Conference Schedule

Day1: March 15, 2018

Keynote Forum

Biography

Holger Stark has studied biochemistry and completed his PhD at the age of 29 years from the Free University Berlin, Germany. After a short postdoc at Imperial College in London (UK) he became a group leader at Marburg University (Germany) and moved from there to the Max-Planck-Institute in Goettingen (Germany) where he later became a director in 2015. He has over 100 publications and an H-index of 45.


Abstract

Single particle cryo electron microscopy (cryo-EM) has developed into a powerful technique to determine 3D structures of large macromolecular complexes. Due to improvements in instrumentation and computational image analysis, the number of high-resolution structures is steadily increasing. The method cannot only be used to determine high-resolution structures but also to study the dynamic behavior of macromolecular complexes and thus represents a very complementary method to X-ray crystallography. We have recently determined the structure of human proteasomes and their inhibition by anti-cancer drugs using X-ray crystallography to visualize the chemistry of inhibition at unprecedented resolution of 1.8 Å. By cryo-EM we were able to visualize the long-range allosteric conformational changes induced by the drug binding and visualized the effects of drug binding in terms of restrictions in the free-energy landscape of the human 26S proteasome. More examples of cryo-EM studies of dynamic processes in large macromolecular complexes will be presented at the conference.

Biography

B. Montgomery Pettitt is Robert A. Welch Distinguished University Chair of Chemistry at the University of Texas Medical Branch. He was a postdoctoral fellow at the University of Texas at Austin and an NIH Fellow at Harvard University. His research focuses on understanding molecular recognition of biopolymers in solution. Molecular recognition be it intermolecular between two species or intramolecular such as folding, underlies the mechanisms of biochemistry. This theoretical work relies on techniques in statistical mechanics and high performance scientific computing.


Abstract

The elastic properties of DNA molecules are sensitive to environment. DNA is often double stranded and occasionally knotted but must open to for replication, repair, transcription and recombination. On opening the elastic persistence length changes by over two orders of magnitude. The interface between surfaces or proteins and nucleic acids changes the properties of DNA. Interfaces offer large electrostatic fields and density gradients changing the local free energy surface and therefore form a challenging set of problems in current design issues. We consider examples of both DNA minicircles used as artificial vectors and phage packing. Our models describe aspects of sequence and target length dependence important in protein recognition.

 

Tracks

  • Biophysics | Multi Scale Modelling Simulation & Molecular Graphics | Computational Chemistry
Location: SilverStone

Richard Neutze

University of Gothenburg, Sweden

Chair

Biography

Richard Neutze took his PhD in Physics in 1995 from the University of Canterbury (New Zealand). He was introduced to Molecular Biophysics at Oxford University (England); completed a Postdoc at Tübingen University (Germany); and then moved to Uppsala University (Sweden). In 1998, he became Assistant Professor at Uppsala University and he moved his group to Chalmers University of Technology in 2000. In 2006, he was appointed Professor of Biochemistry at the University of Gothenburg. He has worked on the structural biology of aquaporins; bacterial rhodopsins; photosynthetic reaction centres; and time-resolved diffraction and time-resolved wide angle X-ray scattering studies of membrane proteins, using both synchrotron radiation and X-ray free electron lasers.

 


Abstract

X-ray free electron lasers (XFEL) provide a billion-fold jump in the peak X-ray brilliance when compared with synchrotron radiation. One area where XFEL radiation has an impact is time-resolved structural studies of protein conformational changes. This presentation will describe how we used time resolved serial femtosecond crystallography at an XFEL to probe light-driven structural changes in bacteriorhodopsin. Bacteriorhodopsin is a light-driven proton pump which has long been used as a model system in biophysics. The mechanism by which light-driven isomerization of a retinal chromophore is coupled to the transport of protons “up-hill” against a transmembrane proton concentration gradient involves protein structural changes. Collaborative studies performed at SACLA (the Japanese XFEL) have probed structural changes in microcrystals on a time-scale from nanoseconds to milliseconds. Structural results from these studies enabled a complete picture of structural changes occurring during proton pumping by bacteriorhodopsin to be recovered.

