Serpins are a superfamily of proteins with similar structures that were first recognized for their protease inhibition activity and are found in all kingdoms of life. Their unusual mechanism of action irreversibly inhibits their target protease by undergoing a large conformational change to disrupt its active site. This contrasts with the more common competitive mechanism for protease inhibitors that bind to and block access to the protease active site. Protease inhibition by serpins controls an array of biological processes, including coagulation and inflammation, and consequently these proteins are the target of medical research. Their conformational-change mechanism confers certain advantages, but it also has drawbacks: serpins are vulnerable to mutations that can result in protein misfolding and the formation of inactive long-chain polymers. Serpin polymerization not only reduces the amount of active inhibitor, but also leads to accumulation of the polymers, which can cause cell death and even organ failure.

Read more: https://en.wikipedia.org/wiki/Serpin

_______________________________ Today's selected anniversaries:

1513:

Spanish conquistador Juan Ponce de León reached Florida, becoming the first European known to do so, purportedly while searching for the Fountain of Youth in the New World. https://en.wikipedia.org/wiki/Juan_Ponce_de_Le%C3%B3n

1865:

American Civil War: On the third try, Union Army forces captured Petersburg, Virginia, although Confederate government officials and most of the remaining Confederate army were able to escape. https://en.wikipedia.org/wiki/Third_Battle_of_Petersburg

1911:

The Australian Bureau of Statistics conducted the country's first national census. https://en.wikipedia.org/wiki/Census_in_Australia

1982:

Argentine special forces invaded the Falkland Islands, sparking the Falklands War. https://en.wikipedia.org/wiki/1982_invasion_of_the_Falkland_Islands

2006:

Over 60 tornadoes touched down in the central United States, killing 27 people and causing about US$1.1 billion in damages. https://en.wikipedia.org/wiki/April_2,_2006_tornado_outbreak

_____________________________ Wiktionary's word of the day:

alligator: (obsolete) One who binds or ties. https://en.wiktionary.org/wiki/alligator

___________________________ Wikiquote quote of the day:

No theater could sanely flourish until there was an umbilical connection between what was happening on the stage and what was happening in the world.   --Kenneth Tynan https://en.wikiquote.org/wiki/Kenneth_Tynan