The requirement for selenium in your diet is because of its role in a small but important group of proteins called the selenoproteins. (lerner.ccf.org)
Long - term memory may depend on molecules that are oddly similar to prions, a sinister group of proteins believed to cause mad cow disease. (discovermagazine.com)
The Src homology 3 (SH3) region is a small protein domain present in a very large group of proteins, including cytoskeletal elements and signaling proteins. (science.sciencemag.org)