Komorowski, Karlo

[["dc.bibliographiccitation.firstpage","557"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Journal of Applied Crystallography"],["dc.bibliographiccitation.lastpage","568"],["dc.bibliographiccitation.volume","54"],["dc.contributor.author","Chappa, Veronica"],["dc.contributor.author","Smirnova, Yuliya G."],["dc.contributor.author","Komorowski, Karlo"],["dc.contributor.author","Müller, Marcus"],["dc.contributor.author","Salditt, Tim"],["dc.date.accessioned","2021-06-01T09:41:58Z"],["dc.date.available","2021-06-01T09:41:58Z"],["dc.date.issued","2021"],["dc.description.abstract","Small unilamellar vesicles (20–100 nm diameter) are model systems for strongly curved lipid membranes, in particular for cell organelles. Routinely, small-angle X-ray scattering (SAXS) is employed to study their size and electron-density profile (EDP). Current SAXS analysis of small unilamellar vesicles (SUVs) often employs a factorization into the structure factor (vesicle shape) and the form factor (lipid bilayer electron-density profile) and invokes additional idealizations: (i) an effective polydispersity distribution of vesicle radii, (ii) a spherical vesicle shape and (iii) an approximate account of membrane asymmetry, a feature particularly relevant for strongly curved membranes. These idealizations do not account for thermal shape fluctuations and also break down for strong salt- or protein-induced deformations, as well as vesicle adhesion and fusion, which complicate the analysis of the lipid bilayer structure. Presented here are simulations of SAXS curves of SUVs with experimentally relevant size, shape and EDPs of the curved bilayer, inferred from coarse-grained simulations and elasticity considerations, to quantify the effects of size polydispersity, thermal fluctuations of the SUV shape and membrane asymmetry. It is observed that the factorization approximation of the scattering intensity holds even for small vesicle radii (∼30 nm). However, the simulations show that, for very small vesicles, a curvature-induced asymmetry arises in the EDP, with sizeable effects on the SAXS curve. It is also demonstrated that thermal fluctuations in shape and the size polydispersity have distinguishable signatures in the SAXS intensity. Polydispersity gives rise to low- q features, whereas thermal fluctuations predominantly affect the scattering at larger q , related to membrane bending rigidity. Finally, it is shown that simulation of fluctuating vesicle ensembles can be used for analysis of experimental SAXS curves."],["dc.identifier.doi","10.1107/S1600576721001461"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/85095"],["dc.identifier.url","https://sfb1286.uni-goettingen.de/literature/publications/115"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-425"],["dc.relation","SFB 1286: Quantitative Synaptologie"],["dc.relation","SFB 1286 | A02: Bestimmung der Struktur synaptischer Organellen durch Röntgenbeugungs- und Bildgebungsverfahren"],["dc.relation.eissn","1600-5767"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Salditt (Structure of Biomolecular Assemblies and X-Ray Physics)"],["dc.rights","CC BY 4.0"],["dc.subject.gro","x-ray scattering"],["dc.subject.gro","membrane biophysics"],["dc.title","The effect of polydispersity, shape fluctuations and curvature on small unilamellar vesicle small-angle X-ray scattering curves"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","4142"],["dc.bibliographiccitation.issue","17"],["dc.bibliographiccitation.journal","Soft Matter"],["dc.bibliographiccitation.lastpage","4154"],["dc.bibliographiccitation.volume","16"],["dc.contributor.author","Komorowski, Karlo"],["dc.contributor.author","Sztucki, Michael"],["dc.contributor.author","Sharpnack, Lewis"],["dc.contributor.author","Brehm, Gerrit"],["dc.contributor.author","Köster, Sarah"],["dc.contributor.author","Salditt, Tim"],["dc.contributor.author","Schaeper, Jannis"],["dc.date.accessioned","2020-04-23T12:28:28Z"],["dc.date.available","2020-04-23T12:28:28Z"],["dc.date.issued","2020"],["dc.description.abstract","We have used time-resolved small-angle X-ray scattering (SAXS) to study the adhesion of lipid vesicles in the electrostatic strong-coupling regime induced by divalent ions. The bilayer structure and the interbilayer distance dw between adhered vesicles was studied for different