Titanic Protein Gives Muscles Structure and Bounce

摘要

An athlete with a biological bent may pause a moment while lifting weights or taking a jog to appreciate the molecular choreography that takes place when muscles contract: the ratchetlike sliding actions of filaments made of actin and myosin molecules. But few athletes are likely to know the identity of another key muscle protein, the molecule responsible for their muscles' ability to spring back into shape after being stretched. While this protein does not have the name recognition of actin and myosin, it does have its own claim to fame. It is the largest protein known, a single chain of nearly 27,000 amino acids, with a molecular weight of about 3 million. Fevlother proteins have molecular weights grever than 200,000.