SUNY at Albany
June 19-23, 2001
A crystallographic map of the transition from B-DNA to A-DNA
The mechanism for the transition between B-DNA and A-DNA, first observed nearly 50 years ago, has remained largely unresolved. We have now mapped this transformation through a set of single-crystal structures of the sequence d(GGCGCC)2, with various intermediates being trapped by methylating or brominating the cytosine bases. The resulting pathway progresses through 13 conformational steps, with a novel composite structure which pairs A-nucleotides with complementary B-nucleotides serving as a distinct transition intermediate. The details of each step in the conversion of B-DNA to A-DNA is thus revealed at the atomic level, placing intermediates for this and other sequences in the context of a common pathway.
Jeffrey M. Vargason(1), Keith Henderson(2), and P. Shing Ho(1,*)
Department of Biochemistry and Biophysics(1), ALS 2011, Oregon State University, Corvallis, OR 97331
Macromolecular Crystallography Facility at the Advanced Light Source(2), Physical Biosciences Division, MS 6-2100, Lawrence Berkeley National Laboratory, Berkeley, CA 94720