Intézeti szeminárium
Intézeti szeminárium
2024/2025 tavaszi szemeszter (spring semester)
13 February (Thursday) 15:00, Gróh auditory (062)
I. Physikalisches Institut, Universität zu Köln, Germany
Investigating molecular ions with leak-out-spectroscopy
Leak-out-spectroscopy (LOS) is a rather novel ion-trap-based action spectroscopy method. LOS exploits the fact that vibrational energy of a laser-excited ion can be converted into kinetic energy in a collision with a suitable neutral molecule or atom. The ions are thus accelerated and may leave the trap towards a detector. By counting the "leaked-out" ions as a function of the laser wavelength, a spectrum is generated. The invention of LOS has boosted the spectroscopy of molecular ions, as it is a universal and very sensitive technique.
In this presentation, I will focus on the application of LOS to astrophysically relevant cations, in particular on exotic ions consisting of only helium and hydrogen. Such systems are also interesting because they are few-particle-systems and therefore serve as a testing ground for high-level theoretical He-He+-He and D2He+!
27 February (Thursday) 15:00, Gróh auditory (062)
Faculty of Chemistry and Chemical Technology, University of Ljubljana, Slovenia
Papain-like peptidases – allostery, oligomerization and protein engineering
Papain-like cysteine peptidases, called cysteine cathepsins in animals, are predominantly monomeric, single-domain endopeptidases with a broad substrate specificity. In recent decades, several human cathepsins have been associated with various diseases, and their inhibition has been explored as a potential treatment, albeit with limited success. These seemingly simple enzymes have been shown to have sophisticated regulatory mechanisms. We have shown that some, e.g. cathepsin K, can be allosterically regulated by polyanionic polymers such as glycosaminoglycans as well as by small molecule effectors, and molecular dynamics simulations have shown that effectors stabilise pre-existing conformations of the active site. We have also extended our work to cathepsin C, which is an exception in the family as it is a homotetramer and not a monomer. It showed similar susceptibility to small molecule effectors as the monomeric enzymes, but otherwise no additional behaviour that depends on its oligomeric state, such as cooperativity. Interestingly, a recombinant monomeric variant of the enzyme had nearly identical functional properties to the tetramer. Based on these results and the biotechnological potential of these enzymes, we are continuing our research to improve them through protein engineering. Our goal is to produce oligomeric variants with improved functional properties, such as cooperativity. To this end, we have also developed a novel system for the detection of protein homodimerization in Escherichia coli, which is currently being tested for use in protein engineering and drug discovery.
6 March (Thursday) 15:00, Gróh auditory (062)
Institute of Chemistry, Faculty of Science, Pavol Jozef Šafárik University in Košice, Slovakia
Development of green analytical procedures
The aim of this presentation is to summarize the developments in the field of green analytical chemistry at the Department of Analytical Chemistry of the P.J. Safarik University in Kosice. We will focus on the following questions: Green chemistry principles vs Green analytical chemistry (GAC) principles; How to satisfy the GAC? Important components of analytical procedures in the aspect of GAC. Practical consequences of GAC principles for selected parameters of analytical process. Milestones in GAC. Application of the liquid drop in analytical chemistry. Sample pre-treatment. Conventional liquid–liquid extraction (LLE) vs liquid-phase microextraction (LPME). Main categories of LPME, advantages and limitations. Dispersive liquid-liquid microextraction (DLLME), evolution, factors affecting DLLME/DLPME, advantages, disadvantages, problems, limitations of the technique. Various modes of DLLME. DLLME vs DLPME. Acronyms. Automation. Coupling of DLLME to detection techniques. Single drop microextraction (SDME). Application of the optical probe in analytical chemistry. Application of green solvents (deep eutectic solvents). Green metrics.
20 March (Thursday) 15:00, Gróh auditory (062)
Fachdidaktikzentrum Chemie, Univestität Graz, Austria
Communicating, Experiencing and Understanding Chemistry – Science Communication Between Outreach and Education
Science communication takes many forms—from public events to social media—but how effective are these approaches in reaching and educating school students? While universities are highly active in public engagement, do these efforts truly reach young audiences? What role do social media play, and where does real learning happen? I will discuss insights from our projects and their impact, focusing on the Chemical Christmas Lecture and social media outreach. Using the GlacierXperience project as an example, I will also highlight how out-of-school learning can be designed to engage students with current scientific topics, provide information, and give a glimpse into actual scientific research.
This talk invites a discussion on how we can bridge the gap between outreach and education—ensuring that science communication not only inspires but also fosters deeper understanding.
3 April (Thursday) 15:00, Gróh auditory (062)
Circular Chemicals at MOL Group, Hungary
Circular Chemistry at MOL
24 April (Thursday) 15:00, Gróh auditory (062)
Institute of Biohemistry, ETH Zürich, Switzerland
From SARS-CoV-2 membrane proteins to protein-RNA phase separation – how can we use multi-faceted bioNMR spectroscopy as a Swiss-knife?
BioNMR spectroscopy is a powerful and versatile tool for exploring the structure, dynamics, and interactions of biomolecules. In this talk, I will illustrate its broad applications through recent studies on viral membrane proteins and biomolecular phase separation.
