October 07, 2009

Nobel season '09: Chemistry

It's yet another great Nobel season for biology! This year's Nobel prize in Chemistry has been awarded to Venkatraman Ramakrishnan, Thomas Steitz and Ada Yonath for the isolation and crystallization of ribosomes, and the elucidation of their structure using x-ray crystallography.

These discoveries are as central as can be to biology. The ribosomes are the molecular machines that translate the genetic code into the proteins that build and carry out the physiological functions of organisms. To understand them better, how they are constructed and how they carry out their reactions, is to understand the physico-chemical foundations of life itself better. It's also nice to have yet another woman recipient this year.

Here's some info from the press release. Describing DNA as "information" or a "blueprint" is a pet peeve of mine, but I can cut them a little bit of slack since this is a press release that should be understood by everyone.

The Nobel Prize in Chemistry for 2009 awards studies of one of life's core processes: the ribosome's translation of DNA information into life. Ribosomes produce proteins, which in turn control the chemistry in all living organisms. As ribosomes are crucial to life, they are also a major target for new antibiotics.


Inside every cell in all organisms, there are DNA molecules. They contain the blueprints for how a human being, a plant or a bacterium, looks and functions. But the DNA molecule is passive. If there was nothing else, there would be no life.

The blueprints become transformed into living matter through the work of ribosomes. Based upon the information in DNA, ribosomes make proteins: oxygen-transporting haemoglobin, antibodies of the immune system, hormones such as insulin, the collagen of the skin, or enzymes that break down sugar. There are tens of thousands of proteins in the body and they all have different forms and functions. They build and control life at the chemical level.

This Nobel prize completes the trinity of the "central dogma of molecular biology": That DNA is transcribed into RNA which "carries the message" to the ribosomes where it's translated into proteins. The previous Nobel prizes were the 1962 physiology or medicine prize to James Watson, Francis Crick and Maurice Wilkins for the structure of DNA and the 2006 chemistry prize to Roger Kornberg for the structure of the DNA transcription mechanism.

The funny thing is that the ribosomes themselves shake up this "central dogma" a little bit since they are partially built up by functional RNA called ribosomal RNA or rRNA. This shows that RNA isn't simply a "relay" in the molecular machinery of cells, but also constitute an integral functional part of it. Many different categories of functional RNA molecules are known - the 2006 physiology or medicine Nobel prize was awarded Andrew Fire and Craig Mello for the discovery that some functional RNA molecules contributed to the regulation of gene expression.

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