Related Experiment Video
Updated: Jun 24, 2026

Transmembrane Domain Oligomerization Propensity determined by ToxR Assay
Published on: May 26, 2011
[Polymorphism of tox and dtxR genes in circulating strains of Corynebacterium diphtheriae]
Abstract:
Polymorphism of tox and dtxR genes responsible for diphtheria toxin synthesis was revealed. Seven point mutations in tox gene were detected; study of their combinations allowed to determine 10 allelic variants of the tox gene in C. diphtheriae strains. Majority of mutations did not lead to changes in substitutions in amino acid sequence of diphtheria toxin. In tox gene from 2 strains of mitis biovar, ribotype "Otchakov" isolated in Saint-Petersburg, mutation in position 1252 (G --> C), which corresponds to change of glycine on arginine in amino acid sequence of diphtheria toxin (G393R), was identified. Mutation localizes in R domain of fragment B of diphtheria toxin. In the dtxR gene 16 point mutations were registered; study of their combinations allowed to determine 10 allelic variants of the dtxR gene. Two mutations led to amino acid substitutions in regulatory protein DtxR: in position 640 (C --> A), which corresponds to change of leucine on isoleucine (L2141), and in position 440 (C --> T), which corresponds to change of alanine on valine (A147V). Mutation A147V is characteristic for all strains of epidemic clonal group (strains of biovar gravis, ribotype "Sankt-Peterburg/Rossija", enzyme types of complex 8), dominated in Russia during diphtheria epidemic at 1990s. Strains of this group were characterized by high level of diphtheria toxin production.
Related Concept Videos
Diphtheria
Exon Recombination
Exon shuffling follows “splice frame rules.” Each exon has three reading...
Bacterial Toxins
Types of Toxins
Air pollutants, primarily gases, pose significant threats to respiratory health, leading to conditions like hypoxia, lung cancer, and in extreme cases, death.
Environmental pollutants like...
Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase
Repressible Operon: trp Operon

