The discovery of the double helical structure of DNA by Watson and Crick in the 1950s ushered in the modern field of molecular biology, and since then molecular and cell biologists have become proponents of the "gene product theory of human disease." Instead of examining microbial invaders, for example, the biomedical research community studies the consequences of introducing foreign proteinssuch as fungal, bacterial and viral virulence factorsinto humans, or the results of genetic mutations that disrupt the function of normal genes.
This molecular view of disease has contributed to the importance of studies of the three-dimensional structure of proteins using techniques such as X-ray crystallography and nuclear magnetic resonance spectroscopy, which allow researchers to visualize the various shapes that enable proteins to perform their vital functions.
Although the human genome is estimated to contain about 100,000 genes, with each gene encoding one protein, there are not a corresponding 100,000 shapes into which the proteins can fold. In fact, scientists now estimate that there are only 1,000 to 5,000 distinct spatial arrangements of polypeptide chains found in nature.
While some researchers fear that structural genomics will put X-ray crystallographers and nuclear magnetic resonance (NMR) spectroscopists out of business, Sali and his colleagues contend that technological advances will improve the efficiency of all structural biologists. They also argue that structural genom
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