Biology subjects

Kengen, S.

Publications and source records attributed to Kengen, S..

3 recordsLinked to original sources

bioRxiv2025

Structure of an oxygen-induced tubular nanocompartment in Pyrococcus furiosus

Reactive oxygen species (ROS) pose a significant threat to biological molecules, prompting organisms to develop systems that buffer oxidative stress and contain iron, which otherwise amplifies ROS production. Understanding oxidative stress responses requires identifying the key proteins involved and their cellular organization. Here, we combined proteomics and cryo-EM to investigate the response of the anaerobic hyperthermophilic archaeon Pyrococcus furiosus to oxygen exposure. Proteome analysis revealed a significant upregulation of the oxidoreductase Rubrerythrin (Rbr) under oxidative stress. Cryo-electron tomograms showed the formation of prominent oxidative stress-induced tubules (OSITs). Single-particle cryo-EM and mass spectrometry of enriched OSITs identified them as stacked rings of Rbr homotetramers. The 3.3 [A] structure demonstrates that rubredoxin-like domains mediate homotetramer assembly, suggesting that their oxidation drives OSIT formation. Within OSITs, we discovered virus-like particles formed by a ferritin-like/encapsulin fusion protein with iron hydroxide cores, uncovering a sophisticated organelle that protects P. furiosus from ROS through advanced compartmentalization.

molecular biology↗

bioRxiv2022

Thriving in the heat - Lysine acetylation stabilizes the quaternary structure of a Mega-Dalton hyperthermoactive PEP-synthase

Over time structural adaptations enabled proteins and enzymes to have sufficient stability and flexibility to perform the basic functions of life under various environmental conditions. The catalytic cores of key metabolic enzymes of hyperthermophilic archaea work at a temperature range of 80-120 {degrees}C, similar to the conditions wher the earliest life forms may have thrived. Here we characterize a key enzyme of the central carbon metabolism of Pyrococcus furious, through an integrative approach combining structural mass spectrometry, cryo-electron microscopy, mass photometry and molecular modelling with molecular dynamics simulations. From our investigation, we unveil the structural organization of phosphoenolpyruvate synthase (PPSA). Its 24-meric assembly - weighing over 2 MDa - harbors flexible distal domains, whose proper functioning and coordination depends on widespread chemical acetylation of lysine residues. This non-enzymatic post-translational modification, along with other types of lysine modifications, also occurs on most other major protein complexes of P. furiosus. These modifications likely originated in the chemically favorable primordial conditions and gradually became highly specialized and enzyme-driven in more distantly related mesophiles and Eukaryotes.

biochemistry↗

bioRxiv2021

SIBR-Cas enables host-independent and universal CRISPR genome engineering in bacteria

CRISPR-Cas is a powerful tool for genome editing in bacteria. However, its efficacy is dependent on host factors (such as DNA repair pathways) and/or exogenous expression of recombinases. In this study, we mitigated these constraints by developing a simple and universal genome engineering tool for bacteria which we termed SIBR-Cas (Self-splicing Intron-Based Riboswitch-Cas). SIBR-Cas was generated from a mutant library of the theophylline-dependent self-splicing T4 td intron that allows for universal and inducible control over CRISPR-Cas counterselection. This control delays CRISPR-Cas counterselection, granting more time for the editing event (e.g., by homologous recombination) to occur. Without the use of exogenous recombinases, SIBR-Cas was successfully applied to knock-out several genes in three bacteria with poor homologous recombination systems. Compared to other genome engineering tools, SIBR-Cas is simple, tightly regulated and widely applicable for most (non-model) bacteria. Furthermore, we propose that SIBR can have a wider application as a universal gene expression and gene regulation control mechanism for any gene or RNA of interest in bacteria.

bioengineering↗