A chiral theory of DNA supercoiling

Lead Research Organisation: Imperial College London
Department Name: Dept of Chemistry

Abstract

We propose to bring together three threads of recent progress to develop anew chiral theory of DNA supercoiling. The three threads are i) theelectrostatic theory of interacting helical charge distributions, ii) themechanical theory of elastic braids, and iii) a new efficient approach toderive equilibrium equations for geometric variational problems. The newtheory will for the first time introduce explicitly chiral interactions intothe description of supercoiling, and will uncover the effects driven by theseinteractions. Specifically, we will build a theory to describe foursupercoiling situations: (i) spontaneous formation of free-ended braids,(ii) conformations of braided DNA in single-molecule manipulation experiments,and formation of writhes in (iii) torsionally stressed and (iv) initiallyrelaxed looped DNA, triggered by changing environment.In recent years systematic experimental studies of the torque response ofplectonemically supercoiled and braided DNA have been performed, while moreare anticipated. These require a quantitative theory that better accountsfor the complex DNA-DNA interactions. We will develop that theory. The mainpart of this project is theoretical, but the predictions of the theory willbe tested against new experiments that will be performed in collaborationwith the named Project Partners.

Publications

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Cortini R (2012) Chiral electrostatics breaks the mirror symmetry of DNA supercoiling. in Journal of physics. Condensed matter : an Institute of Physics journal

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Kornyshev AA (2010) From biologically-inspired physics to physics-inspired biology. in Journal of physics. Condensed matter : an Institute of Physics journal

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Lee D (2009) Homology recognition funnel. in The Journal of chemical physics

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Lee D (2013) Chiral effects in dual-DNA braiding in Soft Matter

 
Description 1. The electrostatics problem of two DNA molecules (helical charged rods) in a generalized braided configuration was solved when the pitch of the braid was long compared to the Debye screening length and the tilt angle small, and a mathematical formalism for generalized braids was built to handle later developments based on the mathematical analytical approaches of the UCL partnering team on this grant.

2. A prediction of the spontaneous braiding of helically charged molecules was made, based on a physical theory. Spontaneous braiding of three actin molecules has indeed been observed [T. Ikawa, F. Hoshino, Y. Li, P. Pincus, C. R. Safinya, Phys. Rev. Lett., 98, 018101 (2007)], though not yet for two DNA molecules. Our study suggested that this might only happen under particular ionic conditions, perhaps only for homologous molecules.

3. A model of DNA supercoiling was developed that included helix specific electrostatic forces. Such forces could make the free energy asymmetric with respect to left and right handed supercoiling. When helix specific forces, which favours, as found, left-handed braiding (writhing) were important, the supercoil collapsed into a tightly supercoiled state with left-handed writhing. It was found that with such a transition, due the constraint in the linking number, the DNA twist had to change.

4. A theory was developed for the statistical mechanics of regular symmetric braids formed by molecules interacting through forces that depend on the helical structure. In such braid the average centre lines of the two molecules precess with uniform period about the line axis that is equidistant from the centre lines of each of the two molecule. This theory included undulations of the molecules as well as twisting fluctuations.

5. A model was suggested and developed describing the mechanical braiding of two molecules as in the experiments of G. Charvin, A. Vologodskii, D. Bensimon, V. Croquette, Biophys. J., 88, 4124 (2005). Applying our statistical mechanical theory of braiding to the case when helix specific forces were weak, this model fitted the experimental data well. The data have shown a slight asymmetry, and it was postulated that new type of helix-helix correlation forces could be responsible for this. These correlation forces involved azimuthal orientation of one helix, correlating with the other helix. This model was used to predict the qualitative features of such experiments for such molecules, for instance DNA, where helix specific forces are of electrostatic nature and are strong, and in which the effects of undulations of the molecules have been included.

7. A model to rationalize the chiral effects observed in the braiding experiments of the Wuite group has also been developed. We hope to use to extract information from their experiments about the force between the molecules in their braids, when the experiments got completed.

