Major Advance Made on DNA Structure.

(From AScribe)

CORVALLIS, Ore. -- Oregon State University researchers have made significant new advances in determining the structure of all possible DNA sequences -- a discovery that in one sense takes up where Watson and Crick left off, after outlining in 1953 the double-helical structure of this biological blueprint for life.

One of the fundamental problems in biochemistry is to predict the structure of a molecule from its sequence -- this has been referred to as the "Holy Grail" of protein chemistry.

Today, the OSU scientists announced in the Proceedings of the National Academy of Sciences that they have used X-ray crystallography to determine the three-dimensional structures of nearly all the possible sequences of a macromolecule, and thereby create a map of DNA structure.

As work of this type expands, it should be fundamentally important in explaining the actual biological function of genes -- in particular, such issues as genetic "expression," DNA mutation and repair, and why some DNA structures are inherently prone to damage and mutation.

Understanding DNA structure, the scientists say, is just as necessary as knowing gene sequence. The human genome project, with its detailed explanation of the genetic sequence of the entire human genome, is one side of the coin. The other side is understanding how the three-dimensional structure of different types of DNA are defined by those sequences, and, ultimately, how that defines biological function.

"There can be 400 million nucleotides in a human chromosome, but only about 10 percent of them actually code for genes," said Pui Shing Ho, professor and chair of the OSU Department of Biochemistry and Biophysics. "The other 90 percent of the nucleotides may play different roles, such as regulating gene expression, and they often do that through variations in DNA structure."