Tag: chemistry (page 2 of 3)

nobel prize in chemistry

The Nobel Prize in Chemistry was awarded to two Americans today for their work with G Protein Coupled Receptors. G-Protein Coupled receptors are ubiquitous in biological systems and are responsible for sending the signals that help us detect changes in our environment. They are especially important in neurotransmission and hormone signaling pathways. Also, half of known pharmaceutical targets are G-Protein coupled receptors. From the Nobel press release:

Your body is a fine-tuned system of interactions between billions of cells. Each cell has tiny receptors that enable it to sense its environment, so it can adapt to new situtations. Robert Lefkowitz and Brian Kobilka are awarded the 2012 Nobel Prize in Chemistry for groundbreaking discoveries that reveal the inner workings of an important family of such receptors: G-protein–coupled receptors.

For a long time, it remained a mystery how cells could sense their environment. Scientists knew that hormones such as adrenalin had powerful effects: increasing blood pressure and making the heart beat faster. They suspected that cell surfaces contained some kind of recipient for hormones. But what these receptors actually consisted of and how they worked remained obscured for most of the 20th Century.

Lefkowitz started to use radioactivity in 1968 in order to trace cells’ receptors. He attached an iodine isotope to various hormones, and thanks to the radiation, he managed to unveil several receptors, among those a receptor for adrenalin: β-adrenergic receptor. His team of researchers extracted the receptor from its hiding place in the cell wall and gained an initial understanding of how it works.

The team achieved its next big step during the 1980s. The newly recruited Kobilka accepted the challenge to isolate the gene that codes for the β-adrenergic receptor from the gigantic human genome. His creative approach allowed him to attain his goal. When the researchers analyzed the gene, they discovered that the receptor was similar to one in the eye that captures light. They realized that there is a whole family of receptors that look alike and function in the same manner.

Today this family is referred to as G-protein–coupled receptors. About a thousand genes code for such receptors, for example, for light, flavour, odour, adrenalin, histamine, dopamine and serotonin. About half of all medications achieve their effect through G-protein–coupled receptors.

Also, check out the New York Times.

 

nanopeople

A class of molecules called NanoPutians are designed to resemble the human form.

In a project that combines art and science, a research group at Rice University in Houston have created a class of anthropomorphic molecules. At  the school’s Department of Chemistry and Center for Nanoscale Science and Technology Stephanie Chanteau and James Tour have designed a full array of 2nm long chemicals that resemble the human form.  They call the molecules NanoPutians. The array includes monomers, dimers and even longer polymer chains of these molecules. The two in the picture appear to be doing some sort of celebratory happy dance. The researchers originally came up with the idea in 2003. This is one of the cutest chemistry projects I’ve come across in quite a while. Kudos to the Rice university scientists for having a little fun with chemistry. Check out the link for the source article, which is behind an ACS paywall, and click here to see free pictures of more of these cute little molecules.

how opioids work

A morphine-like molecule (in yellow) binds to a pocket in the mu-opiod receptor (in blue). Image from Science News. Provided by the Kobilka Lab at Stanford University.

Ever wonder how opioid drugs work their magic? Drugs like morphine, codeine and heroin? Lots of people have. And two groups of scientists, one  at Stanford and one at Scripps, have made progress in figuring out how they ease pain and cause addiction. The Stanford group crystallized a morphine like molecule with the mu opioid receptor protein. Excerpted from Sceince News:

Many of today’s most powerful painkillers work by switching on one of these proteins, called the mu opioid receptor. But the relief this provides comes at a price. Derivatives of opium, such as morphine and codeine, are addictive and can cause breathing problems and constipation.

To better understand how these drugs work, an international team of researchers for the first time crystallized a small morphinelike molecule attached to a mu receptor — a technically difficult task that requires isolating the pair of molecules without unsticking them from each other. X-rays revealed how one molecule lined up with the other.

This study has limitations though: the molecule they crystallized deactivates the receptor instead of activating it like morphine or codeine, so the interactions they are looking at might not necessarily be the same interactions that are important in easy pain or causing addiction.

The Scripps group looks at a different opioid receptor, the kappa-opioid receptor. Their crystal structure reveals the binding interactions of the experimental drug JDTic with kappa-opioid receptor. This receptor is linked to stress responses moreso than pain relief, so it should tell a different story than the other.

Exciting stuff! I can’t wait to get my hands on the actual research papers.

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