Monday 15.06.

8:00 PDT - 11:00 EDT - 15:00 UTC

16:00 UK - 17:00 CET - 18:00 IL

Lewis E. Kay

Department of Molecular Genetics, Biochemistry and Chemistry, University of Toronto

The important role of dynamics in the function and misfunction of molecular machines

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Protein molecules play critical roles in cellular function and they catalyze many of the biochemical reactions that are necessary for life. The three-dimensional shapes of these molecules are crucial for guiding proper function and they can change with time due to interactions with other molecules, various stresses on the cell or simply the result of random fluctuations. Although very detailed static pictures of protein molecules have been produced using traditional biophysical tools, macromolecular function and misfunction is, in many cases, intimately coupled to flexibility and knowledge of molecular motions therefore becomes critical. For the past 3 decades my laboratory has developed biophysical techniques, focusing on solution based Nuclear Magnetic Resonance spectroscopy for the study of biomolecular dynamics. A brief description of some of the methods we have derived will be given along with examples to illustrate the critical importance of dynamics to protein function and misfunction.

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Martin Gruebele

Department of Chemistry, University of Illinois at Urbana-Champaign

Protein folding and association dynamics: from in silico to in vitro to in vivo

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Protein folding and binding reactions are generally quite fast and involve small free energy differences. As a result, they can be sensitive to the environment that biases protein energy landscapes. I will discuss molecular dynamics simulations, test-tube experiments, in-cell measurements, and measurements in living animals that highlight the sensitivity of protein dynamics to its solvation environment.

Monday 29.06.

8:00 PDT -  11:00 EDT - 15:00 UTC

16:00 UK - 17:00 CET - 18:00 IL

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Monday 13.07.

8:00 PDT -  11:00 EDT - 15:00 UTC

16:00 UK - 17:00 CET - 18:00 IL

Jane Dyson

Department of Integrative Structural and Computational Biology, The Scripps Research Institute

NMR Dynamics Studies of Protein Folding Intermediates

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Jane Dyson and Peter Wright

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The transient intermediate states that are populated as a protein folds are difficult to access and study. Both kinetic and equilibrium biophysical methods have been used to probe these states, using chemically or physically unfolded and partly folded states as models. NMR gives unique information on the local motions of a protein chain. The ps-ns time scale motions of the polypeptide backbone in unfolded and partly folded states, measured using relaxation rates, can give important insights into the factors that contribute to progress along the folding pathway. In addition, we can study states at low populations within a conformational ensemble using relaxation dispersion measurements that probe ms-ms motions, which are of particular interest in the folding processes of proteins.

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Dave Thirumalai

Department of Chemistry, The University of Texas at Austin

Iterative Annealing Mechanism for GroEL

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Most cytosolic proteins fold spontaneously as envisioned by Anfinsen. However, there are number of proteins that require the chaperone machinery to reach their functionally competent states. Using theory, simple arguments, and simulations using coarse-grained models I will describe the workings of the E. Coli. chaperonin GroEL.  A framework based on the Iterative Annealing Mechanism that unifies inefficient folding under non-permissive conditions, GroEL allostery, and function will be presented.  If time permits some open problems will be discussed.

Monday 27.07.

8:00 PDT -  11:00 EDT - 15:00 UTC

16:00 UK - 17:00 CET - 18:00 IL

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Peter G. Wolynes

Department of Chemistry, Rice University

Protein Dynamics and the Brain

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The brain is a molecular computer. How the brain computes, and feels and learns and remembers remain great mysteries. Neurobiologists have, however, identified some key protein actors in the mechanisms of learning and memory. I will describe some theoretical and computational efforts in understanding some of the molecular aspects of 1) Hebbian learning through the regulatable assembly of the actin cytoskeleton in dendritic spines, 2) the hypothesis that long-term memory involves a functional prion protein and 3) some aspects of the physical chemistry of aggregation processes that are involved in the pathogenesis of Huntington’s disease and Alzheimer’s disease. 

Monday 10.08.

