Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Modification of the histidine residues of purified S1 nuclease resulted in loss of its single-stranded (ss)DNAase, RNAase and phosphomonoesterase activities. Kinetics of inactivation indicated the involvement of a single histidine residue in the catalytic activity of the enzyme. Furthermore, histidine modification was accompanied by the concomitant loss of all the activities of the enzyme, indicating the presence of a common catalytic site responsible for the hydrolysis of ssDNA, RNA and 3'-AMP. Substrate protection was not observed against Methylene Blue- and diethyl pyrocarbonate (DEP)-mediated inactivation. The histidine (DEP)-modified enzyme could effectively bind 5'-AMP, a competitive inhibitor of S1 nuclease, whereas the lysine (2,4,6-trinitrobenzenesulphonic acid)-modified enzyme showed a significant decrease in its ability to bind 5'-AMP. The inability of the substrates to protect the enzyme against DEP-mediated inactivation, coupled with the ability of the modified enzyme to bind 5'-AMP effectively, suggests the involvement of histidine in catalysis.
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PMID:Active-site characterization of S1 nuclease. II. Involvement of histidine in catalysis. 146 60

We have further characterized the genomic region of Streptomyces coelicolor A3(2) that contains genes involved in the biosynthesis of histidine. A 2,357-base pair fragment contained in plasmid pSCH3328 that complemented hisD mutations has been sequenced. Computer analysis revealed an open reading frame that encodes a protein with significant homology to the Escherichia coli, Salmonella typhimurium and Mycobacterium smegmatis hisD product, Saccharomyces cerevisiae HIS4C, and Neurospora crassa his3 gene products. Two other contiguous open reading frames oriented divergently with respect to hisD did not show significant similarity with any of the his genes or to other sequences included in the gene bank. S1 nuclease mapping and primer extension experiments indicate that the transcription initiation site of the his-specific mRNA coincides with the GUG translation initiation codon of the hisD cistron.
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PMID:Further characterization of the histidine gene cluster of Streptomyces coelicolor A3(2): nucleotide sequence and transcriptional analysis of hisD. 148 52

The primary structure of nuclease P1, which cleaves both RNA and single-stranded DNA, from Penicillium citrinum was elucidated. The complete amino acid sequence consisting of 270 residues was determined by analysis of peptides obtained by digestion with Achromobacter protease I of the reduced and S-aminoethylated protein and by digestion with Staphylococcus aureus V8 protease of the reduced and S-carboxymethylated protein. Four half-cystine residues were assigned to Cys72-Cys217 and Cys80-Cys85. N-Glycosylated asparagine residues were identified at positions 92, 138, 184 and 197. Fast-atom-bombardment and laser-ionization MS were successfully used to confirm the determined amino acid sequences of peptides and to estimate the molecular mass of this glycoprotein having heterogenous sugar moieties, respectively. Comparison of the amino acid sequence of nuclease P1 with other nucleases revealed that the protein has a high degree of sequence identity (50%) with nuclease S1 from Aspergillus oryzae. The His-Phe-Xaa-Asp-Ala sequence (positions 60-64) is similar to the sequence (His-Phe-Asp-Ala) involving the active-site His119 of bovine pancreatic RNase A, and the Pro-Leu-His sequence (positions 124-126) is identical with the sequence involving the active-site His134 of porcine pancreatic DNase I.
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PMID:Primary structure of nuclease P1 from Penicillium citrinum. 191 39

The amino acid sequence of nuclease S1, a nuclease which cleaves both single-stranded DNA and RNA, from Aspergillus oryzae was determined. Reduced and S-carboxymethylated or S-aminoethylated nuclease S1 was digested with Achromobacter protease I, Staphylococcus aureus V8 protease, or endoproteinase Asp-N. Peptides thus obtained were purified by reverse-phase high-performance liquid chromatography and sequenced, and the complete primary structure was established. Nuclease S1 consists of a single peptide chain of 267 amino acid residues bearing N-glycosylated Asns 92 and 228. Five half-cystine residues are present at positions 25, 72, 80, 85, and 216, and the latter four residues are implicated in the formation of disulfide bonds by analogy with those in nuclease P1. Two short stretches of sequences involving His 60 and His 125 are shown to be identical with those involving active site His 119 in bovine ribonuclease A and active-site His 134 in porcine deoxyribonuclease I, respectively.
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PMID:Amino acid sequence of nuclease S1 from Aspergillus oryzae. 193 22

