Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The secondary structure of the isolated tRNA-like sequence (n=159) present at the 3' OH terminus of turnip yellow mosaic virus RNA has been established from partial nuclease digestion with S1 nuclease and T1, CL(3), and Naja oxiana RNases. The fragment folds into a 6-armed structure with two main domains. The first domain, of loose structure and nearest the 5' OH terminus, is composed of one large arm which extends into the coat protein cistron. The second, more compact domain, is composed of the five other arms and most probably contains the structure recognized by valyl-tRNA synthetase. In this domain three successive arms strikingly resemble the T[unk], anticodon, and D arms found in tRNA. Near the amino-acid accepting terminus, however, there is a new stem and loop region not found in standard tRNA. This secondary structure is compatible with a L-shaped three-dimensional organization in which the corner of the L and the anticodon-containing limb are similar to, and the amino-acid accepting region different from, that in tRNA. Ethylnitrosourea accessibility studies have shown similar tertiary structure features in the T[unk] loop of tRNA and in the homologous region of the viral RNA.
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PMID:The tRNA-like structure of turnip yellow mosaic virus RNA: structural organization of the last 159 nucleotides from the 3' OH terminus. 1645 15

Primary and secondary structures of mammalian mitochondrial (mt) tRNAs are divergent from canonical tRNA structures due to highly skewed nucleotide content and large size variability of D- and T-loops. The nonconservation of nucleotides involved in the expected network of tertiary interactions calls into question the rules governing a functional L-shaped three-dimensional (3D) structure. Here, we report the solution structure of human mt-tRNA(Asp) in its native post-transcriptionally modified form and as an in vitro transcript. Probing performed with nuclease S1, ribonuclease V1, dimethylsulfate, diethylpyrocarbonate and lead, revealed several secondary structures for the in vitro transcribed mt-tRNA(Asp) including predominantly the cloverleaf. On the contrary, the native tRNA(Asp) folds into a single cloverleaf structure, highlighting the contribution of the four newly identified post-transcriptional modifications to correct folding. Reactivities of nucleotides and phosphodiester bonds in the native tRNA favor existence of a full set of six classical tertiary interactions between the D-domain and the variable region, forming the core of the 3D structure. Reactivities of D- and T-loop nucleotides support an absence of interactions between these domains. According to multiple sequence alignments and search for conservation of Leontis-Westhof interactions, the tertiary network core building rules apply to all tRNA(Asp) from mammalian mitochondria.
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PMID:Tertiary network in mammalian mitochondrial tRNAAsp revealed by solution probing and phylogeny. 1976 15

We have analyzed the region of the chloroplast genome from P. sativum which encodes the 5'-end of psbA. S1 nuclease mapping and primer extension analysis of chloroplast RNA revealed psbA transcripts with 5'-termini 92, 93 and 68 nucleotides upstream from the psbA open reading frame. The psbA transcripts with 5'-ends 92-93 nucleotides upstream from the psbA open reading frame can be labeled with alpha-(32)P-GTP by guanylyltransferase. DNA sequences 10 and 35 bp upstream from the longest psbA transcript showed homology to -10 and -35 consensus promoter sequences in E. coli. Truncated psbA constructs which contain the putative psbA promoter sequences were shown to promote transcription in E. coli from a site similar to that used by chloroplast RNA polymerase in vivo. Accurate transcription of psbA constructs was also observed in a homologous in vitro transcription extract from chloroplasts. Sequence analysis of the region upstream from the psbA transcripts revealed a putative 3'-exon of a tRNA-Lys (240 bp upstream) and an unidentified open reading frame (URF, 485 bp upstream). The 3'-end of the URF mRNA was located approximately 240 bp from the 5'-end of the longest psbA transcript indicating that the URF and tRNA-Lys sequence are cotranscribed. Comparison of P. sativum and N. tabacum DNA sequences at the 5'-end of psbA revealed homology between sequences coding for psbA mRNA including 40 bp upstream from the longest psbA transcript. A second region of homology which includes the tRNA-Lys sequence was also located. In contrast the intergenic DNA exhibited extensive divergence in size and sequence. re]19850627 rv]19851211 ac]19851216.
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PMID:Characterization of P. sativum chloroplast psbA transcripts produced in vivo, in vitro and in E. coli. 2430 22


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