A retroviral RNA kissing complex containing only two G.C base pairs.
The dimerization of viral RNA through noncovalent interactions at their 5' ends is a key step in the life cycle of retroviruses. In Moloney murine leukemia virus, three stem-loops are important in this process. One is a self-complementary tetraloop (H1), but the other two stem-loops (H2, H3) contain highly conserved GACG tetraloops that are not self-complementary sequences. Using two-dimensional NMR, we determined the structure of the H3 stem-loop. Surprisingly, it forms a stable, homodimeric kissing complex through only two intermolecular G small middle dotC base pairs. Cross-strand interactions of the adenines adjacent to the intermolecular G small middle dotC base pairs, plus unusual strong electrostatic interactions around the base pairs, contribute to the unexpected stability. This structure shows how even stem-loops without self-complementary sequences can facilitate the intermolecular recognition between two identical RNAs, and thus initiate dimerization and encapsidation of retroviral RNAs.
Kim
C H
CH
Department of Chemistry, University of California, and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley 94720-1460, USA.
Tinoco
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D000225:Adenine / Q000378:metabolism; D020029:Base Pairing / Q000235:genetics* / Q000528:radiation effects; D001483:Base Sequence; D003596:Cytosine / Q000378:metabolism*; D019281:Dimerization; D006147:Guanine / Q000378:metabolism*; D008958:Models, Molecular; D008979:Moloney murine leukemia virus / Q000235:genetics*; D019906:Nuclear Magnetic Resonance, Biomolecular; D009691:Nucleic Acid Denaturation / Q000528:radiation effects; D020871:RNA Stability / Q000528:radiation effects; D012367:RNA, Viral / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D055672:Static Electricity; D013696:Temperature; D014466:Ultraviolet Rays
D012367:RNA, Viral; D006147:Guanine; D003596:Cytosine; D000225:Adenine