Biology subjects

van Dorst, S.

Publications and source records attributed to van Dorst, S..

6 recordsLinked to original sources

bioRxiv2026

Far-Red Light Photoacclimation Rewires Antenna-Photosystem Organization in Cyanobacterial Cells

Thylakoid membrane remodeling regulates photosynthetic activity in response to changing light, but it is unknown whether such membrane-scale control exists in cyanobacteria, which lack the spatially segregated membrane domains of green algae and plants. Using cryo-electron tomography guided by single-cell hyperspectral correlative imaging, we link spectral acclimation state to thylakoid architecture in far-red light adapting cyanobacteria. We determine the native structures of phycobilisome-photosystem II supercomplexes at subnanometer resolution and show that light-dependent molecular changes propagate across scales to restructure the photosynthetic machinery throughout the thylakoids. We further reveal persistent membrane heterogeneity after prolonged far-red light acclimation and identify a low abundance phycobilisome-photosystem I supercomplex in far-red light conditions. Together, our results frame cyanobacterial thylakoids as plastic membranes that remodel antenna-photosystem structure and organization to regulate photosynthesis.

molecular biology↗

bioRxiv2026

Molecular architecture of colossal surface layers from hyperthermophilic archaea

Surface layers (S-layers) are paracrystalline protein lattices that form the outermost layer of the cell envelope in most archaea, providing structural support, protecting against external insults, and co-ordinating interactions with their environment. Despite their widespread occurrence, the molecular and structural details of S-layer architecture in hyperthermophilic archaea remain largely unknown. Here, we report the structure and cellular architecture of the S-layer from the hyperthermophilic archaeon Pyrobaculum arsenaticum by combining in situ electron cryotomography with single-particle electron cryomicroscopy, AlphaFold modelling, and peptide-fingerprinting mass spectrometry. We show that the S-layer is formed by an uncharacterised 292-kDa S-layer protein (SLP) extending 37 nm from the cytoplasmic membrane, making it, to our knowledge, the largest SLP structurally characterised to date. This SLP has a remarkable multidomain architecture comprising 19 immunoglobulin-like domains, 14 canonical and five non-canonical, organised into a lattice-forming core, a stalk, and a unique crown domain that stabilise the S-layer. Comparative genomic analyses unearthed homologous colossal SLP candidates across Thermoproteota, indicating that this distinctive architecture is conserved across diverse archaeal lineages. Together, our findings provide a structural framework for understanding the cell-surface organisation in hyperthermophilic archaea and suggest that these colossal S-layers represent a specialised adaptation to life at high temperatures.

microbiology↗

bioRxiv2026

Conservation and evolution of the ribosome across the photosynthetic lineage

Regulated biogenesis of photosynthetic proteins by the chloroplast ribosomes is central to plant development and environmental adaptation. Here, we describe changes to the ribosome that occurred during evolution of chloroplasts from cyanobacteria in the photosynthetic lineage based on structural, proteomic and bioinformatic analyses. We identify structural features common to oxygenic photosynthetic organisms and distinct from other bacteria, as well as the gain and loss of ribosomal proteins, rRNA modifications and hibernation factors upon endosymbiosis. We uncover structural variation among land plant lineages at sites that remodel the peptide exit tunnel and features associated with translation initiation. The data challenge the prevailing view of ribosomal features that are specific to the chloroplast by demonstrating that many originated earlier, in cyanobacteria, or later, during land plant evolution.

biochemistry↗

bioRxiv2024

Towards community-driven visual proteomics with large-scale cryo-electron tomography of Chlamydomonas reinhardtii

