Structure of a parallel-stranded tetramer of the Oxytricha telomeric DNA sequence dT4G4.
We report here the determination of the solution structure of the single-copy tetramer of the sequence dT4G4, the unit repeat in telomeres of the ciliated protozoan Oxytricha, in the presence of potassium ions. This is accomplished by a combination of sequential assignments and distance determinations from 2D proton NMR with model building, based on conformational analysis of the structure using a full-matrix NOESY simulation and molecular dynamics. Each strand in this tetramer structure has an identical environment and conformation: a parallel-stranded, right-handed helix, with all nucleotides in the C2'-endo, anti configuration. The T flanking the G cluster stacks in a 4-fold symmetrical helical array, while the remaining T's become increasingly flexible and sample multiple stacked configurations.
Los Alamos National Laboratory, Group T-10, New Mexico 87545.
G
G
Gupta
A E
AE
Garcia
Q
Q
Guo
M
M
Lu
N R
NR
Kallenbach
D000818:Animals; D016054:DNA, Protozoan / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D016813:Oxytricha / Q000737:chemistry*; D011522:Protons; D016615:Telomere
D016054:DNA, Protozoan; D009838:Oligodeoxyribonucleotides; D011522:Protons