Protein synthesis (translation) consumes a substantial proportion of cellular resources, prompting specialized mechanisms to reduce translation under adverse conditions. Ribosome inactivation often involves ribosome-interacting proteins. In both bacteria and eukaryotes, various ribosome-interacting proteins facilitate ribosome dimerization or hibernation, and/or prevent ribosomal subunits from associating, enabling the organisms to adapt to stress. Despite extensive studies on bacteria and eukaryotes, understanding factor-mediated ribosome dimerization or anti-association in archaea remains elusive. Here, we present cryo-electron microscopy structures of an archaeal 30S dimer complexed with an archaeal ribosome dimerization factor (designated aRDF), from Pyrococcus furiosus, resolved at a resolution of 3.2 Å. The complex features two 30S subunits stabilized by aRDF homodimers in a unique head-to-body architecture, which differs from the disome architecture observed during hibernation in bacteria and eukaryotes. aRDF interacts directly with eS32 ribosomal protein, which is essential for subunit association. The binding mode of aRDF elucidates its anti-association properties, which prevent the assembly of archaeal 70S ribosomes.

• MeSH
• Archaeal Proteins * chemistry   metabolism   genetics   ultrastructure   MeSH
• Dimerization MeSH
• Cryoelectron Microscopy MeSH
• Ribosome Subunits, Small, Archaeal * chemistry   metabolism   ultrastructure   MeSH
• Models, Molecular MeSH
• Protein Multimerization MeSH
• Pyrococcus furiosus * metabolism   genetics   MeSH
• Ribosomal Proteins * chemistry   metabolism   ultrastructure   genetics   MeSH
• Ribosomes * metabolism   chemistry   MeSH
• Protein Binding MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Archaeal Proteins * MeSH
• Ribosomal Proteins * MeSH

Palladium and silver nanoparticles (NPs) anchored at the outer surface of ferritin form stable suspension of non-coated particles that possess several catalytic and enzymomimetic activities. These activities are strongly affected by detergents that significantly influence the reaction efficiency and specificity. Reductive dehalogenation of various azo dye substrates shows strong differences in reactivity for each substrate-detergent pair. Reductive dehalogenation is negatively influenced by cationic detergents while catalytic depropargylation is severely impaired by polyethylene oxide containing detergents that is an important finding in respect to potential biorthogonal applications. Moreover, Suzuki-Miyaura reaction is promoted by polyethylene oxide containing detergents but some of them also facilitate dehalogenation. Enzymomimetic peroxidase activity of silver NPs can be detected only in presence of sodium dodecyl sulfate (SDS) while peroxidase activity of palladium NPs is enhanced by SDS and sodium deoxycholate.

• Keywords
• Detergents, Enzymomimetic activity, Ferritin, Palladium nanoparticles, Silver nanoparticles,
• MeSH
• Biomimetics * MeSH
• Detergents chemistry   MeSH
• Ferritins chemistry   metabolism   MeSH
• Catalysis MeSH
• Metal Nanoparticles chemistry   MeSH
• Palladium chemistry   metabolism   MeSH
• Peroxidase chemistry   metabolism   MeSH
• Surface Properties MeSH
• Pyrococcus furiosus chemistry   metabolism   MeSH
• Silver chemistry   metabolism   MeSH
• Particle Size MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Detergents MeSH
• Ferritins MeSH
• Palladium MeSH
• Peroxidase MeSH
• Silver MeSH

Rubredoxin from the hyperthermophile Pyrococcus furiosus (Pf Rd) is an extremely thermostable protein, which makes it an attractive subject of protein folding and stability studies. A fundamental question arises as to what the reason for such extreme stability is and how it can be elucidated from a complex set of interatomic interactions. We addressed this issue first theoretically through a computational analysis of the hydrophobic core of the protein and its mutants, including the interactions taking place inside the core. Here we show that a single mutation of one of phenylalanine's residues inside the protein's hydrophobic core results in a dramatic decrease in its thermal stability. The calculated unfolding Gibbs energy as well as the stabilization energy differences between a few core residues follows the same trend as the melting temperature of protein variants determined experimentally by microcalorimetry measurements. NMR spectroscopy experiments have shown that the only part of the protein affected by mutation is the reasonably rearranged hydrophobic core. It is hence concluded that stabilization energies, which are dominated by London dispersion, represent the main source of stability of this protein.

• MeSH
• Calorimetry MeSH
• Protein Conformation MeSH
• Nuclear Magnetic Resonance, Biomolecular MeSH
• Pyrococcus furiosus chemistry   MeSH
• Rubredoxins chemistry   isolation & purification   MeSH
• Protein Folding MeSH
• Temperature * MeSH
• Protein Structure, Tertiary MeSH
• Thermodynamics MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Names of Substances
• Rubredoxins MeSH