We use cookies to understand how you use our site and to improve your experience. This includes personalizing content and advertising. To learn more, click here. By continuing to use our site, you accept our use of cookies. Cookie Policy.

Features Partner Sites Information LinkXpress hp
Sign In
Advertise with Us
GLOBE SCIENTIFIC, LLC

Download Mobile App




Potential Tuberculosis Drug Prevents DNA Supercoiling

By LabMedica International staff writers
Posted on 28 Jan 2013
A recent paper described the molecular mechanism that allows the drug diospyrin to block the growth of the tuberculosis bacterium Mycoplasma tuberculosis.

Diospyrin is a dimeric naphthoquinone isolated from the root of Diospyros piscatoria (Gurke), a common ingredient in several folk medicines, which has been shown to have a broad spectrum of antibacterial activity. More...
Previous studies have shown that diospyrin binds to a novel site on the enzyme DNA gyrase and inactivates it. DNA gyrase is essential for bacteria and plants but is not present in animals or humans.

DNA gyrase is a type II topoisomerase that introduces negative supercoils into DNA by looping the template so as to form a crossing, then cutting one of the double helices and passing the other through it before releasing the break, changing the linking number by two in each enzymatic step. This process occurs particularly in bacteria, where single circular DNA is cut by DNA gyrase, and the two ends are then twisted around each other to form supercoils.

Supercoiling is the coiling of an already coiled structure (such as DNA). DNA is coiled around itself for several reasons: the three-dimensional structure of DNA affects its function; the coiling can have positive or negative effects on gene expression; and the unraveling of portions of a circular bacterial chromosome during transcription could induce coiling that could prevent the strands for reattaching to one another. Supercoiling in the opposite direction will cancel out coiling problems during transcription. Coiling DNA in multiple directions reduces the space occupied by DNA and makes the structure more stable during replication and transcription.

In a paper published in the December 28, 2012, online edition of the Journal of Biological Chemistry investigators at the John Innes Center (Norfolk, United Kingdom) reported that diospyrin and related naphthoquinone compounds bound to the N-terminal domain of DNA gyrase, which contains the ATPase active site, but were not competitive inhibitors of the ATPase reaction. Therefore, naphthoquinones bound to the enzyme at a previously undefined site close to the ATPase site.

"The way that diospyrin works helps to explain why it is effective against drug-sensitive and drug-resistant strains of tuberculosis," said senior author Dr. Tony Maxwell, professor of biological chemistry at the John Innes Center.

"Extracts from plants used in traditional medicine provide a source for novel compounds that may have antibacterial properties, which may then be developed as antibiotics," said Dr. Maxwell. "This highlights the value of ethnobotany and the value of maintaining biodiversity to help us address global problems."

Related Links:
John Innes Center



Gold Member
Veterinary Hematology Analyzer
Exigo H400
Serological Pipet Controller
PIPETBOY GENIUS
New
Pan-Cancer Panel
TruSight Oncology 500
New
Automated PCR Setup
ESTREAM
Read the full article by registering today, it's FREE! It's Free!
Register now for FREE to LabMedica.com and get access to news and events that shape the world of Clinical Laboratory Medicine.
  • Free digital version edition of LabMedica International sent by email on regular basis
  • Free print version of LabMedica International magazine (available only outside USA and Canada).
  • Free and unlimited access to back issues of LabMedica International in digital format
  • Free LabMedica International Newsletter sent every week containing the latest news
  • Free breaking news sent via email
  • Free access to Events Calendar
  • Free access to LinkXpress new product services
  • REGISTRATION IS FREE AND EASY!
Click here to Register








Channels

Hematology

view channel
Image: CitoCBC is the world first cartridge-based CBC to be granted CLIA Waived status by FDA (Photo courtesy of CytoChip)

Disposable Cartridge-Based Test Delivers Rapid and Accurate CBC Results

Complete Blood Count (CBC) is one of the most commonly ordered lab tests, crucial for diagnosing diseases, monitoring therapies, and conducting routine health screenings. However, more than 90% of physician... Read more

Immunology

view channel
Image: A simple blood test could replace surgical biopsies for early detecion of heart transplant rejection (Photo courtesy of Shutterstock)

Blood Test Detects Organ Rejection in Heart Transplant Patients

Following a heart transplant, patients are required to undergo surgical biopsies so that physicians can assess the possibility of organ rejection. Rejection happens when the recipient’s immune system identifies... Read more

Pathology

view channel
These images illustrate how precision oncology Organ Chips recapitulate individual patients’ responses to chemotherapy (Photo courtesy of Wyss Institute at Harvard University)

Cancer Chip Accurately Predicts Patient-Specific Chemotherapy Response

Esophageal adenocarcinoma (EAC), one of the two primary types of esophageal cancer, ranks as the sixth leading cause of cancer-related deaths worldwide and currently lacks effective targeted therapies.... Read more
Copyright © 2000-2025 Globetech Media. All rights reserved.