Hémonnot, Clément Y. J.

[["dc.bibliographiccitation.firstpage","336"],["dc.bibliographiccitation.issue","S2"],["dc.bibliographiccitation.journal","Microscopy and Microanalysis"],["dc.bibliographiccitation.lastpage","339"],["dc.bibliographiccitation.volume","24"],["dc.contributor.author","Wittmeier, Andrew"],["dc.contributor.author","Cassini, Chiara"],["dc.contributor.author","Hémonnot, Clément Y. J."],["dc.contributor.author","Weinhausen, Britta"],["dc.contributor.author","Bernhardt, Marten"],["dc.contributor.author","Salditt, Tim"],["dc.contributor.author","Köster, Sarah"],["dc.date.accessioned","2020-04-23T14:35:13Z"],["dc.date.available","2020-04-23T14:35:13Z"],["dc.date.issued","2018"],["dc.identifier.doi","10.1017/S1431927618013983"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/64328"],["dc.language.iso","en"],["dc.relation.eissn","1435-8115"],["dc.relation.issn","1431-9276"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Köster (Cellular Biophysics)"],["dc.relation.workinggroup","RG Salditt (Structure of Biomolecular Assemblies and X-Ray Physics)"],["dc.subject.gro","x-ray imaging"],["dc.subject.gro","x-ray scattering"],["dc.subject.gro","cellular biophysics"],["dc.title","Scanning Small-Angle-X-Ray Scattering for Imaging Biological Cells"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","705"],["dc.bibliographiccitation.issue","6"],["dc.bibliographiccitation.journal","Acta crystallographica. Section D, Structural biology"],["dc.bibliographiccitation.lastpage","717"],["dc.bibliographiccitation.volume","72"],["dc.contributor.author","Tauchert, Marcel J."],["dc.contributor.author","Hémonnot, Clément"],["dc.contributor.author","Neumann, Piotr"],["dc.contributor.author","Köster, Sarah"],["dc.contributor.author","Ficner, Ralf"],["dc.contributor.author","Dickmanns, Achim"],["dc.date.accessioned","2020-12-10T18:26:04Z"],["dc.date.available","2020-12-10T18:26:04Z"],["dc.date.issued","2016"],["dc.description.abstract","In eukaryotic cells, the exchange of macromolecules between the nucleus and cytoplasm is highly selective and requires specialized soluble transport factors. Many of them belong to the importin-beta superfamily, the members of which share an overall superhelical structure owing to the tandem arrangement of a specific motif, the HEAT repeat. This structural organization leads to great intrinsic flexibility, which in turn is a prerequisite for the interaction with a variety of proteins and for its transport function. During the passage from the aqueous cytosol into the nucleus, the receptor passes the gated channel of the nuclear pore complex filled with a protein meshwork of unknown organization, which seems to be highly selective owing to the presence of FG-repeats, which are peptides with hydrophobic patches. Here, the structural changes of free importin-beta from a single organism, crystallized in polar (salt) or apolar (PEG) buffer conditions, are reported. This allowed analysis of the structural changes, which are attributable to the surrounding milieu and are not affected by bound interaction partners. The importin-beta structures obtained exhibit significant conformational changes and suggest an influence of the polarity of the environment, resulting in an extended conformation in the PEG condition. The significance of this observation is supported by SAXS experiments and the analysis of other crystal structures of importin-beta deposited in the Protein Data Bank."],["dc.identifier.doi","10.1107/S2059798316004940"],["dc.identifier.fs","622294"],["dc.identifier.gro","3141673"],["dc.identifier.isi","000379911500002"],["dc.identifier.issn","2059-7983"],["dc.identifier.pmid","27303791"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/75940"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.notes.status","final"],["dc.notes.submitter","PUB_WoS_Import"],["dc.relation.issn","2059-7983"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Köster (Cellular Biophysics)"],["dc.subject.gro","x-ray scattering"],["dc.subject.gro","molecular biophysics"],["dc.title","Impact of the crystallization condition on importin-β conformation"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","3313"],["dc.bibliographiccitation.issue","10"],["dc.bibliographiccitation.journal","Biomacromolecules"],["dc.bibliographiccitation.lastpage","3321"],["dc.bibliographiccitation.volume","16"],["dc.contributor.author","Hémonnot, Clément