Mineralized scale patterns on the cell periphery of the chrysophyte Mallomonas determined by comparative 3D Cryo-FIB SEM data processing
In this study, the scale case of the photosynthetic synurophyte Mallomonas was preserved in aqueous suspension using high-pressure freezing (HPF). From this specimen, a three-dimensional (3D) data set spanning a volume of about 25.6μm × 19.2μm × 4.2μm with a voxel size of 12.5nm × 12.5nm × 25.0nm was collected by Cryo-FIB SEM in 3 hours and 24 minutes. SEM imaging using In-lens SE detection allowed to clearly differentiate between mineralized, curved scales of less than 0.2μm thickness and organic cellular ultrastructure or vitrified ice. The three-dimensional spatial orientations and shapes of a minimum set of sca...
Source: Journal of Structural Biology - October 14, 2019 Category: Biology Source Type: research
Lateral A11 type tetramerization in lamins
Publication date: Available online 11 October 2019Source: Journal of Structural BiologyAuthor(s): Anastasia V. Lilina, Anastasia A. Chernyatina, Dmytro Guzenko, Sergei V. StrelkovAbstractThe assembly of intermediate filaments (IFs) including nuclear lamins is driven by specific interactions of the elementary coiled-coil dimers in both lateral and longitudinal direction. The assembly mode A11 is dependent on lateral tetramerization of the second coiled-coil segment (coil1b) in antiparallel fashion. Recent cryo-electron microscopy studies pointed to 3.5 nm lamin filaments built from two antiparallel threads of longitudinally...
Source: Journal of Structural Biology - October 13, 2019 Category: Biology Source Type: research
A microtubule RELION-based pipeline for cryo-EM image processing
Publication date: Available online 11 October 2019Source: Journal of Structural BiologyAuthor(s): Alexander D. Cook, Szymon W. Manka, Su Wang, Carolyn A. Moores, Joseph AthertonAbstractMicrotubules are polar filaments built from αβ-tubulin heterodimers that exhibit a range of architectures in vitro and in vivo. Tubulin heterodimers are arranged helically in the microtubule wall but many physiologically relevant architectures exhibit a break in helical symmetry known as the seam. Noisy 2D cryo-electron microscopy projection images of pseudo-helical microtubules therefore depict distinct but highly similar views owing to t...
Source: Journal of Structural Biology - October 11, 2019 Category: Biology Source Type: research
High-resolution structures of annexin A5 in a two-dimensional array
This study provides molecular insight into how annexins modulate the physical properties of cell membranes as a function of Ca2+ concentration and the phospholipid composition of the membrane. (Source: Journal of Structural Biology)
Source: Journal of Structural Biology - October 10, 2019 Category: Biology Source Type: research
Modeling membrane proteins: the importance of cysteine amino-acids
Publication date: Available online 5 October 2019Source: Journal of Structural BiologyAuthor(s): Evgeni Grazhdankin, Michal Stepniewski, Henri XhaardAbstractComputational modeling of membrane proteins is critical to understand biochemical systems and to support chemical biology. In this work, we use a dataset of 448 non-redundant membrane protein chains to expose a “rule” that governs membrane protein structure: free cysteine thiols are not found accessible to oxidative compartments such as the extracellular space, but are rather involved in disulphide bridges. Taking as examples the 1018 three-dimensional models produ...
Source: Journal of Structural Biology - October 7, 2019 Category: Biology Source Type: research