8. Recent studies of counterion-induced condensation of nucleic acid helices into aggregates in the group of Professor Lois Pollack and the former group of Dr Parsegian at NIH produced several puzzling observations. For instance, trivalent cobalt hexamine ions condensed double-stranded (ds) DNA oligomers but not their more highly charged dsRNA counterparts. Divalent alkaline earth metal ions condensed triple-stranded (ts) DNA oligomers but not dsDNA. We developed a detailed theory which shows that these counterintuitive experimental results can be rationalized within the Kornyshev-Leikin electrostatic zipper model of interactions between molecules with helical charge motifs.
This theory reveals dramatic and nontrivial interplay between the effects of helical structure and thermal rotational fluctuations (which are particularly strong for short oligomers) on electrostatic interaction between oligomeric nucleic acids. Combining predictions for oligomeric and much longer helices, we have also interpret recent experimental studies of the role of counterion charge, structure, and chemistry. These results suggest that an electrostatic zipper attraction might be a major or even dominant force in nucleic acid condensation.

9. The theory of X-ray diffraction from ideal, rigid helices allowed Watson and Crick to unravel the DNA structure, thereby elucidating functions encoded in it. Yet, as we know now, the DNA double helix is neither ideal nor rigid. Its structure varies with the base pair sequence. Its flexibility leads to thermal fluctuations and allows molecules to adapt their structure to optimize their intermolecular interactions. In addition to the double helix symmetry revealed by Watson and Crick, classical X-ray diffraction patterns of DNA contain information about the flexibility, interactions and sequence-related variations encoded within the helical structure. To extract this information, we have developed a new diffraction theory that accounts for these effects. We show how double helix non-ideality and fluctuations broaden the diffraction peaks. Meridional intensity profiles of the peaks at the first three helical layer lines reveal information about structural adaptation and intermolecular interactions. The meridional width of the fifth layer line peaks is inversely proportional to the helical coherence length that characterizes sequence-related and thermal variations in the double helix structure. Analysis of measured fibre diffraction patterns based on this theory yields important parameters that control DNA structure, packing and function. Our analysis of the fine structure of fifth layer line as obtained in the experiments of the group of Z.B. Zimmerman (at NIH) has shown that helical coherence length of DNA is close to 11 nm.

10. Mutual recognition of homologous sequences of DNA before strand exchange is considered to be the most puzzling stage of recombination of genes. In 2001, a mechanism was suggested for a double stranded DNA molecule to recognize from a distance its homologous match in electrolytic solution without unzipping [Kornyshev AA,
Leikin S (2001) Phys Rev Lett 86:3666-3669]. Based on a theory of electrostatic interactions between helical molecules, the difference in the electrostatic interaction energy between homologous duplexes and between nonhomologous duplexes, called the recognition energy, was calculated. Now we have performed a theoretical investigation of the form of the potential well that DNA molecules may feel sliding along each other. This well, the bottom of which is determined by the recognition energy, leads to trapping of the molecular tracks of the same homology in direct juxtaposition. A simple formula for the shape of the well is obtained for torsionally rigid molecule. The well is quasi-exponential. Its half-width is determined by the helical coherence length, introduced first in the same 2001 article, the value of which, as the above mentioned analysis of experimental X-ray diffraction patterns is close to 11 nm. More involved theory was developed for a recognition well (recognition funnel) for torsionally elastic molecules. An ability of torsional adaptation reduces the well. However, based on the estimates that rest on known DNA torsional elastic moduli, the well remains yet substantial for the molecules sliding along each other to stop in 1-1 homology-to-homology juxtaposition. Note that we do not need the funnel to be too deep as the DNA molecules must have a chance for easy departure after the recombination takes place.
Last but not least we have proved that the homology recognition well practically disappears when two homologous DNA molecules scan each other oriented in opposite direction. This is extremely important for experimental tests on the level of single molecule experiments, because the control experiment can be made with the DNA molecules of the same sequences but just oriented in the opposite way. In the recent paper [{Lee DJ(O'), Danilowicz C,Rochester C, Kornyshev AA, Prentiss M. 2016, Lee DJ(O'), Danilowicz C,
Rochester C, Kornyshev AA, Prentiss M. 2016, Evidence of protein-free homology recognition in magnetic bead force-extension experiments.Proc. R. Soc. A 472: 20160186.
http://dx.doi.org/10.1098/rspa.2016.0186] we have demonstrated recognition of homologues withing one long construct DNA molecule, These experiments and their theoretical analysis has shown folding of homologues that makes the end-to-end distance of the molecule shorter and the force distance curves and the magnetic bead force-extension
curves different from the control molecule that does not contain homologous tracts.
Exploitation Route The effects of spontaneous braiding and formation of plectonemes between homologous tracts of DNA will be tested in the laboratory of Dr. Tim Albrecht (Imperial) in his experiments on DNA translocation through nanopores, and in cooperation with the group of Prof. Takeyasu (Kyoto University) in fast AFM and with the group of Dr. Liming Ying (Imperial College) dynamic FRET experiments. A big grant proposal to EPSRC on the subject was filed, but as we have been recently informed it was in the end not funded. We will need to look at other source of funding, possibly together with our US partners at Harvard (Professor Mara Prentiss) and NYU (Kavli Laureate, Professor N.Seeman).

