K. A. Chapman

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The interactions of T7 RNA polymerase with T7 late promoters were studied by using quantitative footprinting with methidiumpropyl-EDTA X Fe(II) [MPE-Fe(II)] as the DNA cleaving agent. Class II and class III T7 promoters have a highly conserved 23 base pair sequence from -17 to +6. Among class III promoters the -22 to -18 region is also highly conserved. For(More)
Nodules of tropical legumes generally export symbiotically fixed nitrogen in the form of ureides that are produced by oxidation of de novo synthesized purines. To investigate the regulation of de novo purine biosynthesis in these nodules, we have isolated cDNA clones encoding 5-aminoimidazole ribonucleotide (AIR) carboxylase and(More)
This paper describes the construction of 18 cloned bacteriophage T7 late promoters with single point mutations. In vitro transcription experiments were used to characterize the properties of these promoters. Since the mutated promoters are cloned into identical backgrounds, differences seen in the transcription assays are directly attributable to the point(More)
We isolated the ntrC gene from Bradyrhizobium japonicum, the endosymbiont of soybean (Glycine max), and examined its role in regulating nitrogen assimilation. Two independent ntrC mutants were constructed by gene replacement techniques. One mutant was unable to produce NtrC protein, while the other constitutively produced a stable, truncated NtrC protein.(More)
The construction of plasmids containing T7 class I promoters with deletion mutants was described. Restriction fragments, ending at the Hinf I site located at position -10 in the promoter from 14.8% of the T7 genome, were cloned into pBR322. This produced the deletion of either the left or the right part of the promoter. The in vitro transcription properties(More)
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