Biography

Joze Grdadolnik completed his PhD at the National Institute of Chemistry (NIC), Slovenia. He spent a year and a half at Yves Maréchal’s lab in Grenoble, France for his Postdoc. Currently he is employed as a Researcher at NIC. He has published over 60 papers in scientific journals. His publication H-index is 24. The application of vibrational spectroscopy (infrared, Raman and VCD) to determine the structure and dynamics of biomolecules is the central topic of his scientific interest. Two topics may be highlighted; the first topic is associated to the structural studies of dipeptides in water. They showed that the intrinsic backbone preferences are already determined at the dipeptide level. The second topic is attributed to the structural study of water molecules in the vicinity of fully nonpolar solutes. They have proven the hypothesis that nonpolar molecules induce the formation of stronger hydrogen bonds in layers close to solutes.


Abstract

Hydrophobicity plays an important role in numerous physico-chemical processes, from the process of dissolution in water to protein folding, but its origin at the fundamental level is still unclear. The classical view of hydrophobic hydration is that in the presence of a hydrophobic solute, water forms transient microscopic ‘icebergs’ arising from strengthened water hydrogen bonding, yet there is no experimental evidence for enhanced hydrogen bonding and/or ‘icebergs’ in such solutions. We have used the redshifts and line-shapes of the isotopically decoupled infrared O-D stretching mode of small, purely hydrophobic solutes (methane, ethane, krypton, xenon) in water to study hydrophobicity at the most fundamental level. We will present the first unequivocal and model-free experimental proof for the presence of strengthened water hydrogen bonds near four hydrophobic solutes, matching those in ice and clathrates. The water molecules involved in the enhanced hydrogen bonds display extensive structural ordering resembling that in clathrates. The number of ice-like hydrogen bonds is 10 to 15 per methane molecule. Ab initio molecular dynamics simulations have confirmed that water molecules in the vicinity of methane form stronger, more numerous and more tetrahedrally oriented hydrogen bonds than those in bulk water, and that their mobility is restricted. We demonstrate the absence of intercalating water molecules that cause the electrostatic screening (shielding) of hydrogen bonds in bulk water as the critical element for the enhanced hydrogen bonding around a hydrophobic solute. Our results confirm the classical view of hydrophobic hydration.

Biography

Stefan Bibow since Jan 2017 is a project leader at the Biozentrum of the University of Basel (as an Ambizione fellow). From Sep 2012 – Dec 2012   was a scientific visitor at the Salk Institute, La Jolla, USA. He was a Postdoctoral fellow from Jan 2012 – Dec 2016 at ETH Zurich, Switzerland. He completed his PhD at Max Planck Institute for Biophysical Chemistry, Göttingen, Germany in August 2011. He did his Diploma in Biophysics, Humboldt University of Berlin, Germany in May 2007. He has done his Matriculation for Biophysics at the Humboldt University of Berlin in October 2001.    


Abstract

High-density lipoprotein particles (HDLs) are transport containers in the circulatory system that receive cellular cholesterol and lipids destined for the liver and other lipoprotein particles. Because low levels of HDL-cholesterol often indicate an increased risk for cardiovascular diseases, HDL particles are considered as important pharmacological targets for therapeutic strategies. Mature spherical HDLs develop from lipid-free apolipoprotein apoA-I through the formation of intermediate discoidal HDL particles which are the primary acceptors of cellular cholesterol. Although of high biophysical and medical importance heterogeneity in density, size, shape, as well as protein and lipid composition prohibited a detailed molecular and structural description of discoidal HDL particles. Here, we present the three-dimensional solution structure of reconstituted discoidal HDL (rdHDL) particles by combining nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR) and transmission electron microscopy (TEM) data. By using amino acid selective labeling, methyl labeling, Lipid-PREs and long-range EPR data we found that rdHDL particles are composed of two helical apoA-I molecules that dimerise in an anti-parallel fashion to form a double belt around a lipid bilayer patch. The integrity of this unique structure is maintained by up to 28 salt bridges and an unusual zipper-like pattern of cation-π interactions between helices 4 and 6. In order to accommodate a hydrophobic interior a gross ‘right to right’ rotation of the helices upon lipidation is necessary. The structure relevant in our understanding of HDL-biology and metabolism reflects thereby the beauty and complexity of this type of biological shuttling container that is able to hold a fluid lipid/cholesterol interior at a protein lipid ratio of 1:50.

