The tyrB gene from Escherichia coli K-12 was cloned and sequenced, and the transcriptional start point of tyrB was determined by primer extension. By using a fusion plasmid in which the lacZ structural gene is transcribed from the tyrB promoter, it was shown that the expression of tyrB is controlled at the transcriptional level by the TyrR protein, with tyrosine as corepressor. The fusion plasmid was used to isolate mutants in which the repression of tyrB had been abolished. The tyrB promoter-operator region of these mutants was sequenced, and the tyrB operator was identified. A comparison between the tyrB operator and those of the other genes belonging to the tyrR regulon is presented.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC213844 | PMC |
| http://dx.doi.org/10.1128/jb.169.10.4710-4715.1987 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Different nitrogen conditions regulating extracellular polymeric substances and erosion resistance of sewer sediment: Mechanism of microbial metabolism and molecular response.
Chemosphere
November 2024
College of Environmental Science and Engineering, Tongji University, 200092 Shanghai, China; Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, 200092 Shanghai, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China. Electronic address:
Nitrogen biotransformation plays a vital role in the metabolism of microbial communities in sewers. Extracellular polymeric substances (EPS) secreted by microbial communities can form gel-like sewer sediments, causing clogging of the sewer. However, knowledge on the effects of varying nitrogen conditions on the erosion resistance of sewer sediments and EPS produced by sewer microorganisms is limited.
View Article and Find Full Text PDFSynthesis of aspartic acid and tyrosine by the fire blight pathogen Erwinia amylovora is not required for proliferation on apple flower stigmas or virulence in fruitlets.
J Appl Microbiol
August 2024
Department of Plant Pathology & Environmental Microbiology, The Pennsylvania State University, University Park, PA 16802, United States.
Aims: The Gram-negative bacterium Erwinia amylovora (Ea) is the causal agent of fire blight, a devastating disease of apples and pears. In the fire blight disease cycle, Ea grows in different plant tissues, each presenting a distinct nutrient environment. Here, we investigate the ability of aspartate and tyrosine double auxotroph Ea lines to proliferate on apple flower stigma surfaces representing the epiphytic growth stage of Ea and in developing fruitlets representing one endophytic growth stage of Ea.
View Article and Find Full Text PDFMetabolic Engineering of for High-Level Production of l-Phenylalanine.
J Agric Food Chem
May 2024
School of Biotechnology, Jiangnan University, Wuxi 214122, China.
Article Synopsis
- * Researchers engineered a strain called PHE03 by reconstructing the l-Phe biosynthetic pathway and then evolved it to create PHE04, which showed a 36.2% cell mortality rate after 48 hours of fermentation.
- * Transcriptional profiling identified MarA as key to improving cell tolerance to high l-Phe concentrations, leading to enhanced yields of l-Phe (80.48 g/L) in fermentation using strain PHE05.
Enzyme Commission Number Prediction and Benchmarking with Hierarchical Dual-core Multitask Learning Framework.
Research (Wash D C)
May 2023
Biodesign Center, Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 300308, Tianjin, China.
Enzyme commission (EC) numbers, which associate a protein sequence with the biochemical reactions it catalyzes, are essential for the accurate understanding of enzyme functions and cellular metabolism. Many ab initio computational approaches were proposed to predict EC numbers for given input protein sequences. However, the prediction performance (accuracy, recall, and precision), usability, and efficiency of existing methods decreased seriously when dealing with recently discovered proteins, thus still having much room to be improved.
View Article and Find Full Text PDFTranscriptomics and metabolomics analysis of L-phenylalanine overproduction in Escherichia coli.
Microb Cell Fact
April 2023
Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
Background: Highly efficient production of L-phenylalanine (L-Phe) in E. coli has been achieved by multiple rounds of random mutagenesis and modification of key genes of the shikimate (SHIK) and L-Phe branch pathways. In this study, we performed transcriptomic (16, 24 and 48 h) and metabolomic analyses (8, 16, 24, 32,40, and 48 h) based on time sequences in an engineered E.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!