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PDBsum entry 402d
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References listed in PDB file
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Key reference
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Title
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Structure of an RNA internal loop consisting of tandem c-A+ base pairs.
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Authors
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S.B.Jang,
L.W.Hung,
Y.I.Chi,
E.L.Holbrook,
R.J.Carter,
S.R.Holbrook.
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Ref.
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Biochemistry, 1998,
37,
11726-11731.
[DOI no: ]
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PubMed id
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Abstract
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The crystal structure of the RNA octamer 5'-CGC(CA)GCG-3' has been determined
from X-ray diffraction data to 2.3 A 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.
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Headers
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