The research appears online today (10/27) in the journal PLoS Biology, published by the Public Library of Science.
Human cells contain enzymes called polymerases that perform the process of copying DNA. The double helix of the DNA contains the genetic instructions for building an organism, and when cells in any living being divide, they copy DNA to pass on those instructions to new cells.
During this replication, the two halves of the DNA strand separate, and each half becomes a template for a new partner. The polymerases are responsible for "reading" the templates to determine where to place nucleotides to create the matching partners resulting in the creation of two identical double helices.
Polymerases are divided among six families of enzymes based on their amino acid sequence and function: A, B, C, D, X and Y (the most recently discovered family).
The A family has been well-studied and takes care of most of the DNA copying. But enzymes in this family stall if they come across DNA damage, and that stalling endangers the replication process and could lead to cell death.
The Y family of polymerases, on the other hand, can step in to bypass damage and allow copying to continue. This keeps the cell alive but also has led scientists to wonder if these enzymes could also be a major source of mistakes.
Polymerases are attractive research subjects because they have already been used as targets in anti-cancer and anti-viral drugs, so fully understanding their behavior could open up avenues for further drug development, noted Jessica Brown, a doctoral student in the Ohio State Biochemistry Program and a co-author of the study.
"In the case of polymerases, you want to know how these dynamics relate to the correct nucleotide incorporation so you can then determine the dynamics when the wrong molecule is incorporated," Brown said.
|Contact: Zucai Suo|
Ohio State University