 |  | 2D gel of proteins Haemophilus influenzae cell proteins separated by 2D gel electrophoresis. The basic proteins are to the right of the gel and the acidic proteins to the left. High molecular weight proteins are to the top of the gel. |
 |
 |  | Active site The active site of the penicillin-binding protein. The gray stick-like structures represent the secondary and tertiary structure of the penicillin-binding protein. Binding of the antibiotic, the substrate, to the active site blocks the normal action of the protein in the bacterial cell, resulting in death of the cell. |
 |
 |  | Alternative splicing More than one protein can be made from a gene. In this case, three different mRNA molecules are made from one gene. The exons (the numbered boxes) can combine in different configurations to eventually form different proteins. |
 |
 |  | Drug binding to active site of protein In virtual ligand screening, the three-dimensional image of the protein is fed into a computer, which attempts to fit millions of small molecules to a targeted active site. Small molecules that bind well to the protein become good leads for potential new drugs. |
 |
 |  | John Kendrew John Kendrew determined the structure of the myoglobin protein in 1957. He shared the 1962 Nobel Prize in Chemistry with Max Perutz, who determined the structure of hemoglobin. |
 |
 |  | Leroy Hood Leroy Hood, MD, PhD, developed the automated genetic sequencer in 1986 and was a strong proponent of the Human Genome Project. He is the founder and president of the Institute for Systems Biology in Seattle, Washington. |
 |
 |  | Max Perutz Max Perutz determined the structure of the hemoglobin protein in 1959. The work took him 22 years. He shared the 1962 Nobel Prize in Chemistry with John Kendrew, who discovered the structure of myoglobin. |
 |
 |  | Protein crystal To determine the structure of a protein, scientists use X-ray crystallography, a process in which they crystallize the protein and use an X ray to determine defraction patterns. |
 |
 |  | Protein interaction A network of protein-protein interactions in a yeast cell |
 |
 |  | Protein structure Primary Structure: The specific sequence of amino acids in a polypeptide chain. Secondary Structure: The folding of the polypeptide chain into specific shapes, such as the alpha helix and beta pleated sheet. Other regions of secondary structure may include turns and random coils. Tertiary Structure: The unique three-dimensional shape that is the result of chemical interactions between amino acids that fold the regions of secondary structure. Quaternary Structure: The specific interaction of two or more polypeptide subunits. |
 |