Scientists have discovered the largest known protein in biology. The funky PKZILLA-1 protein has been found in algae cells and helps them produce toxins responsible for mass killing of fish.
Most proteins in nature are a few nanometers (nm) long and have an average mass of about 50 kilodaltons (kDa) for complex organisms. But the newly discovered protein is a beast in comparison: PKZILLA-1 can reach 1,250 nm in length and tips the scales at 4,730 kDa. That means it has comfortably stolen the crown from the previous record holder — a human muscle protein called titin, which measured up to 1,000 nm and 3,990 kDa.
Tim Fallon, PhD
“This is the Mount Everest of proteins,” said Bradley Moore, senior author of the study. “This expands our understanding of what biology can do.”
A new and large protein has been discovered in a common type of algae. Prymnesium parvumor golden algae. PKZILLA-1, along with a smaller but still relatively large protein called PKZILLA-2, was found to help the algae produce a toxin called prymnesin. This toxin has been linked to mass fish kills when golden algae blooms in a waterway.
The PKZILLA proteins are actually enzymes, so they produce the toxin through a series of chemical reactions. This chain reaction also turned out to be quite long – the team found that 239 chemical reactions took place between the two forms of PKZILLA to produce prymnesin.
Uncovering this process could help scientists develop more accurate tests for golden algae in waterways, as well as inspire new ways to produce complex chemicals ourselves.
“Understanding how nature has developed its chemical wizardry gives us the ability as scientists to apply those insights to create useful products, whether it’s a new cancer drug or a new fabric,” Moore said.
The research was published in the journal Science.
Source: UC San Diego, via Phys.org