PMID: 8601840Mar 15, 1996Paper

In vivo interaction between mutated tryptophan repressors of Escherichia coli

Journal of Molecular Biology
N StorbakkM R el-Gewely

Abstract

By expressing a mutant trpR gene in an Escherichia coli strain that is trpR and has beta-galactosidase activity fused to the trp promoter/operator, thus putting the beta-galactosidase activity under the control of the Trp repressor, we can determine quantitatively the relative repression activity of such mutant(s). We used this technique to analyse the biological consequences of substituting certain amino acid residues in only one of the two corepressor binding pockets. By combining two compatible plasmids in this strain, one expressing the mutant T44M and the other expressing only one substitution at a time at position 85, we analysed the repression activity of the resulting interactions in vivo. This approach allowed us to engineer active dimer repressors made of two inactive or partially active monomers. Amino acid substitutions at position 85 with a positive or with an indole ring (W) appeared to complement T44M, which amino acids with a negative charge did not. Only L substitution at position 85 appeared to restore activity among the hydrophobic amino acids tested. Similar to the wild-type repressor activity, the successful mutant-mutant interactions were L-tryptophan dependent. In vivo regulation by three known L-tryptoph...Continue Reading

Citations

Mar 30, 1999·Nature Biotechnology·M R El-Gewely
Jan 24, 1998·Biochemical and Biophysical Research Communications·C FentonM R el-Gewely

❮ Previous
Next ❯

Related Concepts

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.