In situ cryo-electron tomography (cryo-ET) has emerged as the method of choice to investigate structures of biomolecules in their native context. However, challenges remain in the efficient production of large-scale cryo-ET datasets, as well as the community sharing of this information-rich data. Here, we applied a cryogenic plasma-based focused ion beam (cryo-PFIB) instrument for high-throughput milling of the green alga Chlamydomonas reinhardtii, a useful model organism for in situ visualization of numerous fundamental cellular processes. Combining cryo-PFIB sample preparation with recent advances in cryo-ET data acquisition and processing, we generated a dataset of 1829 reconstructed and annotated tomograms, which we provide as a community resource to drive method development and inspire biological discovery. To assay the quality of this dataset, we performed subtomogram averaging (STA) of both soluble and membrane-bound complexes ranging in size from >3 MDa to [~]200 kDa, including 80S ribosomes, Rubisco, nucleosomes, microtubules, clathrin, photosystem II, and mitochondrial ATP synthase. The majority of these density maps reached sub-nanometer resolution, demonstrating the potential of this C. reinhardtii dataset, as well as the promise of modern cryo-ET workflows and open data sharing towards visual proteomics.

cell biology↗

bioRxiv2022

Interdigitated immunoglobulin arrays form the hyperstable surface layer of the extremophilic bacterium Deinococcus radiodurans

Deinococcus radiodurans is an atypical diderm bacterium with a remarkable ability to tolerate various environmental stresses, partly because of its complex cell envelope encapsulated within a hyperstable surface layer (S-layer). Despite decades of research into this cell envelope, atomic structural details of the S-layer have remained obscure. In this study, we report the electron cryomicroscopy structure of the D. radiodurans S-layer, showing how it is formed by the Hexagonally Packed Intermediate-layer (HPI) protein arranged in a planar hexagonal lattice. The HPI protein forms an array of immunoglobulin-like folds within the S-layer, with each monomer extending into the adjoining hexamer, leading to a highly interconnected, stable, sheet-like arrangement. Using electron cryotomography and subtomogram averaging from focused ion beam-milled D. radiodurans cells, we obtained a structure of the cellular S-layer, showing how this HPI S-layer coats native membranes on the surface of cells. Our S-layer structure from the diderm bacterium D. radiodurans shows similarities to immunoglobulin-like domain-containing S-layers from monoderm bacteria and archaea, highlighting shared traits in cell surface organization across different domains of life, with connotations on the evolution of immunoglobulin-based molecular recognition systems in eukaryotes.

microbiology↗

bioRxiv2022

A multi-domain connector links the outer membrane and cell wall in deep-branching bacteria

Deinococcus radiodurans is a deep-branching extremophilic bacterium that is remarkably tolerant to numerous environmental stresses, including large doses of ultraviolet radiation and extreme temperatures. It can even survive in outer space for several years. This endurance of D. radiodurans has been partly ascribed to its atypical cell envelope comprising an inner membrane, a large periplasmic space with a thick peptidoglycan (PG) layer, and an outer membrane (OM) covered by a surface layer (S-layer). Despite intense research, molecular principles governing envelope organization and OM stabilization are unclear in D. radiodurans and related bacteria. Here, we report an electron cryomicroscopy (cryo-EM) structure of the abundant D. radiodurans OM protein SlpA, showing how its C-terminal segment forms homotrimers of 30-stranded {beta}-barrels in the OM, whereas its N-terminal segment forms long, homotrimeric coiled coils linking the OM to the PG layer via S-layer homology (SLH) domains. Using the power of structure prediction and sequence-based bioinformatics, we further show that SlpA-like proteins are widespread in deep-branching Gram-negative bacteria, plausibly constituting an ancestral superfamily of OM-PG connectors, important for organizing the cell envelopes of many bacteria. Finally, combining our atomic structures with tomography of cell envelopes, we report a model for the cell surface of D. radiodurans, with implications on understanding the cell surface organization and hyperstability of D. radiodurans and related bacteria. Furthermore, the widespread occurrence of SlpA-like OM-PG connectors in deep-branching bacteria will help in understanding the evolutionary transition between Gram-negative and Gram-positive bacteria.

microbiology↗