A new metal detector to study human disease

March 21, 2006

Zinc may be a familiar dietary supplement to millions of health-conscious people, but it remains a mystery metal to scientists who study zinc’s role in Alzheimer’s disease, stroke and other health problems.

They are just beginning to fathom how the body keeps levels of zinc under the precise control that spells the difference between health and disease.

Researchers now have developed a biochemical metal detector to help crack the mystery. It is a biosensor that has yielded the first measurements of the tiny amounts of zinc ordinarily present inside living cells.

The study appears in the current issue of ACS Chemical Biology, the newest of 34 journals published by the American Chemical Society, the world’s largest scientific organization.

It was conducted by Rebecca A. Bozym and Richard B. Thompson, Ph.D. of the department of biochemistry and molecular biology, University of Maryland School of Medicine, Baltimore, and Andrea K. Stoddard and Carol A. Fierke, Ph.D. of the Department of Chemistry, University of Michigan, Ann Arbor.

“The question of how much zinc is available in a cell has emerged at the forefront of chemical biology,” Amy R. Barrios, Ph.D., of the University of Southern California, Los Angeles, wrote in an accompanying Point of View in ACS Chemical Biology.

Barrios described the new research as “a critical step forward,” and predicted “many more exciting breakthroughs” in measuring levels of metals in human cells.

Just 2-3 grams of zinc (the weight of a penny coin) exist in the entire human body. The metal is a key building block in enzymes and other substances involved in functioning of the nervous system, the immune response, and the reproductive system.

“We believe this new technique can help us understand how zinc is involved in plaque formation in Alzheimer’s disease, how prolonged seizures or stroke kill brain cells, and how the cell normally allocates zinc to different proteins,” said Thompson.

Thompson explained that almost all zinc inside cells is incorporated into proteins, where it plays many vital roles, such as helping to read the genetic code of DNA.

“We know that if there is much zinc in the cell that is not attached to protein or otherwise encapsulated — so-called ‘free zinc’ —the cell is stressed or may be undergoing programmed cell death. This has been observed in animal models of epilepsy and stroke.”

In the past, scientists could only measure the relatively high levels of zinc in sick cells. The new sensing technology can measure very low free zinc concentrations in healthy cells.

The technique uses a special protein molecule that has been re-engineered to report when zinc becomes stuck to it as a change in luminescence that can be seen in the microscope. This protein (originally found in blood cells) is very selective, recognizing tiny levels of free zinc even in the presence of the million-fold higher levels of other metals present in cells, such as calcium or magnesium.

Because proper zinc levels are so important in health and disease, scientists have been seeking ways of measuring zinc inside and outside of cells for more than a decade.

“This is an important discovery,” said Sarah B. Tegen, Ph.D., managing editor of ACS Chemical Biology. “We need to know how the body controls levels of zinc inside cells. Too much zinc can kill nerve cells. With too little, nerve cells will not work properly.

“Now we have a metal detector, technology that can measure tiny amounts of zinc in living cells. Understanding how zinc is stored and released in different cells throughout the body may help us understand some of the nerve damage that occurs during a stroke and other nerve injuries.”

Source: American Chemical Society, by Michael Woods

Explore further: Detailed images of NMDA receptors help explain how zinc and a drug affect their function

Related Stories

Enhancing livestock immunity in a changing climate

November 14, 2016

Management and nutritional strategies are needed to protect livestock from heat stress resulting from climate change, according to a review paper published in the Pertanika Journal of Tropical Agricultural Science.

The long-sought cure to Huntington's disease

September 15, 2016

The current lack of a treatment proven effective against 'Huntington's disease' (HD) is leaving one in every 10 000 people with psychiatric, movement, feeding and communication problems that are very difficult to live with. ...

A lead to overcome resistance to antibiotics

October 6, 2016

Pseudomonas aeruginosa can become a formidable pathogen causing fatal infections, especially in intubated patients, people suffering from cystic fibrosis or severe burns. The presence of certain metals in the natural or human ...

Recommended for you

Hubble catches a transformation in the Virgo constellation

December 9, 2016

The constellation of Virgo (The Virgin) is especially rich in galaxies, due in part to the presence of a massive and gravitationally-bound collection of over 1300 galaxies called the Virgo Cluster. One particular member of ...

Hydrogen from sunlight—but as a dark reaction

December 9, 2016

The storage of photogenerated electric energy and its release on demand are still among the main obstacles in artificial photosynthesis. One of the most promising, recently identified photocatalytic new materials is inexpensive ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.