Nobel Prizes put Biochemistry in the spotlight

The Nobel Prizes recently announced in Physiology/Medicine and Chemistry both highlight the key contribution Biochemistry is making to advances in medicine and our understanding of the inner workings of the cell.

Molecular model of a bacterial ribosome. credit: MRC Lab of Molecular Biology, Wellcome Images

Molecular model of a bacterial ribosome. credit: MRC Lab of Molecular Biology, Wellcome Images

Reflecting the huge breadth of the field, the Nobel Laureates called upon a wide range of techniques as well as model organisms to probe two essential chemical processes in the cell.

Venkatraman Ramakrishnan, Thomas Steitz, and Ada Yonath were jointly awarded the Chemistry Prize1 for their tireless efforts to understand one of the most fundamental processes in the cell, the translation of DNA into proteins. This is the third Nobel Prize to recognise key milestones in our understanding of how inheritance is conveyed at the molecular level.

Over a period of more than 20 years starting at the end of the 1970s, the three researchers worked to elucidate the atomic structure of the ribosome, a complex piece of cellular machinery which is made up of more than 80 different proteins and RNA molecules.

The ribosome takes the messenger RNA molecule which has been copied from a gene and translates this into a protein. This process is going on continuously in cells and is responsible for producing the several tens of thousands of proteins that build and control an organism's cells, tissues and organs.

The three Nobel Laureates overcame significant technical hurdles to produce 3D models of the ribosome using a method called X-ray crystallography. Just the sheer size of the ribosome had led many people to conclude that this would be an impossible task.

Knowing the structure of every one of the hundreds of thousands of atoms that make up the ribosome has had important medical consequences.

Many antibiotics block the action of bacterial ribosomes but leave their human counterparts unscathed. Researchers have used the information about ribosome structure to understand the ways in which antibiotics can bind to their target and to help develop new antibiotics in the fight against bacteria.

Elizabeth Blackburn, Carol Greider and Jack Szostak, who jointly share the Nobel Prize for Physiology/Medicine2, solved a biological problem which had intrigued researchers for many years - how cells ensure that their chromosomes remain complete and intact during the cell's lifetime and through cell division.

The researchers discovered that the answer lies at the ends of the chromosome, the telomeres3. Telomeres contain a unique DNA sequence repeated several times that protect the chromosome from degradation. An enzyme called telomerase works alongside, refreshing the ends by adding on this sequence4.

Although the work was initially done in simple single-cell organisms, it soon became apparent that telomeres and telomerase exist in all organisms and carry out the same function.

The discovery of a completely novel process in the cell caused excitement in the scientific world and stimulated many promising lines of investigation. Researchers have gone on to show a role for telomeres and telomerase in ageing and cancer. Telomerase may prove to be a valuable target for therapeutic development against cancer.

  1. Nobel Prize for Chemistry: Venkatraman Ramakrishnan, MRC Laboratory of Molecular Biology, Cambridge, UK; Thomas Steitz, Howard Hughes Medical Institute & Yale University, USA; Ada Yonath, Weizmann Institute of Science, Rehovot, Israel. Awarded 'for studies of the structure and function of the ribosome'.
  2. Noble Prize for Physiology or Medicine: Elizabeth Blackburn, University of California San Francisco, USA; Carol Greider, Johns Hopkins University School of Medicine, Baltimore, USA; Jack Szostak, Harvard Medical School, Boston, USA. Awarded for 'for the discovery of how chromosomes are protected by telomeres and the enzyme telomerase'.
  3. Szostak, J.W. and Blackburn, E.H. Cloning yeast telomeres on linear plasmid vectors. Cell 29:245-255 (1982).
  4. Greider, C.W. and Blackburn, E.H. Identification of a specific telomere terminal transferase activity in Tetrahymena extracts. Cell 43:405-413 (1985).
    Greider C.W. and Blackburn, E.H. A telomeric sequence in the RNA of Tetrahymena telomerase required for telomere repeat synthesis. Nature 337:331-337 (1989).





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