Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have begun an analysis in Escherichia coli of the conjugal transfer functions of the broad-host-range plasmid RP4. We have isolated 19 tra mutants of RP4, generated by insertion of transposon 7, and mapped their insertion sites by restriction endonuclease analysis. These sites fall into two separate regions on either side of the kanamycin resistance determinant. The transfer rates of the mutants range from 10% of that of RP4 to an undetectable level. Spot tests with the P-1 pilus-specific phages PRR1, Pf3, and PR4 and electron microscopic examination for pili have classified the mutants into several phenotypes consistent with their having normal, retracted, or no pili. Analysis of transient plasmid heterozygotes, created by P1 transduction, divided the tra mutants into a minimum of five complementation groups. Some of these groups contain more than one phenotypic class and may represent more than one gene because of the possible polar and deletion effects of Tn7 insertion.
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PMID:Conjugal transfer system of plasmid RP4: analysis by transposon 7 insertion. 33 95

Hybrid plasmid RP4-ColE1 was obtained by joining DNA plasmids RP4 and ColE1, each of which possessed only one site of restriction for EcoR1. These plasmid molecules were restricted by endonuclease EcoR1 and then treated by ligase. The hybrid plasmid retained the property of transmissibility typical for drug factor resistance RP4. Non-transmissible mutant of the hybrid plasmid selected by the character of the resistance of Escherichia coli C600 (RP4-ColE1) to the phage PRR1 is used for subsequent investigations.
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PMID:[Transmissible hybrid plasmid RP4-ColE1]. 79 17