Histidine-tRNA synthetase is one of the smallest bacterial aminoacyl-tRNA synthetases. It is less than one-half the size of the largest aminoacyl-tRNA synthetases. The entire nucleotide sequence of the Escherichia coli hisS locus was determined. The coding region is comprised of 424 codons, and the sequence was determined for 200 nucleotides on the 5'- and 3'-sides of the coding region. The translated nucleotide sequence was confirmed extensively by independent amino acid sequence information obtained by Edman degradations of purified peptides and by measurements of peptide masses by fast atom bombardment mass spectrometry. A significant sequence alignment of four bacterial aminoacyl-tRNA synthetases was reported recently (Webster, T., Tsai, H., Kula, M., Mackie, G., and Schimmel, P. (1984) Science 226, 1315-1317). Although the four enzymes vary considerably in length, this match occurs within the first 100 amino acids of each of the four enzymes and is in the segment believed to be part of the catalytic core. But no strong alignment could be found of the histidine sequence with these four tRNA synthetase sequences. This enzyme may be derived, therefore, from a different progenitor. Previous work suggested that three places in the hisS 5'-noncoding sequence could be promoter sites for RNA polymerase (Eisenbeis, S. J., and Parker, J. (1982) Gene 18, 107-114). We detected a 1400-nucleotide RNA species by RNA blot analysis with a hisS-specific probe. S1 nuclease mapping demonstrated a 5'-end to the RNA species occurs at -67 +/- 1, relative to the first nucleotide of the coding region. This position coincides with the predicted start site for transcription from one of the previously proposed promoter sites.
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PMID:Primary structure of histidine-tRNA synthetase and characterization of hisS transcripts. 299 Dec 72

Recombinant cDNA clones representing the carboxy-terminal portion of the histidine-rich protein of Plasmodium lophurae and the 3' untranslated region of the mRNA have been sequenced. Histidine accounts for 78% of the predicted amino acid sequence. The DNA and protein sequences in this region differ significantly from published sequences deduced from cloned genomic DNA of P. lophurae. Sequence data from two independent cDNA clones, comparison of restriction endonuclease sites present in genomic DNA, genomic and cDNA clones, gene titrations, S1 nuclease digestion of cDNA-mRNA hybrids and comparison of predicted and published data for the amino acid composition of the histidine-rich protein all suggest that P. lophurae contains one histidine-rich protein gene and that the sequence of the 3' coding region of this gene has been correctly deduced from the cDNA clones.
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PMID:Structure and organization of the histidine-rich protein gene of Plasmodium lophurae. 300 81

We have determined the complete nucleotide sequence of the histidine operons of Escherichia coli and of Salmonella typhimurium. This structural information enabled us to investigate the expression and organization of the histidine operon. The proteins coded by each of the putative histidine cistrons were identified by subcloning appropriate DNA fragments and by analyzing the polypeptides synthesized in minicells. A structural comparison of the gene products was performed. The histidine messenger RNA molecules produced in vivo and the internal transcription initiation sites were identified by Northern blot analysis and S1 nuclease mapping. A comparative analysis of the different transcriptional and translational control elements within the two operons reveals a remarkable preservation for most of them except for the intercistronic region between the first (hisG) and second (hisD) structural genes and for the rho-independent terminator of transcription at the end of the operon. Overall, the operon structure is very compact and its expression appears to be regulated at several levels.
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PMID:Structure and function of the Salmonella typhimurium and Escherichia coli K-12 histidine operons. 306 74