8:00 PDT -  11:00 EDT - 15:00 UTC

16:00 UK - 17:00 CET - 18:00 IL

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YouTube: https://www.youtube.com/watch?v=-rA86LgToxI

Robert T. Sauer

Department of Biology, Massachusetts Institute of Technology

Protein recognition, unfolding, and translocation by the AAA+ ClpXP protease

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ClpX is a AAA+ unfoldase and translocase that works with the ClpP peptidase to perform ATP-dependent degradation of target proteins in organisms from bacteria to mammals. I will discuss cryo-EM structures of ClpXP with bound substrates, biochemical experiments, and single-molecule optical-trapping studies that provide insight into ClpXP mechanism.

Monday 24.08.

8:00 PDT -  11:00 EDT - 15:00 UTC

16:00 UK - 17:00 CET - 18:00 IL

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Taekjip Ha

Department of Biophysics, Johns Hopkins University

Conformational Control: From Single Molecules to Biotechnologies

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Cellular functions of biological molecules are often controlled through conformational switching mediated by protein phosphorylation and protein-protein interactions. Single molecule biophysical studies of bacterial enzymes that unwind DNA in an ATP-dependent and ATP-independent manner taught us how their functions are controlled by conformational switching. We exploited these conformal control mechanisms to create new enzyme behaviors suitable for biotechnological applications (rapid pathogen detection, accurate genome-editing and genome imaging,…) and for new research avenues (co-transcriptional RNA folding, very fast DNA repair studies,…).

Monday 07.09.

8:00 PDT -  11:00 EDT - 15:00 UTC

16:00 UK - 17:00 CET - 18:00 IL

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Matthias Rief

Department of Physics, Technical University Munich

Forces in Chaperone-Mediated Protein Unfolding and Cell Adhesion

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Many process in our cells are mechanical. Single molecule methods allow studying the forces involved in those processes. In my talk I will discuss 2 examples. In the first part, I will show how the concerted action of the hsp70 chaperone and its co-chaperones completely unfold the glucocorticoid receptor. In the second part of my talk, I will discuss how the cytoskeletal proteins talin and kindlin co-operate to strengthen their mechanical bond to the cell adhesion protein integrin.

Monday 21.09.

8:00 PDT -  11:00 EDT - 15:00 UTC

16:00 UK - 17:00 CET - 18:00 IL

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Monday 05.10.

8:00 PDT -  11:00 EDT - 15:00 UTC

16:00 UK - 17:00 CET - 18:00 IL

Susan Marqusee

Department of Molecular and Cell Biology, University of California Berkeley

Modulation of the Energy Landscape by Cellular Factors

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The amino acid sequence of a protein encodes more than the native three-dimensional structure; it encodes the entire energy landscape – an ensemble of conformations whose energetics and dynamics are finely tuned for folding, binding, turnover, and function. Small variations in the sequence and environment modulate this landscape and can have effects that range from undetectable to pathological. I will present our recent results probing how cellular factors such as the ribosome, translation and ubiquitination affect the energetics and dynamics of a protein. 

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Monday 19.10.

8:00 PDT -  11:00 EDT - 15:00 UTC

16:00 UK - 17:00 CET - 18:00 IL

Henry Chapman

Deutsches Elektronen-Synchrotron DESY

A Research Center of the Helmholtz Association

Serial crystallography and diffraction with X-ray FELs

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Using X-ray free-electron laser pulses it is possible to outrun the effects of radiation damage, allowing room temperature measurements of macromolecular crystals at high resolution with a dose thousands of times higher than usually tolerable. Since an X-ray FEL pulse ultimately destroys the sample, measurements are carried out in a serial fashion, one sample at a time.  This has led to the paradigm of serial crystallography, requiring rapid sample delivery, high frame-rate detectors and software to aggregate data into what is essentially a three-dimensional powder diffraction pattern.  High-resolution room-temperature protein structures have been determined from crystals less than 0.01 micron^3 in volume, and high-resolution diffraction can be recorded from 2D macromolecular crystals or single fibrils. The method is especially useful for time-resolved crystallography, radiation-sensitive samples, small crystals, and studies of the dependence of structure on physical conditions and environments. The opportunities for this method have not been fully explored, and all aspects of the method are still under active development.  I will outline some of these opportunities and developments.

