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Biochemists at the University of California, Los Angeles have unlocked the structure of telomerase, the enzyme that's been called the "biochemical elixir of youth and immortality," but which also fuels the malignant growth of cancer cells.
This is a big deal since telomerase has been so hard to find in human cells that some scientists referred to it as "that mythical enzyme."
Here's what it does: Each set of chromosomes is framed by a protective cap of DNA called a telomere. Telomeres make sure that when cells divide, no meaningful DNA sequence gets left out. But telomeres are also resposinble for shutting down old cells, i.e. aging. Like slow-burning blasting fuses, they shorten each time a cell divides. Once a telomere runs out, the cell shuts down and dies. Along with it die potentially cancerous mutations the cell accumulated with old age. But telomerase reverses this process. The enzyme restores the length of the caps and makes cells effectively immortal.
It sounds great but it's quite dangerous. That's why telomerase is turned off in the vast majority of cells in the body. It's only active in the developing embryo, germ cells, and cancer cells.
During cancer, active telomerase stokes malignant multiplication of cells and the growth of tumors. Understanding the chemical structure of telomerase and how to turn it off could launch development of new cancer drugs. "Knowledge of the structure should provide insights into how telomerase works," said Juli Feigon, professor of chemistry and biochemistry at UCLA, who led the research group. "Knowing the structure also will allow the pursuit of rational, structure-based drug design, and is a critical first step. The structure provides a potential target for drug intervention."
Feigon's findings were published in the March 4 issue of the Molecular Cell journal.