HIV-1 Nucleocapsid Protein Switches the Pathway of Transactivation Response Element RNA/DNA Annealing from Loop-Loop Kissing to Zipper

JOURNAL OF MOLECULAR BIOLOGY

卷:386

Article

Vo, My-Nuong^2,3  Barany, George^2,3  Rouzina, Ioulia¹  Musier-Forsyth, Karin^4,5 

[1] Univ Minnesota, Dept Biochem Mol Biol & Biophys, Minneapolis, MN 55455 USA

[2] Univ Minnesota, Dept Chem, Minneapolis, MN 55455 USA

[3] Univ Minnesota, Inst Mol Virol, Minneapolis, MN 55455 USA

[4] Ohio State Univ, Dept Chem, Columbus, OH 43210 USA

[5] Ohio State Univ, Dept Biochem, Columbus, OH 43210 USA

关键词: nucleic acid chaperone activity;    HIV-1 nucleocapsid protein;    TAR RNA/DNA annealing;    minus-strand transfer;    nucleic acid aggregation;   

DOI  :  10.1016/j.jmb.2008.12.070

来源: Elsevier

【 摘 要 】

The chaperone activity of HIV-1. (human immunodeficiency virus type 1) nucleocapsid protein (NC) facilitates multiple nucleic acid rearrangements that are critical for reverse transcription of the single-stranded RNA genome into double-stranded DNA. Annealing of the transactivation response element (TAR) RNA hairpin to a complementary TAR DNA hairpin is an essential step in the minus-strand transfer step of reverse transcription. Previously, we used truncated 27-nt mini-TAR RNA and DNA constructs to investigate this annealing reaction pathway in the presence and in the absence of HIV-1 NC. In this work, full-length 59-nt TAR RNA and TAR DNA constructs were used to systematically study TAR hairpin annealing kinetics. In the absence of NC, full-length TAR hairpin annealing is similar to 10-fold slower than mini-TAR annealing. Similar to mini-TAR annealing, the reaction pathway for TAR in the absence of NC involves the fast formation of an unstable kissing loop intermediate, followed by a slower conversion to an extended duplex. NC facilitates the annealing of TAR by similar to 10(5)-fold by stabilizing the bimolecular intermediate (similar to 10(4)-fold) and promoting the subsequent exchange reaction (similar to 10-fold). In contrast to the mini-TAR annealing pathway, wherein NC-mediated annealing can initiate through both loop-loop kissing and a distinct zipper pathway involving nucleation at the 3'-/5'-terminal ends, full-length TAR hairpin annealing switches predominantly to the zipper pathway in the presence of saturated NC. (c) 2009 Elsevier Ltd. All rights reserved.

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