| Autor: |
van Knippenberg PH; Department of Biochemistry, Gorlaeus Laboratories, University of Leiden, The Netherlands., Formenoy LJ, Heus HA |
| Jazyk: |
angličtina |
| Zdroj: |
Biochimica et biophysica acta [Biochim Biophys Acta] 1990 Aug 27; Vol. 1050 (1-3), pp. 14-7. |
| DOI: |
10.1016/0167-4781(90)90134-n |
| Abstrakt: |
U.G basepairs are well-established elements of RNA structure. The geometry of this pair is different, however, from classical Watson-Crick basepairs. This leads to an unusual stacking of the basepair: overlap with the basepair at the 5' side of the U (and the 3' side of the G) is strong (stacked) while it is weak with the basepair on the other side (destacked). The closure of an RNA helix by a U.G pair will be energetically unfavourable when the U residue occupies the 5' end. In transfer RNA there is a strong selection against a 'destacked' U.G pair at helix ends. In the 16S rRNA model of Escherichia coli there are 72 U.G pairs of which 36 or 22 occupy a helix end, depending on how such an end is defined. There is a slight preference for 'stacked' U.G's in these positions. It is remarkable, however, that of 13 very conserved U.G pairs in the 16S (-like) rRNA, 7 occur at helix ends and that 5 of these have the 'destacked' configuration. It is suggested that these pairs, if they exist at all in a hydrogen-bounded form, are stabilized by co-axial stacking with other helices or by interaction with a protein. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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