DOPC:DOPS mixtures varying the surface charge density of the membrane, as well as for different divalent ions, such as Ca2+, Sr2+, and Zn2+. The results are in good agreement with the strong coupling theory predicting the adhesion state and the corresponding like-charge attraction based on ion-correlations. Using SAXS combined with the stopped-flow rapid mixing technique, we find that in highly charged bilayers the adhesion state is only of transient nature, and that the adhering vesicles subsequently transform to a phase of multilamellar vesicles, again with an inter-bilayer distance according to the theory of strong binding. Aside from the stopped-flow SAXS instrumentations used primarily for these results, we also evaluate microfluidic sample environments for vesicle SAXS in view of future extension of this work."],["dc.identifier.doi","10.1039/D0SM00259C"],["dc.identifier.pmid","32319505"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/64290"],["dc.identifier.url","https://mbexc.uni-goettingen.de/literature/publications/186"],["dc.identifier.url","https://sfb1286.uni-goettingen.de/literature/publications/72"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.relation","EXC 2067: Multiscale Bioimaging"],["dc.relation","SFB 1286: Quantitative Synaptologie"],["dc.relation","SFB 1286 | A02: Bestimmung der Struktur synaptischer Organellen durch Röntgenbeugungs- und Bildgebungsverfahren"],["dc.relation","SFB 1286 | B02: Ein in vitro-Verfahren zum Verständnis der struktur-organisierenden Rolle des Vesikel-Clusters"],["dc.relation.eissn","1744-6848"],["dc.relation.issn","1744-683X"],["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.rights","CC BY-NC 3.0"],["dc.subject.gro","x-ray scattering"],["dc.subject.gro","membrane biophysics"],["dc.subject.gro","microfluidics"],["dc.title","Vesicle adhesion in the electrostatic strong-coupling regime studied by time-resolved small-angle X-ray scattering"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1908"],["dc.bibliographiccitation.issue","8"],["dc.bibliographiccitation.journal","Biophysical Journal"],["dc.bibliographiccitation.lastpage","1920"],["dc.bibliographiccitation.volume","114"],["dc.contributor.author","Komorowski, Karlo"],["dc.contributor.author","Salditt, Annalena"],["dc.contributor.author","Xu, Yihui"],["dc.contributor.author","Yavuz, Halenur"],["dc.contributor.author","Brennich, Martha Elisabeth"],["dc.contributor.author","Jahn, Reinhard"],["dc.contributor.author","Salditt, Tim"],["dc.date.accessioned","2020-03-03T08:17:24Z"],["dc.date.available","2020-03-03T08:17:24Z"],["dc.date.issued","2018"],["dc.description.abstract","We have studied the adhesion state (also denoted by docking state) of lipid vesicles as induced by the divalent ions Ca2+ or Mg2+ at well-controlled ion concentration, lipid composition, and charge density. The bilayer structure and the interbilayer distance in the docking state were analyzed by small-angle x-ray scattering. A strong adhesion state was observed for DOPC:DOPS vesicles, indicating like-charge attraction resulting from ion correlations. The observed interbilayer separations of ∼1.6 nm agree quantitatively with the predictions of electrostatics in the strong coupling regime. Although this phenomenon was observed when mixing anionic and zwitterionic (or neutral) lipids, pure anionic membranes (DOPS) with highest charge density σ resulted in a direct phase transition to a multilamellar state, which must be accompanied by rupture and fusion of vesicles. To extend the structural assay toward protein-controlled docking and fusion, we have characterized reconstituted N-ethylmaleimide-sensitive factor attachment protein receptors in controlled proteoliposome suspensions by small-angle x-ray scattering."],["dc.identifier.doi","10.1016/j.bpj.2018.02.040"],["dc.identifier.pmid","29694868"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/63067"],["dc.language.iso","en"],["dc.relation.eissn","1542-0086"],["dc.relation.issn","0006-3495"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Salditt (Structure of Biomolecular Assemblies and X-Ray Physics)"],["dc.rights","CC BY-NC-ND 4.0"],["dc.subject.gro","x-ray scattering"],["dc.subject.gro","membrane biophysics"],["dc.title","Vesicle Adhesion and Fusion Studied by Small-Angle X-Ray Scattering"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]