title: Structure of the tetradecanucleotide d(CCCCGGTACCGGGG)2 as an A-DNA duplex.
abstract: The crystal structure of the tetradecanucleotide sequence d(CCCCGGTACCGGGG)(2) has been determined at 2.5 Å resolution in the tetragonal space group P4(1). This sequence was designed with the expectation of a four-way junction. However, the sequence crystallized as an A-DNA duplex and represents more than one full turn of the A-helix. The crystallographic asymmetric unit consists of one tetradecanucleotide duplex. The structural parameters of the A-type DNA duplex structure and the crystal-packing arrangement are described. One Mn(2+) ion was identified with direct coordination to the N7 position of G(13) and a water molecule at the major-groove side of the C(2)·G(13) base pair.
authors.affiliation: C. A. S. in Crystallography and Biophysics, University of Madras, Guindy, Chennai 600 025, India.
authors.forename: Pradeep Kumar
authors.initials: PK
authors.lastname: Mandal
authors.forename: Sarkarai
authors.initials: S
authors.lastname: Venkadesh
authors.forename: Namasivayam
authors.initials: N
authors.lastname: Gautham
mesh_terms: D044704:DNA, A-Form / Q000737:chemistry*; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D044704:DNA, A-Form; D009838:Oligodeoxyribonucleotides; D014867:Water