Biography

J.-M. Jault (PhD) is a research director of the CNRS and is the Director of the “Molecular Microbiology and Structural Biochemistry” research unit (UMR5086) in Lyon (since January 2016). He is also a team leader in the same unit. He has a strong expertise in the biochemical characterization of various families of ATPases, GTPases and protein kinases. He has been working on ABC transporters for 20 years and has contributed to the identification, overexpression, purification and biochemical/biophysical characterization of several bacterial multidrug transporters leading to a better understanding of the functioning mechanism of these transporters. He published 78 peer-reviewed articles (2524 citations and h-factor of 28, Web of Science) and has one patent. He has been elected twice as a member of the ‘National Committee of Scientific Research’ (CoNRS) in the discipline of ‘Molecular and Structural Biology, Biochemistry’ (2012-2016 and 2016-2020).


Abstract

ABC (“ATP-Binding Cassette”) transporters can translocate a huge variety of molecules across a membrane by coupling transport with ATP hydrolysis. They are found in all living organisms and some members of this superfamily are involved in resistance to many unrelated compounds (e.g. antibiotics, anticancerous, antifungal…) and thus confer a multidrug resistance phenotype. Our studies focus on BmrA (“Bacillus multidrug resistance ATP”), a prototypical bacterial multidrug ABC transporter from Bacillus subtilis which is homologous to the human P-glycoprotein involved in resistance of cancerous cells to therapeutic drugs.

Using both H/D exchange and solid-state NMR, we were able to probe major conformational differences between the resting state (inward-facing conformation) and the ATP-bound state (outward-facing conformation) of BmrA, either in a solubilized detergent form or reconstituted in lipids. Our results highlight the important changes in flexibility and conformation between these two states of the catalytic cycle of BmrA, and the flexibility observed in the resting state could possibly widen the specificity for drug recognition.

Biography

Artur Góra received his PhD degree in Chemistry in 2002 from the Jagiellonian University in Poland. In 2004 he was awarded a JSPS Fellowship, and from 2004 to 2006 he was working at the National Institute of Advanced Industrial Science and Technology in Japan. From 2010 to 2013, he has been a Marie Curie Fellow at the Loschmidt Laboratories of the Masaryk University in Brno, Czech Republic. He is a Leader of Tunneling Group focused on Protein Engineering, Drug Design and Software Development, facilitating molecular dynamic simulations results analysis and interpretation. Since 2016, he is the Vice Director of Biotechnology Centre, Silesian University of Technology in Poland.


Abstract

In past years, several tools for porous, tunnels and pathways identification in macromolecules were developed. The most recent ones like CAVER 3.0 or Mole 2.0 can facilitate analysis of molecular dynamic (MD) simulations and allow gathering precise information about the geometry of detected pathways and their prolongation in time. However, the mentioned methods use a spherical probe for tunnels exploration, thus providing an approximation of tunnels to tubes with symmetrical diameter instead of real tunnel picture. Moreover, the knowledge of geometrical properties of existing tunnels can only suggest ways of solvent or ligands molecules entry/exits. It is hard to estimate what are the major factors controlling the solvent flow: tunnel diameter, the length of the tunnel and the properties of amino acids that build the tunnel. It is also unclear how long the tunnel needs to be detected as an open one to provide access for the desired molecule. In principle, MD simulations provide such information. Simulated protein is immersed in water box and during the entire simulation, water molecules penetrate the protein core. However, the identification and tracking of water molecules which enter regions important for catalysis, require screening of position of thousands dozens of single molecules along several thousands of MD steps. To facilitate analysis of the behaviour of water (and if necessary other solvent molecules or ligands), we have developed AQUA-DUCT. Here we would like to provide an example of its usage for analysis of water transportation in selected enzymes, which allows defining the water penetration pathways directly and in an easy way distinct the substrate and water pathway.

