PMID:5330222
| Citation |
Müller-Hill, B (1966) Suppressible regulator constitutive mutants of the lactose system in Escherichia coli.J. Mol. Biol. 15:374-6 |
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| Abstract |
No abstract in PubMed |
| Links | |
| Keywords |
Enzyme Repression; Escherichia coli; Galactosidases; Genetic Code; Guanidines; Lactose; Molecular Biology; Mutation; Purines; RNA, Messenger |
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Main Points of the Paper
- Suppressors of nonsense codons exist for the regulatory i gene of the lactose operon, thereby proving that the functional i product is a protein.
- Rationale: suppression of nonsense codons into amino acids occurs at the translational level
- Specific activity of β-galactosidase in the wild type is 12; in both the suppressible (but unsuppressed) constitutives 18,000.
- values in a large number of different su+ revertants from these two constitutive strains range from 600 to 2000, indicating incomplete suppression and the existence of different suppressors.
Materials and Methods Used
Please list the materials and methods used in this paper (strains, plasmids, antibodies, etc).
- Mutagenesis of E.coli strain 112-12 (gal-, cys-, his-, su)
- Mutagen-producing agents: 2-aminopurine or N-methyl-N'-nitro-N-nitrosguanidine
- ONPG solution to select for lac constitutive mutants
Phenotype Annotations
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| Species | Taxon ID | Strain | Gene (if known) | OMP | Phenotype | Details | Evidence | Notes |
|---|---|---|---|---|---|---|---|---|
|
Escherichia coli |
NCBI:562 |
112-12lacI-(c) |
su |
Growth |
colonies on D-galactose + L-histidine plates (revertants to su+) |
Plating Assay |
in text, pg. 374 | |
|
Escherichia coli |
NCBI:562 |
112-12lacI-(c) |
lacI |
Expression |
decreased beta-galactosidase level (nonsense mutation present in lacI gets suppressed in the presence of su+) |
Biochemical Assay |
in text, pg. 374 | |
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