Chapter 3: Biological MoleculesBizarre Facts in Biology |
X-Ray Vision
By Kelli A. Prior
When doctors need to examine what is going on inside the human body, they often turn to X-rays to give them an answer. And now more than ever, when research scientists want an up-close look at the structure of different molecules of the body, they harness the short wavelengths of X-rays to help them as well.
The Human Genome Project gave scientists a wealth of information about the sequences of human genes and the proteins that they encode. However, knowing the sequence of a protein reveals little about its structure and function. The new Protein Structure Initiative is now aimed at determining the structure and function of thousands of proteins. This goal will depend largely on a technology known as X-ray crystallography.
X-ray crystallography has been used to determine the structure of many biologically important molecules, including DNA. In order to use this method, scientists must first synthesize a crystal form of the molecule to be tested. The X-rays that hit each atom of the crystal are diffracted and the diffraction pattern is interpreted by a computer to determine the actual arrangement of atoms in the molecule.
The applications of X-ray crystallography go beyond basic scientific interest in different protein structures. In 2002, X-ray crystallography provided “snapshots” of the structure of sodium channels in the human body, giving scientists greater insight into their dynamic tasks in human physiology. These channels play a vital role in many body functions including heart pumping and nerve impulses. X-ray crystallography is also used as a means of understanding the complex interactions between tissues of the human body and new therapeutic drugs. Researchers are hoping to use this method to design more effective treatments to combat HIV and other infectious diseases. This promising technology provides scientists with “X-ray vision” to look at the individual atoms of the human body. Many hope that it will be a stepping stone toward a better understanding of diseases and potential cures.