Redox regulatory system controls normal cellular functions. Controlled changes in redox couples potential serve as components for signal transduction, similarly to the phosphorylation cascade. Cellular redox biology requires both compartimentalisation and communication of redox systems: the thermodynamic disequilibrium of the major redox switches allows rapid and sensitive responses to perturba...

1. A protein factor promoting the binding of initiator tRNA to the 40S ribosomal subunit was purified to homogeneity (more than 2500-fold) from rat liver cytosol. It has a mol.wt. of 265000 and is composed of four subunits of identical molecular weight. 2. This factor directs the binding of methionyl-tRNA(fMet) and to a lesser extent also of N-acetylphenylalanyl-tRNA, but not of methionyl-tRNA(...

Unlike the chromosome of Escherichia coli that needs only one replication initiator protein (origin recognition protein) called DnaA, many plasmid replicons require dual initiators: host-encoded DnaA and a plasmid-encoded origin recognition protein, which is believed to be the major determinant of replication control. Hitherto, the relative mechanistic roles of dual initiators in DNA replicatio...

Thiol-dependent redox regulation of enzyme activity plays a central role in the rapid acclimation of chloroplast metabolism to ever-fluctuating light availability. This regulatory mechanism relies on ferredoxin reduced by the photosynthetic electron transport chain, which fuels reducing power to thioredoxins (Trxs) via a ferredoxin-dependent Trx reductase. In addition, chloroplasts harbor an NA...

Multiple binding sites for an initiator protein are a common feature of replicator sequences from various organisms. By binding to the replicator, initiators mark the site and contribute to melting or distortion of the DNA by largely unknown mechanisms. Here we analyze origin of DNA replication (ori) binding by the E1 initiator and show sequential binding to a set of overlapping binding sites. ...

The endoplasmic reticulum (ER) is a metabolically active organelle, which has a central role in proteostasis by translating, modifying, folding, and occasionally degrading secretory and membrane proteins. The lumen of the ER represents a separate compartment of the eukaryotic cell, with a characteristic proteome and metabolome. Although the redox metabolome and proteome of the compartment have ...