Specific zinc-finger architecture required for HIV-1 nucleocapsid protein's nucleic acid chaperone function.
The nucleocapsid protein (NC) of HIV type 1 (HIV-1) is a nucleic acid chaperone that facilitates the rearrangement of nucleic acid secondary structure during reverse transcription. HIV-1 NC contains two CCHC-type zinc binding domains. Here, we use optical tweezers to stretch single lambda-DNA molecules through the helix-to-coil transition in the presence of wild-type and several mutant forms of HIV-1 NC with altered zinc-finger domains. Although all forms of NC lowered the cooperativity of the DNA helix-coil transition, subtle changes in the zinc-finger structures reduced NC's effect on the transition. The change in cooperativity of the DNA helix-coil transition correlates strongly with in vitro nucleic acid chaperone activity measurements and in vivo HIV-1 replication studies using the same NC mutants. Moreover, Moloney murine leukemia virus NC, which contains a single zinc finger, had little effect on transition cooperativity. These results suggest that a specific two-zinc-finger architecture is required to destabilize nucleic acids for optimal chaperone activity during reverse transcription in complex retroviruses such as HIV-1.
Williams
Mark C
MC
Department of Physics and Center for Interdisciplinary Research on Complex Systems, Northeastern University, 111 Dana Research Center, Boston, MA 02115, USA. mark@neu.edu
Gorelick
Robert J
RJ
Musier-Forsyth
Karin
K
D000595:Amino Acid Sequence; D015497:HIV-1 / Q000502:physiology*; D018832:Molecular Chaperones / Q000737:chemistry / Q000502:physiology*; D008969:Molecular Sequence Data; D019590:Nucleocapsid Proteins / Q000737:chemistry / Q000502:physiology*; D014764:Viral Proteins / Q000737:chemistry / Q000502:physiology*; D016335:Zinc Fingers
D018832:Molecular Chaperones; D019590:Nucleocapsid Proteins; D014764:Viral Proteins