Y. J."],["dc.contributor.author","Mauermann, Monika"],["dc.contributor.author","Herrmann, Harald"],["dc.contributor.author","Köster, Sarah"],["dc.date.accessioned","2017-09-07T11:43:30Z"],["dc.date.available","2017-09-07T11:43:30Z"],["dc.date.issued","2015"],["dc.description.abstract","The intermediate filament proteins keratin K8 and K18 constitute an essential part of the cytoskeleton in simple epithelial cell layers, structurally enforcing their mechanical resistance. K8/K18 heterodimers form extended filaments and higher-order structures including bundles and networks that bind to cell junctions. We study the assembly of these proteins in the presence of monovalent or divalent ions by small-angle X-ray scattering. We find that both ion species cause an increase of the filament diameter when their concentration is increased; albeit, much higher values are needed for the monovalent compared to the divalent ions for the same effect. Bundling occurs also for monovalent ions and at comparatively low concentrations of divalent ions, very different from vimentin intermediate filaments, a fibroblast-specific cytoskeleton component. We explain these differences by variations in charge and hydrophobicity patterns of the proteins. These differences may reflect the respective physiological situation in stationary cell layers versus single migrating fibroblasts."],["dc.identifier.doi","10.1021/acs.biomac.5b00965"],["dc.identifier.gro","3141817"],["dc.identifier.isi","000362863500025"],["dc.identifier.pmid","26327161"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/1401"],["dc.language.iso","en"],["dc.notes.intern","WoS Import 2017-03-10"],["dc.notes.status","final"],["dc.notes.submitter","PUB_WoS_Import"],["dc.relation.eissn","1526-4602"],["dc.relation.issn","1525-7797"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Köster (Cellular Biophysics)"],["dc.subject.gro","x-ray scattering"],["dc.subject.gro","cytoskeleton"],["dc.subject.gro","molecular biophysics"],["dc.title","Assembly of Simple Epithelial Keratin Filaments: Deciphering the Ion Dependence in Filament Organization"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1220"],["dc.bibliographiccitation.issue","10"],["dc.bibliographiccitation.journal","ChemPhysChem"],["dc.bibliographiccitation.lastpage","1223"],["dc.bibliographiccitation.volume","18"],["dc.contributor.author","Saldanha, Oliva"],["dc.contributor.author","Graceffa, Rita"],["dc.contributor.author","Hémonnot, Clément Y. J."],["dc.contributor.author","Ranke, Christiane"],["dc.contributor.author","Brehm, Gerrit"],["dc.contributor.author","Liebi, Marianne"],["dc.contributor.author","Marmiroli, Benedetta"],["dc.contributor.author","Weihausen, Britta"],["dc.contributor.author","Burghammer, Manfred"],["dc.contributor.author","Köster, Sarah"],["dc.date.accessioned","2018-02-12T12:27:30Z"],["dc.date.available","2018-02-12T12:27:30Z"],["dc.date.issued","2017"],["dc.description.abstract","Encapsulating reacting biological or chemical samples in microfluidic droplets has the great advantage over single‐phase flows of providing separate reaction compartments. These compartments can be filled in a combinatoric way and prevent the sample from adsorbing to the channel walls. In recent years, small‐angle X‐ray scattering (SAXS) in combination with microfluidics has evolved as a nanoscale method of such systems. Here, we approach two major challenges associated with combining droplet microfluidics and SAXS. First, we present a simple, versatile, and reliable device, which is both suitable for stable droplet formation and compatible with in situ X‐ray measurements. Second, we solve the problem of “diluting” the sample signal by the signal from the oil separating the emulsion droplets by multiple fast acquisitions per droplet and data thresholding. We show that using our method, even the weakly scattering protein vimentin provides high signal‐to‐noise ratio data."],["dc.identifier.doi","10.1002/cphc.201700221"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/12175"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Köster (Cellular Biophysics)"],["dc.subject.gro","x-ray scattering"],["dc.subject.gro","cytoskeleton"],["dc.subject.gro","molecular biophysics"],["dc.subject.gro","microfluidics"],["dc.title","Rapid Acquisition of X-Ray Scattering Data from Droplet-Encapsulated Protein Systems"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","3553"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","ACS