In collaboration with us, Mara Prentiss has already performed crucial single molecule experiments, showing folding of a synthetic DNA with two long identical tracts running within each DNA molecule in opposite directions; using magnetic beads she has also measured the force needed to unfold such molecule and have demonstrated that it is substantially larger than for control molecules that do not contain such tracts and responds to unfolding exactly as a worm-like chain. A joint paper on this subject have been submitted for publication. Very recently, as mentioned in the updated findings above, that group (jointly with us) have experimentally demonstrated folding of homologues within one molecule.

New theory of X-ray diffraction from DNA opens new opportunities to extract further information about the statistical characteristics of DNA structure.

The predictions concerning left handed braiding and chiral effects in the structure of DNA plectonemes are currently navigating four-bead experiments of Professor Gijs Wuite at Free University of Amsterdam.

Altogether, when the homology recognition effects between DNA in protein free solutions, a consequence of the distorted chiral structure of DNA, as predicted initially by Kornyshev and Leikin and developed in this project, will get verified, it will be a big issue. Novel, earlier unknown property encoded into the unique structure of the most important molecule will be experimentally proved. The focus of work will then be to demonstrate how this hidden ability of DNA can manifest itself in interaction and recognition of genes with nucleosomes on them, and later in chromatin. All this is about one of the remaining great puzzles of molecular genetics.
Sectors Chemicals,Education,Healthcare,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology,Other

URL http://rspa.royalsocietypublishing.org/content/472/2191/20160186
 
Description Human Frontiers Science Foundation to Professor Kornyshev for cooperation in DNA biophysicsinlcuding groups from Netherlands, UK and USA.
Amount $254,994 (USD)
Funding ID RGP0049/2010-C304 
Organisation Human Frontier Science Program (HFSP) 
Sector Charity/Non Profit
Country France
Start 06/2010 
End 06/2014
 
Description Collaboration with Dr. Tim Albrecht (Imperial) on different physical methods of experimental investigation of relaxed and supercoiled closed loop DNA. 
Organisation Imperial College London
Department Department of Chemistry
Country United Kingdom 
Sector Academic/University 
PI Contribution We have provided with the theory of the studied effects (the results cannot be disclosed at this stage)
Collaborator Contribution Albrecht's group studied translocation of DNA through nanopores, performed the study of different supercoiled structures by AFM in adsorbed state and by dynamic light scattering (the results cannot be disclosed at this stage).
Impact The experiments has not been finalized due to the lack of funds. The corresponding EPSRC grant proposal has not be awarded, although referee reports were very positive. The work runs on minimal resource. The decisive results will come if we get proper funding. The intermediate results cannot be disclosed at this stage.
Start Year 2010
 
