Structure of the A-DNA octamer d(GGCATGCC).

The crystal structure of the self-complementary DNA octamer d(GGCATGCC) has been determined to a resolution of 2.38 A and R factor of 17.1%. The structure is an A-DNA octamer duplex with Watson-Crick base pairing along its length. This sequence extends the investigation of octamer duplexes of the type d(GGX(4)CC) which assume P6(1) packing within the crystallographic unit cell. The A-DNA duplex is non-linear with a helix axis curvature of 7 degrees and bending towards the DNA minor groove. In view of the biological importance of protein recognition of some A-DNA sequences the minor-groove geometry and helix-axis curvature for this structure is compared with all others of the type d(GGXATXCC).