Egli M, Usman N, Rich A.
FASEB J. 1992 Jan 1; 6: A150.
Dept. of Biology, MIT, Cambridge, MA 02139.
In DNA replication, Okazaki fragments are formed as double stranded intermediates during synthesis of the lagging strand. They are composed of the growing DNA strand primed by RNA and the template strand. The DNA oligonucleotide d(GGGTATACGC) and the chimeric RNA-DNA oligonucleotide r(GCG)d(TATACCC) were combined to form a synthetic Okazaki fragment and its structure was determined by X-ray crystallography at 2 angstrom resolution. The fragment adopts an overall A-conformation with 11 residues per turn. Although the base pair geometry particularly in the central TATA part is distorted, there is no evidence for a transition between RNA-DNA hybrid and DNA duplex. The RNA trimer therefore locks the complete fragment in the A conformation. The conformation adopted by double-stranded RNA-DNA hybrids was studied by placing an RNA residue at specific sites within the self-complementary DNA sequence d(GCGTATACGC) and determining the crystal structures of the hybrids. Our results suggest that a single RNA residue per strand can drive the duplex into the A-conformation.
Publication Types:
Keywords:
- Base Pairing
- Base Sequence
- DNA
- DNA Replication
- Molecular Conformation
- Nucleic Acid Conformation
- Okazaki fragments
- Oligonucleotides
- RNA
- RNA-Directed DNA Polymerase
- X-Rays
- genetics
- radiography
- NASA Discipline Exobiology
- NASA Discipline Number 52-20
- NASA Program Exobiology
- Non-NASA Center
Other ID:
UI: 102212655
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