Description Collaboration with Prof. G.Wuite (Free University of Amsterdam) on chiral braiding experiments 
Organisation Free University of Amsterdam
Department Department of Physics
Country Netherlands 
Sector Academic/University 
PI Contribution We have provided a theory of chiral effects in forced DNA supercoiling.
Collaborator Contribution The group of professor Wuite has done some preliminary experiments navigated by our theory.
Impact There are now finally established results but just some preliminary findings: see Friction and Interactions between Bare DNA Molecules: The Role of DNA Handedness. King, GA, Cortini, R; Lee, DJ; Kornyshev, AA; Wuite, GJL, BIOPHYSICAL JOURNAL (2014) " Friction and Interactions between Bare DNA Molecules: The Role of DNA Handedness". Volume: 106 Issue: 2 Pages: 439A-440A Supplement: 1. These dual molecule 4 bead bead experiments are very difficult to perform, and the work is still in progress.
Start Year 2010
 
Description Collaboration with Professor Kenichi Yoshikawa and Yuko Yoshikawa (Doshisha University, Japan) 
Organisation Doshisha University
Country Japan 
Sector Academic/University 
PI Contribution I provided ideas and theory of self organization of DNA (medium size oligomers and long DNA under confinement) - more details cannot be disclosed at this stage.
Collaborator Contribution Kenichi Yoshikawa and Yuko Yoshikawa work on corresponding experiments - more details cannot be disclosed at this stage.
Impact We do not have publishable results yet, but both parties are working on finalizing, correspondingly, theory and experiments.
Start Year 2014
 
Description Collaboration with Professor Kunio Takeyasu (Kyoto University) on fast AFM imaging of supercoild structures 
Organisation University of Kyoto
Department Graduate School of Biostudies
Country Japan 
Sector Academic/University 
PI Contribution We have provided ideas of new experiments and a summary of expected effects (details cannot be disclosed at this stage)
Collaborator Contribution They contribute a performance of experiments using their unique super sensitive high frequency AFM machine and Takeyasu's know how (see his book: https://www.crcpress.com/Atomic-Force-Microscopy-in-Nanobiology/Takeyasu/9789814411585 on this subject) ; more details cannot be disclosed at this stage.
Impact The work is ongoing. An exchange PhD student that will be commissioned by Takeyasu to Imperial (he was just awarded a grant for it). There are yet no results to disclose.
Start Year 2015
 
Description Collaboration with Professor Mara Prentiss (Harvard University) on single molecule DNA experiments 
Organisation Harvard University
Department Department of Physics
Country United States 
Sector Academic/University 
PI Contribution We have provided a theory of here magnetic bead extension force measurements to distinguish a resistance to unfolding of long DNA with homologous tracts and control molecuels not containg such tracts.
Collaborator Contribution They have performed all experiments, provided experimental data and we jointly treated them and wrote a paper, submitted.
Impact The results comprise the third experimental demonstration of existnce of homology recognition at the level of DNA in protein free electrolytic solution. The paper summarizing these findings has been submitted for publication. Before the paper got accepted for publication we will not be reporting the work at conferences or widely publicize it. Disciplines: Biological Physics, Macromolecular science, Physical Chemistry, Molecular genetics
Start Year 2013
 
Description Collaboration with the group of Professor Gert Van der Heijden (UCL)-parner on the grant 
Organisation University College London
Department Department of Civil, Environmental and Geomatic Engineering
Country United Kingdom 
Sector Academic/University 
PI Contribution We have provide a theory of chiral electrostatic interactions between DNA in sulutions including the theory of torsional elasticity and fluctuations.
Collaborator Contribution The UCL group provided original, and advance theory of mechanical properties of plectonemes and performed some simulations.
Impact The biologically important problem of DNA braiding was studied in the past by means of dual-DNA magnetic tweezer experiments. In such experiments, two DNA molecules are braided about each other using an externally imposed force and torque. We developed a theoretical model of molecular braiding that includes interactions between molecules, thermal fluctuations, and the elastic response of molecules, all in a consistent manner. This is useful to study the chiral effects of helix-dependent electrostatic interactions on the braid's equilibrium geometrical and mechanical properties. When helix-dependent forces are weak, our model yields a reasonably accurate reproduction of previously measured extension-rotation curves, where only very slight chirality has been observed. On the other hand, when helix-specific electrostatic forces are strong, the model predicts several new features of the extension-rotation curves. These are: (a) a distinct asymmetry between left-handed and right-handed DNA braiding; (b) the emergence, under a critical pulling force, of coexistence regions of tightly and loosely wound DNA; (c) spontaneous formation of left-handed DNA braids at zero external torque (zero bead rotations). Strong chiral forces are expected for braiding experiments conducted in solutions in which there are counter-ions that bind specifically in the DNA grooves. These results are currently being under experimental investigation by the group of G.Wuite at free University of Amsterdam.
Start Year 2009
 