Adenosine deaminase (ADA; adenosine aminohydrolase, EC 3.5.4.4) deficiency is one cause of the genetic disease severe combined immunodeficiency. To identify mutations responsible for ADA deficiency, we synthesized cDNAs to ADA mRNAs from two cell lines, GM2756 and GM2825A, derived from ADA-deficient immunodeficient patients. Sequence analysis of GM2756 cDNA clones revealed a different point mutation in each allele that causes amino acid changes of alanine to valine and arginine to histidine. One allele of GM2825A also has a point mutation that causes an alanine to valine substitution. The other allele of GM2825A was found to produce an mRNA in which exon 4 had been spliced out but had no other detrimental mutations. S1 nuclease mapping of GM2825A mRNAs showed equal abundance of the full-length ADA mRNA and the ADA mRNA that was missing exon 4. Several of the ADA cDNA clones extended 5' of the major initiation start site, indicating multiple start sites for ADA transcription. The point mutations in GM2756 and GM2825A and the absence of exon 4 in GM2825A appear to be directly responsible for the ADA deficiency. Comparison of a number of normal and mutant ADA cDNA sequences showed a number of changes in the third base of codons. These changes do not affect the amino acid sequence. Analyses of ADA cDNAs from different cell lines detected aberrant RNA species that either included intron 7 or excluded exon 7. Their presence is a result of aberrant splicing of pre-mRNAs and is not related to mutations that cause ADA deficiency.
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PMID:Mutations in the human adenosine deaminase gene that affect protein structure and RNA splicing. 347 10

The nucleotide sequence of the yeast gene TRP5 and its 5' and 3' flanking regions was determined. The deduced coding sequence for tryptophan synthase contains 2,127 base pairs. The protein chain has a calculated molecular weight of 76,544. Yeast tryptophan synthase, a bifunctional protein, has a primary structure which corresponds to an Escherichia coli tryptophan synthase alpha chain-beta chain fusion. An NH2-terminal 239 amino acid segment of yeast tryptophan synthase is homologous with E. coli tryptophan synthase alpha subunit, while a distal 389 amino acid residue segment is homologous to the E. coli tryptophan synthase beta chain. This order of segments of the yeast enzyme is the reverse of the chromosomal order characteristic of all prokaryotes that have been examined. The two segments are joined by a connecting region of 28 residues in the yeast enzyme which is not homologous to either the alpha or beta chains of the bacterial enzyme. A portion of the connecting region of yeast tryptophan synthase exhibits nucleotide sequence similarity to the 3' terminus of E. coli trpC and the trpC-trpB intercistronic region. Active site cysteine, histidine, and lysine residues in the beta 2 subunit of E. coli tryptophan synthase are conserved in the yeast enzyme. Also conserved in the yeast enzyme are 6/8 amino acid residues having an important role in maintaining the structure and function of the E. coli tryptophan synthase alpha subunit. S1 nuclease mapping was used to identify three major mRNA transcripts with different 5' termini. Potential T-A-T-A sites for transcription initiation were identified, as well as other sequences that occur frequently in yeast genes. A 5' flanking region of TRP5 was shown by DNA/DNA hybridization to be present in multiple copies in the yeast genome. TRP5 mRNA levels, measured by RNA/DNA hybridization, increased 2- to 7-fold in response to starvation for either tryptophan or histidine, indicating transcriptional regulation.
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PMID:Yeast gene TRP5: structure, function, regulation. 627 87

The operator-distal genes hisBHAFI(E) of the Escherichia coli K-12 histidine operon were mapped on a DNA fragment 4,500 base pairs long. This fragment, originally present in a lambda transducing phage, was cloned in the vector plasmid pBR313. A restriction map was determined, allowing identification of the orientation of the genes in the fragment. The cloned genes were expressed in appropriate hosts, independent of the orientation of the DNA fragment, as shown by transformation tests and by enzyme assays of one of the gene products, hisB, histidinol phosphatase. An internal transcription initiation site was identified by isolation of the cellular RNA, hybridization to specific DNA probes, and mapping by S1 nuclease.
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PMID:Cloning and expression of the distal portion of the histidine operon of Escherichia coli K-12. 628 8


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