First, I will present solid-state NMR investigations of SARS-CoV-2 accessory membrane proteins, highlighting their structural features, oligomerization, and potential interactions with host proteins. These findings provide insights into their roles in viral pathogenicity.
Second, I will discuss how solution-state NMR reveals the molecular mechanisms underlying protein-RNA phase separation, a key process in cellular organization. By examining the phase behavior of hnRNPC1 and its interactions with RNA, we gain a deeper understanding of ribonucleoprotein assembly and function.
These examples showcase how advanced NMR techniques can address fundamental questions in structural biology and biophysics, offering a molecular-level perspective on complex biochemical phenomena.
8/9 May (Thursday, Friday) - TBD
Chemistry – Quantum Theory Project, University of Florida, USA
TBA – Honorary Professorship Lecture on Pázmány or Eötvös Day
22/23 May (Thursday, Friday)
TBA – Science and Report Day Lecture(s)
29 May (Thursday) 15:00, Gróh auditory (062)
Department of Chemistry, The George Washington University, Washington, USA
Metabolomics of Single Cells in their Natural Environment
In multicellular organisms, cells assemble into tissues with specific functions. Tissue embedded cells operate a selection of metabolic pathways for the synthesis and degradation of a collection of small molecules that serve growth, signaling, and reproduction. Capturing the spatiotemporal distributions of metabolites, including lipids, with cellular granularity gives new insight into the functioning of tissues. We have developed ambient ionization techniques for mass spectrometry (MS) that can report on the metabolite content of functioning cells with high throughput and targeting capabilities. Image analysis and morphometry of brightfield and fluorescence microscope images are used to target selected cell types, followed by mid-IR laser ablation of individual cells. The ablation plume is ionized by an electrospray (laser ablation electrospray ionization, LAESI). Ion mobility separation (IMS) of the produced ions is followed by time-of-flight or Fourier transform ion cyclotron resonance MS for the determination of cellular metabolite abundances. Cell-type specific small molecule compositions are determined and correlated with active metabolic pathways characteristic to cellular functions. Metabolite abundance distributions reflect population heterogeneity through metabolic noise levels and reveal hidden cellular phenotypes segregated into subpopulations functioning in specific metabolic states. Examples of spatial metabolomics are presented for various cell types including human hepatocytes, Arabidopsis thaliana and onion epidermal cells, and root nodule cells of soybean in nitrogen fixing symbiosis with rhizobia.
2024/25 őszi szemeszter (autumn semester)
October 2. (Wednesday) 15:00, Ortvay auditory (0.81)
Lehrstuhl für Organische Chemie II, Ruhr-University Bochum, Germany
Preparation and Spectroscopic Characterization of Interstellar Relevant Imine Species
Simple imines are frequently used as building blocks in the synthesis of more complex molecules. In solution imines are typically prepared from carbonyl compounds and ammonia or primary amines, respectively. The simplest aldimine, formaldimine (H2CNH), has been discovered in space but cannot be isolated on Earth due to polymerization or oligomerization when concentrated. Aldimine building blocks play a key role in the formation of biorelevant molecules like amino acids or nucleobases in prebiotic chemistry. However, spectroscopic data of the compound class are rare or missing at all due to their high reactivity and the absence of molecular precursors for an on-demand mild generation. The overall goal of this project is to learn more about interstellar and prebiotic imine chemistry and characterize often proposed but yet elusive imine species.
1,2-Diiminoethane was photochemically prepared from explosive 1,2-diazidoethane in solid argon at 3 K and characterized by infrared and UV/Vis spectroscopy. In aqueous solution the simplest diimine serves as a fundamental building block for imidazole heterocycles.
The simplest α-imino acid, namely glycine imine, was prepared by UV irradiation of azidoacetic acid in solid argon at 3 K and characterized by IR and UV/Vis spectroscopy. In aqueous solution at higher concentrations glycine imine undergoes self-reduction to glycine by oxidative decarboxylation chemistry. The imine serves a critical intermediate in prebiotic amino acid synthesis.
2-Iminoacetaldehyde was proposed as an interstellar molecule and prepared by photolysis of 2-azidoacetaldehyde in solid argon at 3 K and low density amorphous water ice. The imine was characterized by characterized by infrared and UV/Vis spectroscopy.
References
[1] A. K. Eckhardt Chem. Commun. 58, 8484–8487 (2022).
[2] V. Paczelt, R. C. Wende, P. R. Schreiner and A. K. Eckhardt Angew. Chem Int. Ed. 62, e202218548 (2023).
[3] V. D. Drabkin, V. Paczelt and A. K. Eckhardt Chem. Commun. 59, 12715–12718 (2023).