Description National Institute of Child Health 
Organisation National Institute of Child Health (NICH)
Country Pakistan 
Sector Hospitals 
PI Contribution Our contribution was in formulation of the models, their mathematical solutions, and participation in analysis of experimental data.
Collaborator Contribution Our partner from NIH, Head of the Section of Physical Biochemistry, Dr. S. Leikin, provided a broad knowledge of DNA related phenomena; he was instrumental in the choice of the problems to handle, participated in the formulation of the models and their solutions, his participation in analysis of experimental data was crucial.
Impact A number of fundamental problems in DNA biophysics have been solved, as documented in a series of publications quoted in the publication section of the Outcomes. The subject was interdisciplinary, at the interface of biophysics, soft matter physics, physical chemistry and electrochemistry.
 
Description "8th Liquid Matter Conference" conference, September 2011, Vienna, Austria 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact This was a poster presentation on the results of the project of the PhD student Ruggero Cortini. Participation in it was very youthful for his growth as a young researcher.
Year(s) Of Engagement Activity 2011
URL http://lmc2011.univie.ac.at/general-information/
 
Description A series of RSC Interdisciplinary Prize Lectures 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact 1. University of Southampton, 2. University of Nottingham, 3. UCL (symposium of RSC Awardies), 4. University of Edinbourgh (video translated to St.Andrews). All lectures were on the subject of the DNA biophysics work that highlighted the findings of the project.
Year(s) Of Engagement Activity 2011
URL http://www.rsc.org/events/detail/5488/physical-chemistry-awards-symposium
 
Description An affiliated invited lecture (Prof.Kornyshev) at International Conferences on Advanced Materials, Malta, (Valetta, Malta, 16-20 July, 2010) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact That was a special evening 1 hour after dinner University of Malta guest lecture "Physics of DNA: Unravelling Hidden Abilities of the Most Important Molecule", addressed to participant to all the conferences and academics of the University of Malta and students. The talk presented the most excited finding of our ongoing work and an overview of the whole area.
Year(s) Of Engagement Activity 2010
URL http://home.um.edu.mt/auxetic/auxetics2010/programme.pdf
 
Description CECAM Workshop on "DNA-based self-assembly: theory, simulations and experiments", December 2013, Vienna 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact This was an invited talk presented by PhD student Ruggero Cortini. The talk sparked questions and helped to disseminate the results of the project
Year(s) Of Engagement Activity 2013,2015
URL http://www.cecam.org/workshop-878.html
 
Description DNA World Congress "DNA Days", Dalian, April 20011, Invited talk 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Invitede talk of Prof. A. Kornyshev on "Physics of DNA: Unravelling hidden abilities of the most important molecule" delivered to a large audience of Chinese academics and participants from Asia and the speakers from the rest of the world.
Year(s) Of Engagement Activity 2011
URL http://www.dnaday.com/2011/
 
Description Frontiers in Statistical Mechanics and Complex Systems (June 2012, University of Catania, Italy) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact This was an invited talk, personally to a PhD student Ruggero Cortini and delivered by him, in which he reported the results of the project. The talked sparked questions and helped to disseminate the results of the project.
Year(s) Of Engagement Activity 2012
URL http://www.agenda.unict.it/allegati/articolo/189.pdf
 
Description Invited Keynote lecture at a London Symposium Sensors in Medicine (London, March 2013) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Prof. A.Kornyshev delivered a keynote lectture "Similia -similibus, or how homologous genes sense each other from a distance".
The talk caused a lot of questions and was very well received by this new, in the context of this project, sensor community.
Year(s) Of Engagement Activity 2013
URL http://www.sensor100.com/sensmed2013/conference.html
 
