An extracellular ribonuclease from Rhizopus stolonifer (designated as RNase Rs) was purified to homogeneity by chromatography on DEAE-cellulose followed by CM-cellulose. The Mr of the purified enzyme determined by gel filtration and SDS-PAGE is 25,000 and 28,200, respectively. RNase Rs is a glycoprotein and contains 10.5% neutral sugar. It is an acidic protein with a pI of 5.0 and has a blocked...

Ribonuclease P (RNase P) is involved in the processing of the 5' leader sequence of precursor tRNA (pre-tRNA). We have found that RNase P RNA (PhopRNA) and five proteins (PhoPop5, PhoRpp21, PhoRpp29, PhoRpp30, and PhoRpp38) reconstitute RNase P activity with enzymatic properties similar to those of the authentic ribozyme from the hyperthermophilic archaeon Pyrococcus horikoshii OT3. We report h...

Several RNases H1 cleave the RNA-DNA junction of Okazaki fragment-like RNA-DNA/DNA substrate. This activity, termed 3'-junction ribonuclease (3'-JRNase) activity, is different from the 5'-JRNase activity of RNase H2 that cleaves the 5'-side of the ribonucleotide of the RNA-DNA junction and is required to initiate the ribonucleotide excision repair pathway. To examine whether RNase H1 exhibits 3...

The genome of an extremely thermophilic bacterium, Thermus thermophilus HB8, contains a single ORF (open reading frame) encoding an RNase-HII-like sequence. Despite the presence of significant amino acid sequence identities with RNase (ribonuclease) HII enzymes, the ORF TTHA0198 could not suppress the temperature-sensitive growth defect of an RNase-H-deficient Escherichia coli mutant and the pu...

The almond, Prunus dulcis Miller which belongs to Rosaceae family, is one of the most important commercial and oldest cultivated tree nut crops. Almonds are classified as a ‘nut’ in which the edible seed is the commercial product. Therefore, pollination and fertilization are necessary in almond. The characteristic of cultivated almond to express gametophytic self- incompatibility discourages se...

RNA decay and maturation have in recent years been recognised as major regulatory mechanisms in bacteria. In contrast to Escherichia coli, the Firmicute (Gram-positive) bacteria often do not encode the well-studied endonuclease RNase E, but instead rely on the endonucleases RNase Y, RNase J1 and RNase J2, of which the latter two have additionally been shown to have 5' to 3' exonucleolytic activ...

The secondary structures of the eubacterial RNase P RNAs are being elucidated by a phylogenetic comparative approach. Sequences of genes encoding RNase P RNA from each of the recognized subgroups (alpha, beta, gamma, and delta) of the proteobacteria have now been determined. These sequences allow the refinement, to nearly the base pair level, of the phylogenetic model for RNase P RNA secondary ...

Ribonuclease A (RNase A) and the ribonuclease inhibitor protein (RI) form one of the tightest known protein-protein complexes. RNase A variants and homologues, such as G88R RNase A, that retain ribonucleolytic activity in the presence of RI are toxic to cancer cells. Herein, a new and facile assay is described for measuring the equilibrium dissociation constant (K(d)) and dissociation rate cons...