October 16. (Wednesday) 15:00, Ortvay auditory (0.81)
Univ. Prof. Dr. Hinrich Grothe
TU Wien, Institute of Materials Chemistry, Getreidemarkt 9/BC, 1060 Vienna, Austria
The efficiency of ice-nucleating macromolecules from Betula pendula pollen
Various aerosols, including mineral dust, soot, and biological particles, can act as ice nuclei, initiating the freezing of supercooled cloud droplets. Cloud droplet freezing significantly impacts cloud properties and, consequently, weather and climate. Some biological ice nuclei exhibit exceptionally high nucleation temperatures close to 0 °C. Ice Nucleating Macromolecules (INMs) found on pollen are typically not considered among the most active ice nuclei. Still, they can be highly abundant, especially for species such as Betula pendula, a widespread birch tree species in the boreal forest. Recent studies have shown that certain tree-derived INMs exhibit ice nucleation activity above ‒10 °C, suggesting they could play a more significant role in atmospheric processes than previously understood. Our study reveals three distinct INM classes active at ‒8.7 °C, ‒15.7 °C, and ‒17.4 °C are present in Betula pendula. Freeze-drying and freeze-thaw cycles noticeably alter their ice nucleation capability, and the results of heat treatment, size, and chemical analysis indicate that INM classes correspond to size-varying aggregates, with larger aggregates nucleating ice at higher temperatures in agreement with previous studies on fungal and bacterial ice nucleators. Our findings suggest that Betula pendula INMs are potentially important for atmospheric ice nucleation because of their high prevalence and nucleation temperatures.
November 14. (Thursday) 15:00, Bruckner auditory (063)
Cardiff University, UK
How far can we go with single-configuration quantum chemistry?
Traditional quantum chemistry begins with the mean field model, where the orbital approximation leads to a single Slater determinant. Electron correlation effects are then introduced perturbationally, or through coupled-cluster theory, or modelled with a density functional. When correlation is strong, multiconfigurational reference methods offer a general flexible approach that avoids the qualitative failure of the Hartree-Fock reference, but they have the disadvantages of strong cost scaling with system size, and, in most cases, a lack of size extensivity. In this lecture I will explore the extent to which the useful domain of single-reference methods can be extended. The consideration will include alternative coupled-cluster formulations, new forms of perturbation theory, and extension to the correlation of electrons with vibrations (beyond Born-Oppenheimer) and photons (molecules in an optical cavity).
November 20. (Wednesday) 15:00, Ortvay auditory (0.81)
Department of Physics and Astronomy, University College London, London, UK
Enhanced Sampling Simulations of Biomolecular Systems
Phosphate catalytic enzymes are essential and ubiquitous to all forms of life. While structures of these proteins are typically readily available, prediction and design of their function and activity is a key current challenge. Here we present computing intensive free energy calculation data and machine learning applications to predict catalytic activity for prototype examples including Ras [1]. Our work highlights the important role of coupled proton transfer steps in the catalytic mechanism using the finite-temperature string method. This allows us to use multiple collective variables that govern the reaction path. Identification of these collective variables in complex processes presents a major problem. We offer promising AI-driven algorithms to help identify essential reaction coordinates in biomolecular processes [2,3].
References
[1] Berta, D.; Gehrke, S.; Nyíri, K.; Vértessy, B. G.; Rosta, E. Mechanism-Based Redesign of GAP to Activate Oncogenic Ras. JACS, 2023, 10.1021/jacs.3c04330.
[2] Badaoui, M.; Buigues, P. J.; Berta, D.; Mandana, G. M.; Gu, H.; Földes, T.; Dickson, C. J.; Hornak, V.; Kato, M.; Molteni, C.; Parsons, S.; Rosta, E. Combined Free-Energy Calculation and Machine Learning Methods for Understanding Ligand Unbinding Kinetics. J. Chem. Theory Comput. 2022, 10.1021/acs.jctc.1c00924.
[3] Buigues, PJ; Gehrke, S; Badaoui, M; Mandana, G. M.; Qi, T; Bottegoni, G; Rosta, E. Investigating the Unbinding of Muscarinic Antagonists from the Muscarinic 3 Receptor. bioRxiv; 2023, 10.1101/2023.01.03.522558.
December 4. (Szerda) 15:00, Ortvay terem (0.81)
Kiss László, Széchenyi- és Prima Primissima-díjas csillagász
HUN-REN Csillagászati és Földtudományi Központ
Horgosról a csillagokig és tovább ‒ egy csillagász kalandozásai a nagyvilágban
Előadásomban bemutatom, hogyan válhat egy horgosi kisdiákból nemzetközileg elismert csillagász szakember, intézményvezető tudománymenedzser és egyben a média által kedvelt ismeretterjesztő tudós. Milyen impulzusok értek a falusi ég alatt, az inspiráló középiskolában és végül az egyetemen, ahol végképp eldőlt a szakmai sorsom? Mi kell ahhoz, hogy valaki helyt álljon bárhol a világban? Az életút mellett kitérek friss kutatásaimra a Naprendszerben és a más csillagok körül keringő bolygórendszerekben, földi és űrtávcsöves megfigyeléseken alapuló vizsgálataimra. Továbbá megosztom tapasztalataimat arról is, hogy a 21. században milyen módszerekkel lehet hatékonyan közvetíteni a tudományt, és hogyan kelthetjük fel az emberek, különösen a fiatalok érdeklődését a tudomány szépségei iránt.