Project discussions: The idea is to bring your research project to be discussed with the lecturers.

BOARDING PASS: All participants, whose travel has been provided or will be reimbursed by the institute, should bring the boarding pass upon registration, and collect an envelope to send the return boarding pass to the institute.

List of Participants: Updated on March 2

General Information: General Information Sheet - Useful information specially for those who are not from São Paulo.

Accommodation: Participants whose accommodation has been provided by the institute will stay at  The Universe Flat. Each participant whose accommodation has been provided by the institute has received the details on the accommodation individually by email.

Emergency number: 9 8233 8671 (from São Paulo city); +55 11 9 8233 8671 (from abroad), 11 9 8233 8671 (from outside São Paulo).

Ground transportation instructions: 

Ground transportation from Guarulhos Airport to The Universe Flat

Ground transportation from Congonhas Airport to the Universe Flat

Ground transportation from The Universe Flat to the institute