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RNase P (rnase + p)
Selected AbstractsExtensive deproteinization of Dictyostelium discoideum RNase P reveals a new catalytic activityFEBS JOURNAL, Issue 7 2001Constantinos Stathopoulos Nuclear Dictyostelium discoideum RNase P was subjected to vigorous deproteinization procedures. After treatment with proteinase K followed by phenol extraction of samples containing D. discoideum RNase P activity, a new enzymatic activity was recovered. The proteinase K/phenol/SDS treated enzyme cleaves Schizossacharomyces pombe tRNAser (supS1), D. discoideum tRNASer and tRNALeu precursors several nucleotides upstream of the cleavage site of RNase P, liberating products with 5,-hydroxyl ends. This activity seems to be associated with one or two RNA molecules copurifying with D. discoideum RNase P activity as judged by its inhibition in the presence of micrococcal nuclease, which is in contrast to its resistance to proteinase K/phenol/SDS treatment. [source] RNase P RNA-mediated cleavageIUBMB LIFE, Issue 3 2009Leif A. Kirsebom Abstract Metal(II)-induced hydrolysis of RNA produce products with 5,-hydroxyls and 2,;3,-cyclic phosphates at the ends. Ribozymes are RNA molecules that act as catalysts. Some ribozymes that cleave RNA also generate 5,-hydroxyls and 2,;3,-cyclic phosphates whereas others produces 5,-phosphates and 3,-hydroxyls at the ends of the cleavage products. RNase P is an essential endoribonuclease involved in RNA processing. The catalytic RNA subunit of RNase P is a trans-acting ribozyme that cleaves various RNA substrates in vitro generating 5,-phosphates and 3,-hydroxyls as cleavage products. The activity depends on the presence of metal(II) ions such as Mg2+. RNase P RNA has therefore to facilitate a nucleophilic attack that generates the correct product ends and prevent metal(II)-induced hydrolysis of the RNA substrate. In this review, we will discuss our current understanding of the interactions between RNase P RNA and its substrate, role of specific residues with respect to catalysis and positioning of functionally important Mg2+ at and in the vicinity of the cleavage site that ensures that products with correct ends are generated. Moreover, we will discuss the composition of RNase P and its RNA subunit in an evolutionary perspective. © 2009 IUBMB IUBMB Life, 61(3):189,200, 2009 [source] Broadening the mission of an RNA enzymeJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2009Michael C. Marvin Abstract The "RNA World" hypothesis suggests that life developed from RNA enzymes termed ribozymes, which carry out reactions without assistance from proteins. Ribonuclease (RNase) P is one ribozyme that appears to have adapted these origins to modern cellular life by adding protein to the RNA core in order to broaden the potential functions. This RNA-protein complex plays diverse roles in processing RNA, but its best-understood reaction is pre-tRNA maturation, resulting in mature 5' ends of tRNAs. The core catalytic activity resides in the RNA subunit of almost all RNase P enzymes but broader substrate tolerance is required for recognizing not only the diverse sequences of tRNAs, but also additional cellular RNA substrates. This broader substrate tolerance is provided by the addition of protein to the RNA core and allows RNase P to selectively recognize different RNAs, and possibly ribonucleoprotein (RNP) substrates. Thus, increased protein content correlated with evolution from bacteria to eukaryotes has further enhanced substrate potential enabling the enzyme to function in a complex cellular environment. J. Cell. Biochem. 108: 1244,1251, 2009. © 2009 Wiley-Liss, Inc. [source] | ||||||||||