The high-resolution crystal structure of a parallel-stranded guanine tetraplex.
Repeat tracts of guanine bases found in DNA and RNA can form tetraplex structures in the presence of a variety of monovalent cations. Evidence suggests that guanine tetraplexes assume important functions within chromosomal telomeres, immunoglobulin switch regions, and the human immunodeficiency virus genome. The structure of a parallel-stranded tetraplex formed by the hexanucleotide d(TG4T) and stabilized by sodium cations was determined by x-ray crystallography to 1.2 angstroms resolution. Sharply resolved sodium cations were found between and within planes of hydrogen-bonded guanine quartets, and an ordered groove hydration was observed. Distinct intra- and intermolecular stacking arrangements were adopted by the guanine quartets. Thymine bases were exclusively involved in making extensive lattice contacts.
Laughlan
G
G
Medical Research Council Virology Unit, University of Glasgow, UK.
Murchie
A I
AI
Norman
D G
DG
Moore
M H
MH
Moody
P C
PC
Lilley
D M
DM
Luisi
B
B
D003196:Computer Graphics; D003460:Crystallization; D018360:Crystallography, X-Ray; D006147:Guanine / Q000737:chemistry*; D006860:Hydrogen Bonding; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D012964:Sodium
D009838:Oligodeoxyribonucleotides; D006147:Guanine; D012964:Sodium