Abstract
The crystal structure of the RNA octamer 5'-CGC(CA)GCG-3' has been determined from X-ray diffraction data to 2.3 Å resolution. In the crystal, this oligomer forms a self-complementary double helix in the asymmetric unit. Tandem non-Watson-Crick C-A and A-C base pairs comprise an internal loop in the middle of the duplex, which is incorporated with little distortion of the A-form double helix. From the geometry of the C-A base pairs, it is inferred that the adenosine imino group is protonated and donates a hydrogen bond to the carbonyl group of the cytosine. The wobble geometry of the C-A+ base pairs is very similar to that of the common U-G non-Watson-Crick pair.
Original language | English (US) |
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Pages (from-to) | 11726-11731 |
Number of pages | 6 |
Journal | Biochemistry |
Volume | 37 |
Issue number | 34 |
DOIs | |
State | Published - Aug 25 1998 |