Deep-diving whales could steer the way for synthetic blood, and it’s a tiny protein in the mammoth muscle of the ocean behemoth that may hold the key.
A whale’s deep dives are an incredible feat of aquatic engineering: Their heart rate slows, their breathing ceases and blood shunts to the major organs of their body. But a much less obvious physiological phenomenon is also occurring. Whales draw on a large store of oxygen from their muscles in the form of myoglobin. These proteins act like little oxygen tanks inside muscle cells. Deep-diving mammals such as whales have a particularly high abundance of them ready to use for their plunge into the deep.
Myoglobin is not a new discovery, but its bounty in deep-diving mammals has spurred a flurry of research in recent decades. This particular study has been part of a 20-year quest by biochemist John Olson and his colleagues at Rice University to develop synthetic blood for trauma patients. The work is published in the Journal of Biological Chemistry.
"Whales and other deep-diving marine mammals can pack 10-20 times more myoglobin into their cells than humans can, and that allows them to 'download' oxygen directly into their skeletal muscles and stay active even when they are holding their breath,” said Olson in a statement.
The shape of myoglobin. The green portion indicates the “waterproof pocket” that holds heme, a molecule that allows myoglobin to bind oxygen. Credit: Jeff Fitlow/Rice University
The researchers found that whales not only harbor plenty of myoglobin, but they also possess exceptionally stable versions that tend to maintain their shape. When compared with human myoglobin, whale myoglobin is 60 times more stable.
Olson believes that this stability that’s so crucial to the whales’ deep dives is also key to the development of synthetic blood. That’s because the greater the stability, the more apoprotein – a version of myoglobin that doesn't contain the oxygen-binding molecule heme – the scientists can make.
"The reason whale meat is so dark is that it's filled with myoglobin that is capable of holding oxygen,” said Olson. “But when the myoglobin is newly made, it does not yet contain heme. We found that the stability of heme-free myoglobin is the key factor that allows cells to produce high amounts of myoglobin.”
The researchers' work with myoglobin is a model for their ultimate aim of creating synthetic hemoglobin – the related protein found in red blood cells that carries oxygen around the body. They hope to use genetically-engineered bacteria to make a version hemoglobin that can work outside of a red blood cell. If they are successful, then it may be possible to create synthetic blood for life-saving transfusions. If so, it would contribute to a much-needed blood supply. While more than 100 million blood donations are collected globally, even that massive number is not nearly enough to meet demand, according to the World Health Organization.
The life-saving possibilities goes both ways: Currently, seven out of the 13 great whale species are endangered or vulnerable. This new study provides yet another reason to preserve these mammoths of the sea, as we have yet to dip a toe into the awesome potential of our aquatic underworld.
While scientists are still oceans away from creating synthetic blood, research into this amazing protein is definitely worth a deeper look.
For a more detailed explanation, check out the video by Rice University below.