Nano"],["dc.bibliographiccitation.lastpage","3561"],["dc.bibliographiccitation.volume","10"],["dc.contributor.author","Hemonnot, Clement Y. J."],["dc.contributor.author","Reinhardt, Juliane"],["dc.contributor.author","Saldanha, Oliva"],["dc.contributor.author","Patommel, Jens"],["dc.contributor.author","Graceffa, Rita"],["dc.contributor.author","Weinhausen, Britta"],["dc.contributor.author","Burghammer, Manfred"],["dc.contributor.author","Schroer, Christian G."],["dc.contributor.author","Köster, Sarah"],["dc.date.accessioned","2017-09-07T11:54:36Z"],["dc.date.available","2017-09-07T11:54:36Z"],["dc.date.issued","2016"],["dc.description.abstract","In recent years, X-ray imaging of biological cells has emerged as a complementary alternative to fluorescence and electron microscopy. Different techniques were established and successfully applied to macromolecular assemblies and structures in cells. However, while the resolution is reaching the nanometer scale, the dose is increasing. It is essential to develop strategies to overcome or reduce radiation damage. Here we approach this intrinsic problem by combing two different X-ray techniques, namely ptychography and nanodiffraction, in one experiment and on the same sample. We acquire low dose ptychography overview images of whole cells at a resolution of 65 nm. We subsequently record high-resolution nanodiffraction data from regions of interest. By comparing images from the two modalities, we can exclude strong effects of radiation damage on the specimen. From the diffraction data we retrieve quantitative structural information from intracellular bundles of keratin intermediate filaments such as a filament radius of 5 nm, hexagonal geometric arrangement with an interfilament distance of 14 nm and bundle diameters on the order of 70 nm. Thus, we present an appealing combined approach to answer a broad range of questions in soft matter physics, biophysics and biology."],["dc.identifier.doi","10.1021/acsnano.5b07871"],["dc.identifier.gro","3141720"],["dc.identifier.isi","000372855400058"],["dc.identifier.pmid","26905642"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/324"],["dc.language.iso","en"],["dc.notes.intern","WoS Import 2017-03-10"],["dc.notes.status","final"],["dc.notes.submitter","PUB_WoS_Import"],["dc.relation.eissn","1936-086X"],["dc.relation.issn","1936-0851"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Köster (Cellular Biophysics)"],["dc.subject.gro","x-ray imaging"],["dc.subject.gro","x-ray scattering"],["dc.subject.gro","cytoskeleton"],["dc.subject.gro","cellular biophysics"],["dc.title","X-rays Reveal the Internal Structure of Keratin Bundles in Whole Cells"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","10661"],["dc.bibliographiccitation.issue","12"],["dc.bibliographiccitation.journal","ACS Nano"],["dc.bibliographiccitation.lastpage","10670"],["dc.bibliographiccitation.volume","10"],["dc.contributor.author","Hémonnot, Clément Y. J."],["dc.contributor.author","Ranke, Christiane"],["dc.contributor.author","Saldanha, Oliva"],["dc.contributor.author","Graceffa, Rita"],["dc.contributor.author","Hagemann, Johannes"],["dc.contributor.author","Köster, Sarah"],["dc.date.accessioned","2017-11-28T10:03:27Z"],["dc.date.available","2017-11-28T10:03:27Z"],["dc.date.issued","2016"],["dc.description.abstract","X-ray imaging of intact biological cells is emerging as a complementary method to visible light or electron microscopy. Owing to the high penetration depth and small wavelength of X-rays, it is possible to resolve subcellular structures at a resolution of a few nanometers. Here, we apply scanning X-ray nanodiffraction in combination with time-lapse bright-field microscopy to nuclei of 3T3 fibroblasts and thus relate the observed structures to specific phases in the cell division cycle. We scan the sample at a step size of 250 nm and analyze the individual diffraction patterns according to a generalized Porod’s law. Thus, we obtain information on the aggregation state of the nuclear DNA at a real space resolution on the order of the step size and in parallel structural information on the order of few nanometers. We are able to distinguish nucleoli, heterochromatin, and euchromatin in the nuclei and follow the compaction and decompaction during the cell division