Refinement of the solution structure of the RNA-DNA hybrid 5'-[r(GCA)d(TGC)]2. Combined use of nuclear magnetic resonance and restrained molecular dynamics.
The solution conformation of the self-complementary RNA-DNA hybrid hexamer 5'-[r(GCA)d(TGC)]2 is investigated by NMR spectroscopy and restrained molecular dynamics. The 1H-NMR spectrum is assigned in a sequential manner using two-dimensional homonuclear Hartmann-Hahn and nuclear Overhauser enhancement spectroscopy. From the latter a set of 178 approximate interproton distance restraints are determined and used as the basis of a structure refinement by restrained molecular dynamics. Eight independent calculations are carried out, four from a classical A-type geometry and four from a classical B-type one. Convergence is achieved to very similar A-type structures with an average atomic root mean square difference between them of 1.0 +/- 0.2 A. The converged structures exhibit variations in helical parameters similar to those found previously for the analogue RNA hexamer 5'-r(GCAUGC)2 [(1988) Biochemistry 27, 1735-1743].
Happ
C S
CS
Max-Planck Institut für Biochemie, Martinsried bei München, FRG.
Happ
E
E
Clore
G M
GM
Gronenborn
A M
AM
D004247:DNA; D009682:Magnetic Resonance Spectroscopy; D009690:Nucleic Acid Conformation; D009693:Nucleic Acid Hybridization; D011522:Protons; D012313:RNA; D012984:Software; D012996:Solutions
D011522:Protons; D012996:Solutions; D012313:RNA; D004247:DNA