MoleClues TV: 2009 Nobel Prize in Chemistry

Duration: 3 minutes and 57 seconds

Country: Sweden

Language: English

License: CC - Attribution Non-commercial No Derivatives

Genre: Documentary

Producer: MoleClues TV

Director: Per Thoren

Views: 107 (5 embedded)

Posted by: locumele on Oct 8, 2009

The 2009 Nobel Prize in Chemistry explained easy in this video from MoleClues TV!

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MoleClues TV presents
The Nobel Prize in Chemistry 2009 explained easy:
Who won it and why?
Ribosomes can be thought of as microscopic factories in the cell
Factories making proteins
They are where the amino acids that we obtain by eating food are joined together into long chains,
which then fold into proteins that are useful either as enzymes, in cell signaling or as structural support in cells.
The recipe for making a particular protein is stored in the arrangement of the DNA bases in our genes.
To make a protein, the information in one gene is first transferred to a chemical cousin of DNA called messenger RNA (mRNA).
A ribosome consists of two major parts, known as the small subunit and the large subunit, which lock together round the mRNA.
The ribosome then scans the mRNA molecule with the help of smaller RNA molecules called transfer RNAs (tRNAs), which bring in the amino acids one by one.
The process is called translation:
The mRNA instruction is read by the ribosome and the tRNAs to make sure that the right amino acids are joined together, in the correct order –
– otherwise the protein would malfunction.
The mRNA slides through the ribosome as it is scanned, while tRNAs enter into precisely defined sites,
allowing the synthesis of the protein chain to take place.
Thanks to the winners of the 2009 Nobel Prize in Chemistry, we know quite a lot about how the ribosome is constructed and how this fantastic factory works.
These scientists have worked out the details using a technique called X-ray crystallography.
In X-ray crystallography, an X-ray beam is sent through a crystal of the molecule that is studied.
The X-rays are diffracted into different directions by the electron clouds of the various atoms in the crystal.
From the angles and intensities of these beams, it is possible to create a three-dimensional picture of where the electron clouds are located
By analyzing this electron density map, it is possible to determine the arrangement of atoms within the crystal, as well as their chemical bonds.
Obviously, the task of solving the structure becomes more complicated the larger the molecule… The ribosome is the largest structure ever solved by x-ray crystallography!
How do the tools necessary for scientists to make such advanced experiments evolve?
Through hard work, of course!
Ada Yonath, the first woman in 45 years to win the Nobel Prize in Chemistry,
is a pioneer in this field. She was the first to produce ribosome crystals.
She and her group have led the way towards accomplishing crystal structures of ribosomes with atomic resolution,
by gradually improving the technique
and solving, among other things, the structure of the small ribosomal subunit of a bacterium called Thermus thermophilus.
In 2000, Tom Steitz and coworkers were the first to crystallize the large subunit of Haloarcula marismortui,
a single-celled microorganism found in the Dead Sea, and solve its structure at atomic resolution.
They could immediately draw the important conclusion that the crucial part of the ribosome, where the translation process takes place,
consists only of RNA and not of proteins, as is otherwise typical of cellular machineries.
Knowledge of the structure of the ribosome has made it possible to make more experiments
to understand in detail how the RNA in the ribosome is involved in making proteins.
How does the ribosome make sure that the reading of the genetic message is always accurate –
– that the right tRNA is allowed to pass through the machine so that the right amino acid is added to the growing protein chain?
The third Nobel Prize winner, Venki Ramakrishnan, who also solved the structure of the small subunit,
analyzed the ribosome in complexes with tRNA and showed how this works.
He has also shown how the ribosome can be forced to make errors in the presence of certain drugs -
- which could help the development of new antibiotics.
The ribosome is an amazing molecular machine, and there is still much to discover about it!
Discuss the Nobel Prize and other things on www.MoleClues.org

MoleClues TV: 2009 Nobel Prize in Chemistry

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