Study in PNAS shows that each shape has a unique role in attracting and activating white blood cells.
Researchers at the Medical College of Wisconsin in Milwaukee found that a protein, lymphotactin, which plays a role in the body’s immune response, can rapidly shift its shape between two totally unrelated structures, each with a unique role in defending the body.
Using highly sensitive NMR spectroscopy to solve 3-D protein structures, the team discovered that human lymphotactin exists naturally in two distinct structures. They say that the newly-identified form has no similarity to any other known protein. The investigators also learned that each form has a unique role, one attaching to the interior wall of the blood vessel and the other reaching out to grab white blood cells.
“Proteins often have multiple functional states that are closely related to a single structure” says team leader, Brian Volkman, Ph.D., associate professor of biochemistry. “In its natural state, however, we found that lymphotactin adopts two equally populated but unrelated structures that rapidly change from one to the other.”
The study is published in the Proceedings of the National Academy of Science.
