Researchers working at The Wistar Institute report that they deciphered the 3-D structure a telomerase molecule domain essential for the activity of the enzyme.
Previous research found that telomerase is made up of multiple protein components and a stretch of RNA that is used as a template to create the short DNA repeats that are added to the ends of chromosomes.
“Studies show that if you delete the TRBD domain from telomerase, the enzyme is inactive because it can no longer assemble with RNA,” notes Emmanuel Skordalakes, Ph.D., an assistant professor in the gene expression and regulation program at Wistar and senior author of the study. “Without the RNA, the enzyme can no longer replicate telomeres.”
Dr. Skordalakes and co-workers obtained the 3-D structure of TRBD using X-ray crystallography. Their studies revealed that the TRBD domain is shaped like a boomerang, with a structural organization that leads to the formation of a narrow well-defined pocket on the surface of the protein that enables the enzyme to bind the single-stranded RNA used as a template for the DNA repeats.
A second RNA-binding site is formed by a large cavity that serves as an extension of the single-stranded, RNA-binding pocket. The extent of these RNA interactions indicates the important role of this domain in stabilizing the complex, Dr. Skordalakes adds.
The findings are published in the November 13 issue of Structure.