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Monday 02.11.

8:00 PDT -  11:00 EDT - 15:00 UTC

16:00 UK - 17:00 CET - 18:00 IL

Ivet Bahar

Department of Computational and Systems Biology, University of Pittsburgh, School of Medicine

Network models in biology: from molecular machinery and evaluation of missense variants, to chromosomal dynamics

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It is widely established that understanding protein dynamics is essential to bridging structure and function. One major challenge in computational modeling of protein dynamics is the computational cost and time required for viewing events of biological significance, the time scale and cooperative nature of which is often beyond the reach of conventional molecular dynamics simulations. Among coarse-grained models that have been developed for addressing this issue, elastic network models (ENMs) found wide usage in molecular biophysics and structural biology. The global motions predicted by ENMs have proven in numerous applications in the last two decades to provide a good description of molecular machinery and allosteric behavior complementing experimental data, despite the simplicity of the model and the lack of specificity. Application to supramolecular structures, including cryo-EM structures, has been a major utility of these models. More recently, ENMs proved useful to exploring chromosomal dynamics, using data from Hi-C experiments to reconstruct in silico the connectivity of the chromatin and provide a physical basis for gene regulation transcription and cell type differentiation. Finally, we will show how machine learning algorithms that incorporate ENM predictions provide an improved assessment of the effect of mutations on function, compared to those based on sequence and structure exclusively, and we discuss future directions.

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William A. Eaton

NIH, NIDDK, Laboratory of Chemical Physics

TBA

Monday 16.11.

8:00 PDT -  11:00 EDT - 15:00 UTC

16:00 UK - 17:00 CET - 18:00 IL

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Amnon Horovitz

Department of Structural Biology, Weizmann Institute of Science

TBA

Monday 30.11.

8:00 PDT -  11:00 EDT - 15:00 UTC

16:00 UK - 17:00 CET - 18:00 IL

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Monday 14.12.

8:00 PDT -  11:00 EDT - 15:00 UTC

16:00 UK - 17:00 CET - 18:00 IL

Steven G. Boxer

Department of Chemistry, Stanford University

Electric Fields and Enzyme Catalysis

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 We have developed the vibrational Stark effect to probe electrostatics and dynamics in organized systems, in particular in proteins where vibrational probes can report on functionally important electric fields. The strategy involves deploying site-specific vibrational probes whose sensitivity to an electric field is measured in a calibrated external electric field.  Once calibrated, these probes, typically nitriles or carbonyls, can be used to probe changes in electric field due to mutations, ligand binding, pH effects, light-induced structural changes, etc.  We can also obtain information on absolute fields by combining vibrational solvatochromism and MD simulations, checked by the vibrational Stark effect calibration.  This frequency-field calibration can be applied to quantify functionally relevantelectric fields at the active site of enzymes.  Using ketosteroid isomerase as a model system, we correlate the field sensed at the bond involved in enzymatic catalysis with the rate of the reaction it catalyzes, including variations in this rate in a series of mutants and variants using non-canonical amino acids. This provides the first direct connection between electric fields and function: for this system electrostatic interactions are a dominant contribution to catalytic proficiency.  Using the vibrational Stark effect, we can now consistently re-interpret results already in the literature and provide a framework for parsing the electrostatic contribution to catalysis in both biological and non-biological systems.  Extensions of this approach to other classes of enzymes, to effects of electrostatics on pathways of photoisomerization in proteins, and to the evolutionary trajectories of enzymes responsible for antibiotic resistance will be described if time permits.

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Michael Woodside

Department of Physics, University of Alberta

TBA

Monday 11.01.

8:00 PDT -  11:00 EDT - 15:00 UTC

16:00 UK - 17:00 CET - 18:00 IL

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YouTube: TBA