Nobel Chemistry Prize - 2009

The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Chemistry for 2009 jointly to Venkatraman Ramakrishnan, Thomas A. Steitz and Ada E. Yonath, "for studies of the structure and function of the ribosome".

The Ribosome – a complex structure

The human body is built from approximately one hundred thousand billion cells. Each cell contains thousands of ribosomes, which are composed of a small and a large subunit. The subunits are built from rRNA-molecules, constructed from nucleotides, and proteins, made from amino acids. Nucleotides and amino acids, in turn, are built from atoms. In all, a ribosome is built from hundreds of thousands of atoms.

The ribosome connects about ten amino acids per second
Thomas Steitz has taken snapshots of different steps in the chemical reaction where amino acids are connected. The reaction is catalysed by the large subunit. Thanks to work of Thomas Steitz, scientists now know which atoms in the ribosome are involved in the various reaction steps.

Proteins control life

In the human body there are tens of thousands of proteins that build and control life at the chemical level. Examples of proteins are oxygen-transporting haemoglobin, hormones such as insulin and the antibodies of the immune system. Proteins are built from 20 different kinds of amino acids which are linked together in long chains. A protein chain can consist of anything from ten to tens of thousands of amino acids.



The ribosome – a target for new antibiotics
Today, humans have an arsenal of different antibiotics which can be used in the fight against disease-generating bacteria. Many of these antibiotics kill bacteria by blocking the functions of their ribosomes. However, bacteria have become resistant to most of these drugs at an
ominous rate. Therefore we need new ones.

This year’s three Nobel Laureates in chemistry have all produced structures that show how different antibiotics bind to the ribosome. Some of them block the tunnel through which the growing proteins leave the ribosome, others prevent the formation of the peptide bond between amino acids. Still others corrupt the translation from DNA/RNA-language into protein language.

Several companies now use the structures of the ribosome in order to develop new antibiotics. Some of these are currently undergoing clinical tests, in order to come to grips with the problem of multiresistant bacteria (e.g. MRSA).