A link between our body's energy levels and a protein that wraps our DNA?

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A link between our body's energy levels and a protein that wraps our

DNA?

20 Jun 2005 Medical News Today

Living organisms need to sense the amount of energy that is available

to them and regulate the activity of their genes accordingly.

Scientists have made the unexpected finding that a histone protein,

which wraps DNA into tight bundles and regulates gene activity, can

bind a small molecule produced in our cells. This novel finding in

itself was a breakthrough for researchers at the European Molecular

Biology Laboratory (EMBL), but what made it more interesting was

which specific molecule it binds - one from a pathway known to be

linked to obesity and aging.

The EMBL researchers studied a pathway involving an enzyme (Sir2),

whose activity is regulated by the availability of nutrients, and an

energy molecule (NAD). This pathway, and the enzyme Sir2 in

particular, has been heavily investigated because nutrients are known

to regulate Sir2's activity on genes.

" Each enzyme's job is to turn starting materials into final products.

These usually have important functions, but while several scientists

have studied the enzyme Sir2, no one has identified a role for one of

the final products of the reaction in humans, " says EMBL Group Leader

s Ladurner.

When Sir2 binds to NAD, it breaks down the energy molecule into

smaller components. What the EMBL researchers found was that one of

these components plugs neatly into a special pocket of the histone

that the researchers were studying.

This discovery is the first evidence of a small compound binding

directly to a histone. As the activity of Sir2 is regulated by the

amount of food and nutrients, this finding suggests the existence of

a direct link between one of the products of the Sir2 pathway and

gene regulation.

" It is very exciting that a histone should be able to recognize one

of the compounds that Sir2 produces. We are now looking at how such a

small molecule may be able to tweak our genes and therefore our

body's response to changes in the availability of food and energy, "

Ladurner says.

European Molecular Biology Laboratory (EMBL)

http://www.embl-heidelberg.de

SOURCE: http://www.alphagalileo.org