Biography

Dr. Neva Caliskan pursued her Master`s and doctoral studies at the Max Planck Research School for Molecular Biology in Göttingen. Thereafter she stayed in Göttingen as a post doctoral researcher and later as a project leader at the Max Planck Institute for Biophysical Chemistry in the department of Physical Biochemistry. Her research focuses on characterization of unusual translation events, particularly ribosome frameshifting by using rapid kinetic analysis tools. From 2018 onwards she is appointed as a group leader at the Helmholtz Institute for RNA-based Infection Biology in Würzburg.


Abstract

Ribosome frameshifting during translation of bacterial dnaX can proceed via different routes, generating a variety of distinct polypeptides. Using kinetic experiments, we show that –1 frameshifting predominantly occurs during translocation of two tRNAs bound to the slippery sequence codons. This pathway depends on a stem-loop mRNA structure downstream of the slippery sequence and operates when aminoacyl-tRNAs are abundant. However, when aminoacyl-tRNAs are in short supply, the ribosome switches to an alternative frameshifting pathway that is independent of a stem-loop. Ribosome stalling at a vacant 0-frame A-site codon results in slippage of the P-site peptidyl-tRNA, allowing for –1-frame decoding. When the –1-frame aminoacyl-tRNA is lacking, the ribosomes switch into –2 frame. Quantitative mass spectrometry shows that the –2-frame product is synthesized in vivo. We suggest that switching between frameshifting routes may enrich gene expression at conditions of aminoacyl-tRNA limitation.

Biography

Mauro Lapelosa holds a PhD from Rutgers University, USA. He is a Senior Postdoc at the Italian Institute of Technology. He has 15 publications, and his publication H-index is 10. He has been serving as a reviewer of many reputed journals.


Abstract

The interaction between the MEEVD C-terminal peptide from the heat shock protein 90 (Hsp90) and tetratricopeptide repeat A (TPR2A) domain of the heat shock organizing protein (Hop) represents a useful model to study peptide-protein interaction in general. In this work, the mechanism of binding is inferred and the potential of mean force is calculated using the adaptive biasing force (ABF) methodology. Conformational changes of the peptide and the protein receptor induced by binding are observed. The binding free energy is about-8.4 kcal/mol which reproduces the experimental data. The simulations show several transitions from the bound to unbound state along a pathway connecting the binding pocket to the solvent. The MEEVD peptide slowly unbinds breaking the hydrogen bonds first, then moving on the side while interacting with the side chain of residue Asp 5 of the peptide. After this initial movement, the peptide completely moves into the solvent. Analyzing binding transitions intermediate states can be found and they are characterized by the peptide interacting with a lateral helix; helix A1 of the receptor with mainly Asp 5, Val 4, and Glu 3 of the peptide. The structure of the bound complex obtained after rebinding is structurally very similar to the crystal structure of the complex (0.48 Å RMSD). Structural modeling and energetic analysis of the protein E of dengue has been performed to better understand the interaction of DII E (60aa-250aa), an important epitopic region, and the EDE1 C8 antibody. Molecular dynamic runs of the complex have been performed to evaluate the models. RMSF and intra-molecular interactions were used to evaluate the stability of the structural models.

Day2: March 16, 2018

Keynote Forum

Biography

Salvador Ventura is Full Professor and Head of the Protein Folding and Conformational Diseases Laboratory at Universitat Autònoma de Barcelona. Work at his lab focuses on protein folding, misfolding and amyloid formation, with special emphasis on their impact on protein homeostasis and conformational disorders. He has contributed with more than 170 research articles to these topics. He has been a Postdoctoral Fellow at EMBL-Heidelberg and visiting scientist at Harvard Medical School (US) and Karolinska Institutet (Sweden). 


Abstract

Transthyretin (TTR) is a plasma homotetrameric protein implicated in fatal amyloidosis. TTR tetramer dissociation precedes pathological TTR aggregation. Despite TTR stabilizers being promising drugs to treat TTR amyloidoses, none of them is approved by the Food and Drug Administration (FDA). Repositioning existing drugs for new indications is becoming increasingly important in drug development. Here, we repurposed tolcapone, an FDA-approved molecule for Parkinson’s disease, as a very potent TTR aggregation inhibitor. Tolcapone binds specifically to TTR in human plasma, stabilizes the tetramer in vivo and inhibits TTR cytotoxicity. In contrast to most TTR stabilizers, it exhibits high affinity for both TTR thyroxine-binding sites. The crystal structure of tolcapone-bound TTR explains why this molecule is a better amyloid inhibitor than tafamidis, so far the only drug in the market to treat the TTR amyloidoses. Overall, tolcapone, already in clinical trials, is a strong candidate for therapeutic intervention in these diseases.

