Structure and function of the macrolide biosensor protein, MphR(A), with and without erythromycin
Jianting Zheng1, Vatsala Sagar, Adam Smolinsky
1Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA.
Journal of Molecular Biology
|March 7, 2009
Summary
The regulatory protein MphR(A) controls gene expression and is key in synthetic biology. Its structure reveals how erythromycin binding alters gene regulation, aiding polyketide biosynthesis.
Area of Science:
- Synthetic biology
- Molecular biology
- Structural biology
Background:
- MphR(A) is a regulatory protein used in synthetic biology for gene expression control.
- It negatively regulates the macrolide 2'-phosphotransferase I resistance gene (mphA).
- Expression is de-repressed by erythromycin binding.
Purpose of the Study:
- To present the crystal structures of MphR(A) free and bound to erythromycin.
- To investigate the DNA binding properties of MphR(A).
- To identify MphR(A) mutants affecting repression and ligand binding.
Main Methods:
- X-ray crystallography at 2.00 Å and 1.76 Å resolutions.
- DNA binding assays.
- Cell-based reporter assays for mutant analysis.
Main Results:
- Refined crystal structures of MphR(A) in apo and erythromycin-bound states.
- Characterization of MphR(A) DNA binding properties.
- Identification of mutants with impaired gene repression and erythromycin binding.
Conclusions:
- The study elucidates the molecular mechanism of erythromycin-induced gene regulation by MphR(A).
- Structural insights provide a basis for engineering MphR(A) in polyketide natural product biosynthesis.
- MphR(A) offers a framework for applications in metabolite sensing and gene expression control.
Related Concept Videos
01:25Mechanism of Antibiotic Resistance in MRSA
Antibiotic resistance in bacteria arises when microorganisms evolve the ability to withstand drugs designed to kill them or inhibit their growth, rendering once-effective treatments useless. This phenomenon, driven by genetic change and selection under antibiotic exposure, poses a profound threat to modern medicine. Mechanisms include drug-inactivating enzymes (e.g., β-lactamases), efflux pumps that eject antibiotics, mutations altering antibiotic targets, decreased drug uptake, and acquisition...
01:23Types of RNA
Overview
Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse functions and can be broadly classified as protein-coding or non-coding RNA. Non-coding RNAs play important roles in the regulation of gene expression in response to developmental and environmental changes. Non-coding RNAs in prokaryotes can be manipulated to develop more effective antibacterial drugs for human or animal use.
RNA...
Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse functions and can be broadly classified as protein-coding or non-coding RNA. Non-coding RNAs play important roles in the regulation of gene expression in response to developmental and environmental changes. Non-coding RNAs in prokaryotes can be manipulated to develop more effective antibacterial drugs for human or animal use.
RNA...
01:25Inhibitors of Bacterial Protein Synthesis
Aminoglycosides constitute a highly potent class of bactericidal antibiotics that exert their antimicrobial effects by targeting the bacterial ribosome, specifically disrupting protein synthesis. These polycationic molecules consist of amino-modified sugars linked via glycosidic bonds to an aminocyclitol core such as 2-deoxystreptamine or streptamine. Their strong positive charges facilitate tight binding to the negatively charged phosphate backbone of ribosomal RNA (rRNA), primarily at the 16S...
01:56Riboswitches
Riboswitches are non-coding mRNA domains that regulate the transcription and translation of downstream genes without the help of proteins. Riboswitches bind directly to a metabolite and can form unique stem-loop or hairpin structures in response to the amount of the metabolite present. They have two distinct regions – a metabolite-binding aptamer and an expression platform.
The aptamer has high specificity for a particular metabolite which allows riboswitches to specifically regulate...
The aptamer has high specificity for a particular metabolite which allows riboswitches to specifically regulate...