Structure of an RNA internal loop consisting of tandem C-A+ base pairs
Structure of an RNA internal loop consisting of tandem C-A+ base pairs
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DOI：
10.1021/bi980758j
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发表时间：
1998-08-25
期刊：
影响因子：
2.9
通讯作者：
Holbrook, SR
中科院分区：
文献类型：
--
作者：
Jang, SB;Hung, LW;Holbrook, SR
RNA八聚体5 ′-CGC（CA）GCG-3 ′的晶体结构已由X-射线衍射数据确定到2.3埃分辨率。在晶体中，这种低聚物在不对称单元中形成自互补双螺旋。串联的非沃森-克里克C-A和A-C碱基对在双链体的中间包含内环，其以A型双螺旋的小扭曲并入。从C-A碱基对的几何形状推断，腺苷亚氨基被质子化并与胞嘧啶的羰基形成氢键。C-A（+）碱基对的摆动几何形状与常见的U-G非沃森-克里克对非常相似。
The crystal structure of the RNA octamer 5'-CGC(CA)GCG-3' has been determined from X-ray diffraction data to 2.3 Angstrom 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.