Scientists like to actually see the things they research. But this isn't always possible. Source: Clipart ETCClipart ETC
Source: WikipediaWikipedia Most of what we see is larger than the wavelength of visible light. Scientists occasionally want to study things that are smaller than the wavelength of visible light. Wavelength of ultraviolet light: 400 nanometers One nanometer = one millionth of a millimeter
That was the case with the ribosome that Nobel Prize laureate Prof. Ada Yonath wanted to explore. The diameter of a ribosome is about 20 nanometers, which is approximately 20 times smaller than the ultraviolet wavelength. Wavelength of ultraviolet light: 400 nanometers One nanometer = one millionth of a millimeter
To "see" the internal structure of bodies the size of a ribosome, scientists often expose them to x-rays. This reveals the location of single atoms. The wavelength of x-rays is about 20 times smaller than the diameter of ribosomes. Source: NASANASA
The ribosome is a key component of living cells. Source: WikipediaWikipedia
Living cells have a single nucleus and thousands of ribosomes. Source: WikipediaWikipedia
Ribosomes translate the genetic information within the cell's nucleus into a process for producing proteins. Source WikipediaWikipedia
Proteins are huge molecules, structured like folding chains and composed of a sequence of amino acids. Source: WikipediaWikipedia
Proteins are one of the most important compounds that make up living organisms. They are found in every living cell. Ribosomes themselves are composed, in part, of proteins Source: Clipart ETCClipart ETC
Prof. Ada Yonath and other researchers wanted to know which proteins are contained in the ribosome and how they are organized spatially. To find out, they needed to rely on x-rays. Source: Prof' Ada Yonaths' LabProf' Ada Yonaths' Lab
The method for determining the structure of biological molecules using radiation is called x-ray crystallography. Prof. Ada Yonath uses x-ray crystallography to study ribosomes. Source NASANASA
To prepare a living substance for x-ray crystallography research, the substance itself needs to be crystallized. Source: Prof' Ada Yonaths' LabProf' Ada Yonaths' Lab
Different crystals diffract the x-rays directed at them in different ways. The particular composition and spatial structure of each crystal create a unique picture. This picture resembles a collection of dots. Source: WikipediaWikipedia
All the pictures created during x-raying are entered into powerful computers, which feed them into a complex decoding process resulting in three-dimensional images. The computer-assisted decoding relies on mathematical formulas and hypothetical structural models, based on data gathered through other methods. Source: WikipdiaWikipdia
As the x-raying proceeds, it is crucial to maintain the stability of the substance being examined. In many cases, the substance is deformed due to the strong radiation it receives, similar to the way living tissues are harmed in an X-ray test. Because of the radiation, the substance changes form, preventing the researcher from determining its structure.
Prof. Ada Yonath was the first to deal successfully with two complex problems: crystallizing the ribosome and preparing the crystal for x-ray without changing its form during the examination process. Source: L'OREAL-UNESCO Awards For Women in ScienceL'OREAL-UNESCO Awards For Women in Science
The living substance that Prof. Yonath used to examine ribosome structure was bacteria that live in hot springs or in the Dead Sea, which are resistant to high temperatures. Prof. Yonath cooled samples of the substance to a temperature of -185º C, preventing its decomposition under experimental conditions.
This accomplishment earned her the 2009 Nobel Prize for Chemistry. She shared the prize with Thomas Steitz of Yale University in the U.S. and Venkatraman Ramakrishnan of Cambridge University in Britain. The three scientists were awarded the prize for their contribution to the study of ribosome structure and functioning.
Most antibiotic medicines attach themselves to bacterial ribosomes, preventing them from acting. By understanding how antibiotics affect ribosomes, scientists can conduct research leading to the development of more effective drugs. Source: The lab of Prof' Ada YonathThe lab of Prof' Ada Yonath
Writing: Hanan Cohen Editing: Nurit Snir Graphic design: Vadik Bakman Many thanks to Prof. Ada Yonath for her comments on this presentation