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.
Department of Chemistry, University of California, and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley 94720-1460, USA.
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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