This animations shows how a small molecule binds to a protein to alter its shape and and make it inactivated./nSmall molecules associate or bind with a protein forming what can be thought of as a new protein. In the case shown in this animation a small molecule fits into a cleft in the protein. The blue protein, calmodulin, has several important roles in cellular function. The cleft in the shape of the protein allows it to perform many of these functions. When the gold colored small molecule binds with calmodulin it occupies this cleft and thus inactivates the protein./nIn order to understand life’s processes, it is useful to perturb the process and observe what happens./nIn genetics, a gene’s functions are investigated by using mutations that disrupt their normal function. Chemical genetics is an analogous approach that investigates the functions of the genes by using small molecules to perturb the proteins—which are encoded by the genes—directly./nIn genetics, some mutations result in loss of function, while others result in a gain of function. In chemical genetics, analogous protein perturbations exist that inactivate a protein (loss of function) or super-activate a protein (gain of function)./nSmall molecules associate with, or bind to, a protein in specific ways. In some cases they modulate the protein’s function by inactivating it. In this animation, a small molecule (in gold) binds to the protein calmodulin (in blue). Calmodulin is a protein that is involved in calcium regulation in a cell and has many important roles in cellular function. The cleft in the protein is an important site that allows it to interact with other molecules. The small molecule binds to this cleft and occupies the site, causing the protein to undergo a conformational change and become inactivated.