Köster, Sarah

[["dc.bibliographiccitation.firstpage","8445"],["dc.bibliographiccitation.issue","42"],["dc.bibliographiccitation.journal","Soft Matter"],["dc.bibliographiccitation.lastpage","8454"],["dc.bibliographiccitation.volume","14"],["dc.contributor.author","Saldanha, Oliva"],["dc.contributor.author","Aufderhorst-Roberts, Anders"],["dc.contributor.author","Martinez-Torres, Cristina"],["dc.contributor.author","Kuijs, Merel"],["dc.contributor.author","Koenderink, Gijsje H."],["dc.contributor.author","Köster, Sarah"],["dc.contributor.author","Huber, Klaus"],["dc.contributor.author","Lopez, Carlos G."],["dc.date.accessioned","2020-12-10T18:11:25Z"],["dc.date.available","2020-12-10T18:11:25Z"],["dc.date.issued","2018"],["dc.description.abstract","Intermediate filaments are a major structural element in the cytoskeleton of animal cells that mechanically integrate other cytoskeletal components and absorb externally applied stress. Their role is likely to be linked to their complex molecular architecture which is the product of a multi-step assembly pathway. Intermediate filaments form tetrameric subunits which assemble in the presence of monovalent salts to form unit length filaments that subsequently elongate by end-to-end annealing. The present work characterizes this complex assembly process using reconstituted vimentin intermediate filaments with monovalent salts as an assembly trigger. A multi-scale approach is used, comprising static light scattering, dynamic light scattering and quantitative scanning transmission electron microscopy (STEM) mass measurements. Light scattering reveals the radius of gyration (Rg), molecular weight (Mw) and diffusion coefficient (D) of the assembling filaments as a function of time and salt concentration (cS) for the given protein concentration of 0.07 g L−1. At low cS (10 mM KCl) no lateral or elongational growth is observed, whereas at cS = 50–200 mM, the hydrodynamic cross-sectional radius and the elongation rate increases with cS. Rgversus Mw plots suggest that the mass per unit length increases with increasing salt content, which is confirmed by STEM mass measurements. A kinetic model based on rate equations for a two step process is able to accurately describe the variation of mass, length and diffusion coefficient of the filaments with time and provides a consistent description of the elongation accelerated by increasing cS."],["dc.identifier.doi","10.1039/C8SM01007B"],["dc.identifier.eissn","1744-6848"],["dc.identifier.issn","1744-683X"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/74005"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.relation.eissn","1744-6848"],["dc.relation.issn","1744-683X"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Köster (Cellular Biophysics)"],["dc.subject.gro","cytoskeleton"],["dc.subject.gro","molecular biophysics"],["dc.title","Effect of ionic strength on the structure and elongational kinetics of vimentin filaments"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","11152"],["dc.bibliographiccitation.issue","40"],["dc.bibliographiccitation.journal","Proceedings of the National Academy of Sciences"],["dc.bibliographiccitation.lastpage","11157"],["dc.bibliographiccitation.volume","113"],["dc.contributor.author","Lopez, Carlos G."],["dc.contributor.author","Saldanha, Oliva"],["dc.contributor.author","Huber, Klaus"],["dc.contributor.author","Köster, Sarah"],["dc.date.accessioned","2017-09-07T11:44:34Z"],["dc.date.available","2017-09-07T11:44:34Z"],["dc.date.issued","2016"],["dc.description.abstract","Vimentin intermediate filaments (IFs) are part of a family of proteins that constitute one of the three filament systems in the cytoskeleton, a major contributor to cell mechanics. One property that distinguishes IFs from the other cytoskeletal filament types, actin filaments and microtubules, is their highly hierarchical assembly pathway, where a lateral association step is followed by elongation. Here we present an innovative technique to follow the elongation reaction in solution and in situ by time-resolved static and dynamic light scattering, thereby precisely capturing the relevant time and length scales of seconds to minutes and 60-600 nm, respectively. We apply a quantitative model to our data and succeed in consistently describing the entire set of data, including particle mass, radius of gyration, and hydrodynamic radius during longitudinal association."],["dc.identifier.doi","10.1073/pnas.1606372113"],["dc.identifier.gro","3141606"],["dc.identifier.isi","000384528900047"],["dc.identifier.pmid","27655889"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/457"],["dc.language.iso","en"],["dc.notes.intern","WoS Import 2017-03-10"],["dc.notes.status","final"],["dc.notes.submitter","PUB_WoS_Import"],["dc.relation.issn","0027-8424"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Köster (Cellular Biophysics)"],["dc.subject.gro","cytoskeleton"],["dc.subject.gro","molecular biophysics"],["dc.title","Lateral association and elongation of vimentin intermediate filament proteins: A time-resolved light-scattering study"],["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.artnumber","024108"],["dc.bibliographiccitation.firstpage","1"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Biomicrofluidics"],["dc.bibliographiccitation.lastpage","14"],["dc.bibliographiccitation.volume","10"],["dc.contributor.author","Saldanha, Oliva"],["dc.contributor.author","Brennich, Martha Elisabeth"],["dc.contributor.author","Burghammer, Manfred"],["dc.contributor.author","Herrmann, Harald"],["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","The structural organization of metazoan cells and their shape are established through the coordinated interaction of a composite network consisting of three individual filament systems, collectively termed the cytoskeleton. Specifically, microtubules and actin filaments, which assemble from monomeric globular proteins, provide polar structures that serve motor proteins as tracks. In contrast, intermediate filaments (IFs) assemble from highly charged, extended coiled coils in a hierarchical assembly mechanism of lateral and longitudinal interaction steps into non-polar structures. IF proteins are expressed in a distinctly tissue-specific way and thereby serve to generate the precise plasticity of the respective cells and tissues. Accordingly, in the cell, numerous parameters such as pH and salt concentration are adjusted such that the generation of functional networks is ensured. Here, we transfer the problem for the mesenchymal IF protein vimentin to an in vitro setting and combine small angle x-ray scattering with microfluidics and finite element method simulations. Our approach is adapted to resolve the early assembly steps, which take place in the sub-second to second range. In particular, we reveal the influence of ion species and concentrations on the assembly. By tuning the flow rates and thus concentration profiles, we find a minimal critical salt concentration for the initiation of the assembly. Furthermore, our analysis of the surface sensitive Porod regime in the x-ray data reveals that the formation of first assembly intermediates, so-called unit length filaments, is not a one-step reaction but consists of distinct consecutive lateral association steps followed by radial compaction as well as smoothening of the surface of the full-width filament."],["dc.identifier.doi","10.1063/1.4943916"],["dc.identifier.gro","3141717"],["dc.identifier.isi","000376091900011"],["dc.identifier.pmid","27042250"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/291"],["dc.language.iso","en"],["dc.notes.intern","WoS Import 2017-03-10"],["dc.notes.status","final"],["dc.notes.submitter","PUB_WoS_Import"],["dc.relation.issn","1932-1058"],["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","The filament forming reactions of vimentin tetramers studied in a serial-inlet microflow device by small angle x-ray scattering"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]