In bacteria, archaea, and the eukaryote nucleus, the endonuclease ribonuclease P (RNase P) is composed of a catalytic RNA that is assisted by protein subunits. Holzmann et al. (2008) now provide evidence that the human mitochondrial RNase P is an entirely protein-based enzyme.

RNase P is the enzyme that removes 5' leader sequences from precursor tRNAs. Remarkably, in most organisms, RNase P is a ribonucleoprotein particle where the RNA component is responsible for catalysis. In this issue of Genes & Development, Gutmann and colleagues (pp. 1022-1027) report the first organism, Arabidopsis thaliana, to employ protein-only RNase P in both its nucleus and organelles. An...

The effect of 2’-cytidylic acid and 3’qtidylic acid upon the binding of cupric ions by RNase has been studied by gel filtration, together with the effect of cupric ions upon binding of 2’and 3’-cytidylic acids. The results confirm that binding of 2’-CMP by RNase weakens its athnity for cupric ions; reciprocally, binding of cupric ion diminishes the athnity of RNase for 2’CMP. The negative inter...

RNase L is a regulated endoribonuclease that functions in the interferon antiviral response. Activation of RNase L by 2', 5'-oligoadenylates has been linked to apoptosis, autophagy and inflammation. Genetic studies have also suggested the possible involvement of the RNase L gene (RNASEL) on chromosome 1q25.3 in several types of cancer. Here we report that ablation of RNase L in human prostate c...

Escherichia coli RNase D and RNase II have been purified to homogeneity and compared for their ability to remove extra nucleotides following the -C-C-A sequence in tRNA precursors. RNase D and RNase II are single-chain proteins with molecular weights of 38,000 and 78,000, respectively. Both enzymes require a divalent cation for activity on tRNA precursors, but, in addition, RNase II is stimulat...

Bovine seminal RNase (BS-RNase) is a dimeric RNase selectively cytotoxic for malignant cells. No information is available on its pathway from the extracellular matrix through the cytosol, where it degrades rRNA. An investigation of this pathway is reported here, carried out by immunofluorescence studies, by assessing the effects on BS-RNase cytotoxicity of drugs that affect specific intracellul...

SARS-Cov-2 In der Zuschrift aus S. 21830 berichten Xinjing Tang et al. über die effiziente Hemmung von SARS-CoV-2 mit chimären Antisense-Oligonukleotiden durch Aktivierung RNase L.

The x-ray crystal structure of a 417-nt ribonuclease P RNA from Bacillus stearothermophilus was solved to 3.3-A resolution. This RNA enzyme is constructed from a number of coaxially stacked helical domains joined together by local and long-range interactions. These helical domains are arranged to form a remarkably flat surface, which is implicated by a wealth of biochemical data in the binding ...

RNase P is the enzyme that removes 5' extensions from tRNA precursors. With its diversity of enzyme forms-either protein- or RNA-based, ranging from single polypeptides to multi-subunit ribonucleoproteins-the RNase P enzyme family represents a unique model system to compare the evolution of enzymatic mechanisms. Here we present a comprehensive study of substrate recognition and cleavage-site se...

g]ycoproteins and their amino acid compesitions are significantly different from that of RNase Le2. In addition to these enzyines, a guanylic acid-specific RNase with a molecular mass 13 kDa was panially purified. Since RNase Le2, which has yery similar IVLterminat sequence to RNase Le 37 and RNase Le 45, was not excreted from the mycelia, the analysis of the structures of these two excreted RN...