Dtn
Mostrando 25-31 de 31 artigos, teses e dissertações.
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25. The binding of poly (rA) and poly (rU) to denatured DNA. II. Studies with natural DNAs.
We have studied the interaction of poly(rA) and poly(rU) with natural DNAs containing (dA.dT)n sequences. The results indicate that hybridization of poly(rA) to denatured DNA can be used to estimate the size and frequency of large (dA.dT)n tracts, whereas hybridization with poly(rU) does not give reliable information on these points. In 6.6 M CsCl, poly(rU)
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26. Protein synthesis and competitive ESR binding studies with E. coli ribosomes and spin-labeled polynucleotides.
Enzymatically prepared spin labeled copolymers of (U)n were tested for their ability to direct polyphenylalanine synthesis in vitro using E. coli B enzymes and ribosomes. Spin labeling of the C5 position using (RUGT,U)n (1:100) or (RUTT,U)n (1:100) did not alter the amount of polyphenylalanine formed in comparison to (U)n. In contrast, the C4 spin labeled co
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27. Review: ethidium fluorescence assay. Part II. Enzymatic studies and DNA-protein interactions.
Almost all DNA and RNA metabolizing enzymes can be assayed rapidly and very sensitively by exploiting the enhanced fluorescence of ethidium intercalated into duplex DNA or RNA. Denatured DNA and natural RNAs contain duplex regions due to intramolecular hydrogen-bonding and can also be sensitively measured. Where the product is truly single-stranded (e.g. dTn
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28. The elongation of mismatched primers by DNA polymerase alpha from calf thymus.
The ability of the 9S and 5.7S DNA polymerase alpha subspecies from calf thymus in elongating a mismatched primer terminus has been investigated. With poly(dA) as template, the elongation rate for (dT)8dG, (dT)8dC and (dT)10dGdT is 20-fold lower for the 9S enzyme and 5-fold lower for the 5.7S enzyme as compared to (dT)10. The presence of a second mismatch at
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29. Mung bean nuclease cleavage of a dA + dT-rich sequence or an inverted repeat sequence in supercoiled PM2 DNA depends on ionic environment.
We have determined the nucleotide sequences around two alternative sites cleaved in supercoiled PM2 DNA by single-strand-specific mung bean nuclease in different ionic environments. In 10 mM Tris-HC1 (pH 7.0, 37 degrees C), the major site is a dA+dT-rich sequence which maps with a known early denaturation region at 0.75 map units. About 30 cleavages occurred
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30. Translesional synthesis on a DNA template containing N2-methyl-2′-deoxyguanosine catalyzed by the Klenow fragment of Escherichia coli DNA polymerase I
Formaldehyde is produced in most living systems and is present in the environment. Evidence that formaldehyde causes cancer in experimental animals infers that it may be a carcinogenic hazard to humans. Formaldehyde reacts with the exocyclic amino group of deoxyguanosine, resulting in the formation of N2-methyl-2′-deoxyguanosine (N2-Me-dG) via reducti
Oxford University Press.
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31. Regeneration of insertionally inactivated streptococcal DNA fragments after excision of transposon Tn916 in Escherichia coli: strategy for targeting and cloning of genes from gram-positive bacteria.
The conjugative transposon Tn916 (15 kilobases), originally identified in Streptococcus faecalis DS16, has been cloned as an intact element on the pBR322-derived vector pGL101 in Escherichia coli. The EcoRI F' (EcoRI F::Tn916) fragment of pAM211 (pAD1::Tn916) was cloned into the single EcoRI site of pGL101 to form the chimera, pAM120, by selecting for the ex