cycle."],["dc.identifier.doi","10.1021/acsnano.6b05034"],["dc.identifier.fs","623722"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/10593"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.relation.eissn","1936-086X"],["dc.relation.issn","1936-0851"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Köster (Cellular Biophysics)"],["dc.subject","biological cells; cell division cycle; DNA compaction; nanostructure; X-ray nanodiffraction"],["dc.subject.gro","x-ray imaging"],["dc.subject.gro","x-ray scattering"],["dc.subject.gro","cellular biophysics"],["dc.title","Following DNA Compaction During the Cell Cycle by X-ray Nanodiffraction"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","unknown"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","171"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Lab on a Chip"],["dc.bibliographiccitation.lastpage","178"],["dc.bibliographiccitation.volume","18"],["dc.contributor.author","Denz, Manuela"],["dc.contributor.author","Brehm, Gerrit"],["dc.contributor.author","Hémonnot, Clément Y. J."],["dc.contributor.author","Spears, Heidi"],["dc.contributor.author","Wittmeier, Andrew"],["dc.contributor.author","Cassini, Chiara"],["dc.contributor.author","Saldanha, Oliva"],["dc.contributor.author","Perego, Eleonora"],["dc.contributor.author","Diaz, Ana"],["dc.contributor.author","Köster, Sarah"],["dc.contributor.author","Burghammer, Manfred"],["dc.date.accessioned","2021-06-01T10:50:48Z"],["dc.date.available","2021-06-01T10:50:48Z"],["dc.date.issued","2018"],["dc.description.abstract","The combination of microfluidics and X-ray methods attracts a lot of attention from researchers as it brings together the high controllability of microfluidic sample environments and the small length scales probed by X-rays. In particular, the fields of biophysics and biology have benefited enormously from such approaches. We introduce a straightforward fabrication method for X-ray compatible microfluidic devices made solely from cyclic olefin copolymers. We benchmark the performance of the devices against other devices including more commonly used Kapton windows and obtain data of equal quality using small angle X-ray scattering. An advantage of the devices presented here is that no gluing between interfaces is necessary, rendering the production very reliable. As a biophysical application, we investigate the early time points of the assembly of vimentin intermediate filament proteins into higher-order structures. This weakly scattering protein system leads to high quality data in the new devices, thus opening up the way for numerous future applications."],["dc.identifier.doi","10.1039/C7LC00824D"],["dc.identifier.eissn","1473-0189"],["dc.identifier.issn","1473-0197"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/86792"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-425"],["dc.notes.status","zu prüfen"],["dc.relation.eissn","1473-0189"],["dc.relation.issn","1473-0197"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Köster (Cellular Biophysics)"],["dc.subject.gro","x-ray scattering"],["dc.subject.gro","microfluidics"],["dc.title","Cyclic olefin copolymer as an X-ray compatible material for microfluidic devices"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","8542"],["dc.bibliographiccitation.issue","9"],["dc.bibliographiccitation.journal","ACS Nano"],["dc.bibliographiccitation.lastpage","8559"],["dc.bibliographiccitation.volume","11"],["dc.contributor.author","Hémonnot, Clément Y. J."],["dc.contributor.author","Köster, Sarah"],["dc.date.accessioned","2018-02-12T12:29:16Z"],["dc.date.available","2018-02-12T12:29:16Z"],["dc.date.issued","2017"],["dc.description.abstract","Cells and biological materials are large objects in comparison to the size of internal components such as organelles and proteins. An understanding of the functions of these nanoscale elements is key to elucidating cellular function. In this review, we describe the advances in X-ray scattering and diffraction techniques for imaging biological systems at the nanoscale. We present a number of principal technological advances in X-ray optics and development of sample environments. We identify radiation damage as one of the most severe challenges in the field, thus rendering the dose an important parameter when putting different X-ray methods in perspective. Furthermore, we describe different successful approaches, including scanning and full-field techniques, along with prominent examples. Finally, we present a few recent studies that combined several techniques in one experiment in