Metal Retardation
Mostrando 13-24 de 24 artigos, teses e dissertações.
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13. Asparagine 212 is essential for abasic site recognition by the human DNA repair endonuclease HAP1.
HAP1 is a divalent cation-dependent endonuclease from human cells with specificity for apurinic/apyrimidinic (AP) sites in DNA. Extraction of the essential metal ion from purified HAP1 stabilized its binding to an oligonucleotide containing a single AP site, permitting AP site binding studies to be undertaken using gel retardation assays. Binding of HAP1 to
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14. Mechanism for iron-regulated transcription of the Escherichia coli cir gene: metal-dependent binding of fur protein to the promoters.
The molecular basis for the greatly elevated expression of the cir gene (encoding the colicin I receptor) in cells unable to maintain a critical supply of intracellular iron was investigated by genetic and biochemical means. Deletion analysis of the cloned promoter region allowed delineation of sequences necessary for control of transcription initiating at t
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15. The positive and negative regulation of Tn10 transposition by IHF is mediated by structurally asymmetric transposon arms
The Tn10 transpososome has symmetrical components on either side: there are two transposon ends each of which has binding sites for a monomer of transposase and an IHF heterodimer. The DNA bending activity of IHF stimulates assembly of an intermediate with tightly folded transposon ends in which transposase has additional ‘subterminal’ DNA contacts, loca
Oxford University Press.
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16. Zn2+-sensing by the cyanobacterial metallothionein repressor SmtB: different motifs mediate metal-induced protein-DNA dissociation.
SmtB is a member of a family of repressors which dissociate from DNA in the presence of metals; Zn2+ being the most potent inducer of metallothionein gene (smtA) transcription in vivo. In Synechococcus PCC 7942 cells devoid of chromosomal smtB, four plasmid-encoded mutants of SmtB (C61S, T11S/C14S, C121S and H105R/H106R) repressed lacZ expression driven by t
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17. Biochemical characterization of I-CmoeI reveals that this H-N-H homing endonuclease shares functional similarities with H-N-H colicins
Endonuclease assays of the H-N-H proteins encoded by two group I introns in the Chlamydomonas moewusii chloroplast psbA gene revealed that the CmpsbA·1 intron specifies a site-specific DNA endonuclease, designated I-CmoeI. Like most previously reported intron-encoded endonucleases, I-CmoeI generates a double-strand break near the insertion site of its encod
Oxford University Press.
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18. The metallochaperone Atox1 plays a critical role in perinatal copper homeostasis
Copper plays a fundamental role in the biochemistry of all aerobic organisms. The delivery of this metal to specific intracellular targets is mediated by metallochaperones. To elucidate the role of the metallochaperone Atox1, we analyzed mice with a disruption of the Atox1 locus. Atox1−/− mice failed to thrive immediately after birth, with 45% of pu
The National Academy of Sciences.
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19. The zinc ion in the HNH motif of the endonuclease domain of colicin E7 is not required for DNA binding but is essential for DNA hydrolysis
The HNH motif was originally identified in the subfamily of HNH homing endonucleases, which initiate the process of the insertion of mobile genetic elements into specific sites. Several bacteria toxins, including colicin E7 (ColE7), also contain the 30 amino acid HNH motif in their nuclease domains. In this work, we found that the nuclease domain of ColE7 (n
Oxford University Press.
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20. A small single-"finger" peptide from the erythroid transcription factor GATA-1 binds specifically to DNA as a zinc or iron complex.
Sequence-specific DNA binding has been demonstrated for a synthetic peptide comprising only one of the two "finger"-like domains of the erythroid transcription factor GATA-1 (also termed Eryf-1, NF-E1, or GF-1). Quantitative analysis of gel-retardation assays yields a specific association constant of 1.2 x 10(8) M, compared with values of about 10(9) M for t
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21. Rp-phosphorothioate modifications in RNase P RNA that interfere with tRNA binding.
We have used Rp-phosphorothioate modifications and a binding interference assay to analyse the role of phosphate oxygens in tRNA recognition by Escherichia coli ribonuclease P (RNase P) RNA. Total (100%) Rp-phosphorothioate modification at A, C or G positions of RNase P RNA strongly impaired tRNA binding and pre-tRNA processing, while effects were less prono
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22. Modular structure of sodium-coupled bicarbonate transporters
Mammalian genomes contain 10 SLC4 genes that, between them, encode three Cl–HCO3 exchangers, five Na+-coupled HCO3 transporters (NCBTs), one reported borate transporter, and what is reported to be a fourth Cl–HCO3 exchanger. The NCBTs are expressed throughout the body and play important roles in maintaining intracellular and whole-body pH, as well a
Company of Biologists.
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23. Distinct Roles of RAG1 and RAG2 in Binding the V(D)J Recombination Signal Sequences
The RAG1 and RAG2 proteins initiate V(D)J recombination by introducing double-strand breaks at the border between a recombination signal sequence (RSS) and a coding segment. To understand the distinct functions of RAG1 and RAG2 in signal recognition, we have compared the DNA binding activities of RAG1 alone and RAG1 plus RAG2 by gel retardation and footprint
American Society for Microbiology.
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24. The fragile X syndrome d(CGG)n nucleotide repeats form a stable tetrahelical structure.
The fragile X mental retardation syndrome is associated with the expansion of trinucleotide 5'-d(CGG)-3' repeats within the FMR1 gene and with hypermethylation of the cytosine residues of these repeats. The expansion and hypermethylation may account for the suppression of the transcription of the FMR1 gene and for the delay of its replication during the cell