Biography

Caillet-Saguy C studied Biochemistry and obtained her PhD at Paris Diderot University (Paris7). Her thesis made in the NMR unit at the Institut Pasteur focused on the study of heme acquisition mechanism in bacteria. She used biophysical approaches, mainly nuclear magnetic resonance. She joined the team of Biocrystallography led by Stéphane Bressanelli in the Molecular and Structural Virology Unit (France) for a 3-year Postdoc. Her project focused on the study of genome replication of hepatitis C virus. She acquired a dual expertise in NMR and X-ray crystallography. Then she joined the team of Nicolas Wolff at the Institut Pasteur. She is interested in disturbance by viruses of the signalling pathways of the infected cell involving PDZ domains. In 2014, she became an Assistant Professor. Her work has resulted in 14 peer-reviewed publications and 12 presentations as speaker in conferences. Her publication H-index is 10.


Abstract

The human PTPN4 belongs to the protein tyrosine phosphatase (PTP) family. PTPN4 contains an N-terminal FERM, a central PDZ domain and a C-terminal PTP domain. PTPN4 protects cells against apoptosis and targeting its PDZ domain abrogates this protection .We documented the regulatory mechanisms of PTPN4 and showed that the PDZ domain inhibits the phosphatase activity of PTPN4 and that the mere binding of a PDZ ligand is sufficient by itself to release catalytic inhibition. The PDZ-PTP supramodule adopts a compact conformation in solution and the PDZ ligand disrupts transient inter-domain communication, thereby allosterically restoring the catalytic competence of PTPN4. The inter-domain linker is mandatory to this regulation of PTPN4 catalytic activity. We have recently identified that PTPN4 interacts with the MAP kinase p38γ. The C-terminus of p38γ (p38γ-Cter) targets the PDZ domain of PTPN4, promoting massive cell death of human glioblastoma upon intracellular delivery. We identified the molecular basis of the recognition of p38γ-Cter that displays the highest affinity among all endogenous partners of PTPN4 and we reported the molecular interactions in vitro between the full-length kinase and the phosphatase PTPN4.

Tracks

  • Multi Scale Modelling, Simulation & Molecular Graphics | Biophysics | 3D Protein Structure Predictions | Crystallography | Biomarkers | Analytical Techniques
Location: SilverStone

Salvador Ventura

Universitat Autònoma de Barcelona, Spain

Chair

Biography

Viviana M. completed her PhD at the age of 28 from the University of Maryland-College Park, USA. She is currently a postdoctoral scholar at the Voth Lab in the Chemistry Department at the University of Chicago. She has 10 publications, 3 as first author, and 4 more under preparation. Viviana contributed with over 10 posters and oral presentations at multiple conferences and simposia since 2013, both in the USA as well as abroad. She was born in Barcelona, Spain and grew up in Bolivia, where she has also presented her work as invited speaker at the “Universidad Mayor de San Andres” in seminar series prepared by the departments of Physics and Chemical Engineering and the IBTEN (the national regulatory institution of nuclear energy in Bolivia).


