When most people imagine a living cell, they picture a microscopic bag of organic materials. In fact, as described in prior posts, a cell is a vast, organized society whose members constantly communicate, cooperate, negotiate, compete, and adapt to changing conditions. At the center of this society lies a remarkable transportation system: an immense network of molecular tracks, scaffolds, motors, signaling complexes, organelles, and regulatory molecules that continuously exch

Since DNA’s discovery, molecular biology had operated on reassuring assumptions: every protein folds into one precise, stable shape; shape determines its function; and shape is determined by a sequence of amino acids produced by a sequence of DNA letters. It was a clean idea. The holy grail of bioscience for decades was finding the shapes of proteins and the DNA codes that determine that shape. It is very difficult to determine the shapes of any protein from the sequence of a