order to collect highly complementary data for a multidimensional sample characterization."],["dc.identifier.doi","10.1021/acsnano.7b03447"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/12176"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Köster (Cellular Biophysics)"],["dc.subject.gro","x-ray imaging"],["dc.subject.gro","x-ray scattering"],["dc.subject.gro","cellular biophysics"],["dc.title","Imaging of Biological Materials and Cells by X-ray Scattering and Diffraction"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.seriesnr","20"],["dc.contributor.author","Hémonnot, Clément"],["dc.date.accessioned","2018-05-03T10:44:56Z"],["dc.date.available","2018-05-03T10:44:56Z"],["dc.date.issued","2016"],["dc.description.abstract","The advances and technical improvements of X-ray imaging techniques, taking advantage of X-ray focussing optics and high intensity synchrotron sources, nowadays allow for the use of X-rays to probe the cellular nanoscale. Importantly, X-rays permit thick samples to be imaged without sectioning or slicing. In this work, two macromolecules, namely keratin intermediate filament (IF) proteins and DNA, both essential components of cells, were studied by X-ray techniques. Keratin IF proteins make up an integral part of the cytoskeleton of epithelial cells and form a dense intracellular network of bundles. This network is built from monomers in a hierarchical fashion. Thus, the keratin structure formation spans a large range of length scales from a few nanometres (monomers) to micrometres (networks). Here, keratin was studied at three different scales: i) filaments, ii) bundles and iii) networks. Solution small-angle X-ray scattering revealed distinct structural and organisational characteristics of these highly charged polyelectrolyte filaments, such as increasing radius with increasing salt concentration and spatial accumulation of ions depending on the salt concentration. The results are quantified by employing advanced modelling of keratin IFs by a core cylinder fl anked with Gaussian chains. Scanning micro- diffraction was used to study keratin at the bundle scale. Very different morphologies of keratin bundles were observed at different salt conditions. At the network scale, new imaging approaches and analyses were applied to the study of whole cells. Ptychography and scanning X-ray nano-diffraction imaging were performed on the same cells, allowing for high resolution in real and reciprocal space, thereby revealing the internal structure of these networks. By using a fitting routine based on simulations of IFs packed on a hexagonal lattice, the radius of each fi lament and distance between fi laments were retrieved. In mammalian cells, each nucleus contains 2 nm-thick DNA double helices with a total length of about 2 m. The DNA strands are packed in a highly hierarchical manner into individual chromosomes. DNA was studied in intact cells by visible light microscopy and scanning X-ray nano-diffraction, unveiling the compaction und decompaction of DNA during the cell cycle. Thus, we obtained information on the aggregation state of the nuclear DNA at a real space resolution on the order of few hundreds nm. To exploit to the reciprocal space information, individual diffraction patterns were analysed according to a generalised Porod’s law at a resolution down to 10 nm. We were able to distinguish nucleoli, heterochromatin and euchromatin in the nuclei and follow the compaction and decompaction during the cell division cycle."],["dc.format.extent","176"],["dc.identifier.doi","10.17875/gup2016-996"],["dc.identifier.isbn","978-3-86395-287-7"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?univerlag-isbn-978-3-86395-287-7"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/14487"],["dc.identifier.urn","urn:nbn:de:gbv:7-isbn-978-3-86395-287-7-4"],["dc.notes.intern","TASK GROB-550"],["dc.notes.status","zu prüfen"],["dc.publisher","Universitätsverlag Göttingen"],["dc.publisher.place","Göttingen"],["dc.relation.crisseries","Göttingen Series in X-Ray Physics"],["dc.relation.ispartofseries","Göttingen Series in X-ray Physics; 20"],["dc.rights","CC BY-SA 4.0"],["dc.rights.uri","http://creativecommons.org/licenses/by-sa/4.0/"],["dc.title","Investigating Cellular Nanoscale with X-rays"],["dc.title.subtitle","From Proteins to Networks"],["dc.type","thesis"],["dc.type.internalPublication","unknown"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]