Abstract

Binding and aggregation of the HIV-1 Gag protein to the plasma membrane (PM) enable budding and release of immature virions, which enable the propagation of viral infection. The matrix (MA) domain of the Gag protein is a 131-amino-acid sequence responsible for targeting the membrane. The MA domain seems to favor electrostatic interactions at the membrane surface in places where PIP2 lipids are more abundant. The myristate group (Myr), a fatty acid covalently attached to the N-terminus of the protein, serves as an anchor once initial binding occurs. The mechanism of Myr release from its binding pocket and its insertion into the membrane is still unclear. NMR studies suggest MA trimerization facilitates Myr exposure from its sequestered conformation, leading to Myr anchoring. Using molecular dynamics and enhanced sampling techniques, such as metadynamics, we examined MA-membrane interactions with model membranes for the PM as well as MA-MA interaction and trimerization. We looked at the effect of lipid composition, specifically the presence of PIP2 and cholesterol, on MA binding events and whether membrane-binding promotes lipid reorganization and raft formation. We present the protein conformational changes that take place during Myr exposure, MA-membrane binding, and MA trimerization. Computational resources for this work were available through XSEDE (Stampede2 and Bridges) and the Anton2 machine from the Pittsburgh Supercomputing Center.

Biography

Sowmya Indrakumar holds a Bachelor of Science (by Research) and Master of Science degree in Biology from Indian Institute of Science, Bangalore, India. Throughout her undergraduate studies, she was a recipient of ‘Innovation in Science Pursuit for Inspired Research-Department of Science & Technology (INSPIRE-DST) fellowship. In 2016, she became part of the PIPPI (http://www.pippi.kemi.dtu.dk/) project as a PhD researcher at Technical University of Denmark, Denmark. This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie SkÅ‚odowska-Curie grant.


Abstract

Proteins often perform diverse and complex set of functions within the cell, including catalyzing metabolic reactions, transport of specific substances from one location to another, etc. Therefore, proteins are regularly used in protein-based therapies to treat diseases. They have numerous advantages over small molecule drugs, as human body naturally produce many of the therapeutic proteins, also called biologics. Biologics are often characterized by high specificity and potency with low toxicity, and thus have interested many pharmaceutical industries. Several challenges confront pharmaceutical scientists involved in the development of protein therapeutics. For instance, the proper stabilization of biologics is one of the major concerns. To overcome this issue, excipients play a major role in stabilizing biologics to prevent protein-protein interactions and hence aggregation. Currently, a detailed molecular understanding of the effect of different physicochemical formulation conditions on the stability of proteins are sparse as molecular interactions are difficult to investigate experimentally at the molecular level. Thus, computational approaches as applied in the current study can provide insight on the single-molecule level. 

The main objectives are to identify potential hotspots for excipient-protein interactions, to determine preferential interaction coefficients of excipients using molecular docking approaches further validated by molecular dynamics (MD) simulations. Using free energy approaches such as implicit solvent molecular mechanics (MM-PBSA) and explicit solvent linear interaction energy (LIE) methods, relative binding affinities of excipients to the proteins are predicted in order to rank excipients and to determine the effect of excipients on protein dynamics and flexibility. Additionally, independent protein MD simulations were performed and further analyzed for potential protein-excipient interaction hotspots by using a clustering method to find the most representative structures from the simulations and then applying FTMap to locate potential hotspot region for protein-excipient interactions. These results will be further supported by NMR studies.

Biography

Rajas Rao completed masters in Biological Sciences from Bangalore University, India. He worked at Prof. R. Sowdhamini's laboratory in National Centre for Biological Sciences, Bangalore, where he worked on phylogeny of a protein involved in bacterial quorum sensing, LuxS. He is currently working towards PhD degree at Inserm unit UMR-1134, on the topic of dynamics and interactions of Translocator Protein, under the guidance of Prof. Catherine Etchebest and Prof. Frederic Cadet.


Abstract

Translocator protein (TSPO) is a transmembrane (TM) protein localized in outer mitochondrial membrane. It consists of five transmembrane helices connected by loops of various lengths. TSPO has been implicated in various pathological situations that include cancer, Alzheimer's and Parkinson's diseases, malaria, inflammation, etc. Initial studies indicated that TSPO would be involved in transport of cholesterol from cytoplasm into the inner membrane of mitochondria. Furthermore, a cholesterol binding site, the so-called CRAC motif was identified. Yet, recent studies have brought contradictory results and led to revisit the actual role of TSPO. Hence, its physiological role remains still unclear.

