Isolation and characterization of mutations creating high-efficiency transcription initiation signals within the trp operon of Escherichia coli is a research paper published in Journal of Bacteriology (1976). On theSindex it has a DataRank of 0.635. It has been cited 10 times, with 6 citing works in its 1-hop citation network.
Two different mutational events generate promoter-active deoxyribonucleic acid sequences within the trp operon of Escherichia coli, probably through single base-pair changes. The mutations, obtained after ethyl methane sulfonate mutagenesis by selecting for elevated lac gene expression in a trp-lac fusion, are cis dominant and trans recessive with respect to their effects on the synthesis of downstream enzymes. One of the mutants (trpD11), obtained repeatedly under the selective conditions employed, prevents the formation of active phosphoribosyltransferase. The second mutation, trp3B, has no effects on any trp enzyme. By deletion mapping, trpD11 was localized near the operator-distal end of trpD, outside the segment of deoxyribonucleic acid that contains the low-efficiency internal promoter trpP2. Reversion to prototrophy of trpD11 was greatly stimulated by 2-aminopurine and ethyl methane sulfonate. Tests with suppressors indicated that trpD11 is a UAA (ochre) nonsense mutation. Under repression conditions, strains harboring either lesion in a normal trp operon synthesize the tryptophan biosynthetic enzymes in a noncoordinate fashion. The products of the operator-distal structural genes trpC, trpB, and trpA are formed at rates approximately 15-fold higher than those of wild type. The enzymes encoded by operator-proximal genes trpE and trpD are low or not detectable. Under derepression conditions, coordinate expression of the operon was observed.
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Base Score Contribution
0.360
From this paper's citation signal
Citation Network Contribution
0.275
From 6 citing papers with measurable signal
Ranked by citation count — the same ordering the engine uses when summing log1p(Cq) over citers.
DataRank blends this paper's own citation count with the influence of the papers that cite it. Here, roughly 57% comes from its base citations and 43% from the citation network (6 citing papers contributed measurable signal).
Citers are pulled from OpenAlex sorted by cited_by_count:descand capped per paper, so when the cap binds we keep the highest-signal references and the score is reproducible across reruns.
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