Description Invited keynote lecture of Professor Kornyshev at Biostudies & iCeMS Joint Symposium, 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Professor Kornyshev delivered a talk at Biostudies & iCeMS Joint Symposium, "Hierarchical Dynamics of Nucleic Acid: Synergy between Structure and Function", September 2014, Kyoto University- Kyoto, Japan on the subject of DNA-DNA interaction and recognition.
The talked triggered started collaboration with the group of Professor K. Takeyasu at Kyoto University.
Year(s) Of Engagement Activity 2014
URL http://www.icems.kyoto-u.ac.jp/common/doc/rsch/smnr/140922_HDNA_symp_program.pdf
 
Description Invited seminar talk by Prof. A. Kornyshev at Molecular Biology Colloquium at Waseda University on DNA biophysics (September 2014) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Professional Practitioners
Results and Impact This was a talk in one of the world leading groups in experimental studies of nuclear acids (Prof. T. Ohyama). We plan some joint projects that have not been started yet.
Year(s) Of Engagement Activity 2014
 
Description Invited talk by Prof. A. Kornyshev at International Workshop on Protein-DNA Interactions: from Biophysics to Cancer Biology (December 7-8, 2017 Houston, Texas) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Study participants or study members
Results and Impact The activity gathered a multidisciplinary audience of physicists, chemists, and biologists, and summarizing the achievements of research based on and followed after this EPSRC grant helped to establish new scientific contact and collaborations.
Year(s) Of Engagement Activity 2017
URL https://bmb.utmb.edu/PDI/speakers.asp
 
Description Invited talk of A.Kornyshev at CECAM Workshop on "DNA-based self-assembly: theory, simulations and experiments", December 2013, Vienna 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact This was invited talk focused on our findings on homology recognitition delivered by the PI of the project, Prof. A.Kornyshev.
The talk sparked questions and discussion.
Year(s) Of Engagement Activity 2013
URL http://www.cecam.org/workshop-878.html
 
Description Invited talk of Professor A. Kornyshev at Japanese Physical Society, September 2014 (Biophysics section) , Nagoya, Japan 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact The talk has put on the screen my arrival in Japan as an Awardee of JSPS.
Year(s) Of Engagement Activity 2014
 
Description Invited talk of Ruggero Cortini at an International Workshop "Topological Aspects of DNA Function and Protein Folding", September 2012, Newton Institute, 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The talk of Ruggero Cortini at the workshop hosted by the Newton Institute in Cambridge, UK, disseminated the results of the project to the community of leading experts in theoretical biophysics and mathematical biology.
Year(s) Of Engagement Activity 2012
URL https://www.newton.ac.uk/event/todw02
 
Description Invitred talk of Ruggero Cortini at 4ème réunion du GdR ADN, April 2015 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact This was an invited presentation at a meeting on Structure and dynamics of cell nuclei, hosted by University of Pierre and Marie Curie, with mainly French participants. The talk was on Cortini's follow up research activities after he finished his work on the project. That help to establish his reputation in France as an aspiring young researcher and in an indirect way influenced receiving his next fellowship.
Year(s) Of Engagement Activity 2015
URL https://indico.in2p3.fr/event/11378/
 
Description MathBio Workshop, Transport in a cell (12-15 April, 2010, Columbus, Ohio, USA) Invited talk of Professor A. Kornyshev 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact I delivered the tall on "DNA chasing DNA: physics of homology recognition and the secret of perfect match" which conveyed the basic ideas and results of the DNA biophysics studies in my group, starting from Kornyshev-Leikin theory to its later developments. The talks triggered discussions and useful information exchange with the conference organizer, Prof. A. Kolomeisky.
Year(s) Of Engagement Activity 2016
URL https://mbi.osu.edu/event/?id=118
 
Description Soft Matter and Biological Physics Seminar, Cavendish Laboratory, Cambridge University, 4 December (2009) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Professional Practitioners
Results and Impact I gave an overview of our DNA biophysics work including the started project related studies.
Year(s) Of Engagement Activity 2009