Recent high-resolution structures of TSPO solved for different species in different conditions exhibit significant differences, which confirms that TSPO is a dynamical protein. In the present study, we examine the structural dynamics of the mouse TSPO (mTSPO) protein by means of coarse-grained and all-atom molecular dynamics simulations. As mTSPO 3D structure was only solved in the presence of the PK-11195 ligand, we address the following questions: i) what is the structure and the dynamics of the protein in the absence of the ligand ii) what is the impact of the ligand on the dynamics of the protein. Our results show that in absence of ligand TSPO is a highly dynamic protein, characterized by secondary structure deformations. These results are in very good agreement with solid-state NMR data obtained in the absence of the ligand.  In the presence of the ligand, the secondary structures are more preserved, which confirms the stabilizing effect of the ligand. However, surprisingly, the protein exhibits larger fluctuations in the loop regions when the ligand is present.  Importantly, we also identified correlated motions between TM helices that differ when TSPO is bound or not to PK-11195. Notably, this ultimately influences the dynamics of the cholesterol-binding CRAC motif. We further propose that these changes in dynamics would have impact on binding properties of TSPO, e.g. binding to cholesterol, or to other proteins that are believed to interact with TSPO as part of various physiological processes.

Biography

Hugo Muñoz Hernández completed his international PhD in Biochemistry at the age of 29 years from Univeridad Autonoma de Madrid (2017). He presented his PhD with the title “Structural biology and characterization of the human R2TP, an HSP90 co-chaperone complex”. The PhD was done in the “Centro de Investigaciones Biológicas del Consejo Superior de Investigaciones Científicas” and it was supervised by Prof. Oscar Llorca. Llorca's group has an extended collaboration with Prof. Laurence Pearl from University of Sussex. Hugo has spend time in University of Sussex. Actually, he is doing a first post-doctoral research in the Spanish National Cancer Research Centre, CNIO.


Abstract

This work has focused on the study of the structure of the human R2TP complex (hR2TP), an HSP90-co-chaperone. The R2TP complex was described for the first time in Saccharomyces cerevisiae. In this organism the complex is formed by Rvb1p, Rvb2p, Tah1p and Pih1p proteins, and these components give the name to the complex (Zhao et al, 2005). The hR2TP has a cochaperone function and interacts with the "heat shock protein 90" (HSP90) chaperone. R2TPHSP90 is involved in the biogenesis of the C/D box of small nucleolar ribonucleoprotein (snoRNP), the maturation of phosphatidylinositol-3-kinase related kinases (PIKKs) and the assembly of RNA polymerase II. How hR2TP is able to carry out the correct activation and assembly of these fundamental complexes at the cellular level is still unknown (Kakihara & Houry, 2012).The main contribution from this work is improving our knowledge about the structure of hR2TP. In humans this complex is formed by the following proteins: RuvBL1, RuvBL2, RPAP3 and PIH1D1. Subsequently, the reconstituted hR2TP was analyzed by cryo-electron microscopy. In this presentation, I will show the three-dimensional (3D) structural organization of the hR2TP complex.From the structure of hR2TP it can be determined that RuvBL1 and RuvBL2 proteins form a platform for the anchoring of RPAP3-PIH1D1. RPAP3 is fundamental in the recruitment process of the RuvBL1-RuvBL2 complex and also the HSP90 chaperone.Therefore, here is provided a first view of the structural architecture of the hR2TP complex, afirst step towards understanding important cellular processes that govern the maturation of PIKKs, telomerase and the assembly of RNA polymerase II among others.

Biography

Yamina C has completed her PhD at the age of 32 years from Oran University, ALGERIA. She is the student of Mostaganem University, Algeria. She has one publication on journal of European Chemical Bulletin “Synthesis and Antimacrobial Activity of Some New L-Lysine Glycoside Derivatives”.


Abstract

This present study investigates the batch ETL dye sorption by grape seeds. The sorbent was synthesized and characterized by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The effects of pH, initial dye concentration, contact time and mass sorbent in the efficiency of ETL sorption were investigated. Furthermore, pseudo-first and second-order kinetic models were also used to analyze sorption kinetics. The equilibrium adsorption results were fitted by the Langmuir and Freundlich isotherms. Maximum amounts of ETL removal (2.36 mg/g) was observed at pH 2, sorbent weight 500 mg and contact time 60 mins. The Langmuir model feted well the experimental data.