Search:
Computing and Library Services - delivering an inspiring information environment

Time-Resolved Fluorescence Investigation of the Human Immunodeficiency Virus Type 1 Nucleocapsid Protein: Influence of the Binding of Nucleic Acids

Bombarda, Elisa, Ababou, Abdessamad, Vuilleumier, Constance, Gerard, Dominique, Roques, Bernard P., Piemont, Etienne and Mely, Yves (1999) Time-Resolved Fluorescence Investigation of the Human Immunodeficiency Virus Type 1 Nucleocapsid Protein: Influence of the Binding of Nucleic Acids. Biophysical Journal, 76 (3). pp. 1561-1570. ISSN 0006-3495

[img]
Preview
PDF - Published Version
Download (134kB) | Preview

    Abstract

    Depending on the HIV-1 isolate, MN or BH10, the nucleocapsid protein, NCp7, corresponds to a 55- or 71-amino acid length product, respectively. The MN NCp7 contains a single Trp residue at position 37 in the distal zinc finger motif, and the BH10 NCp7 contains an additional Trp, at position 61 in the C-terminal chain. The time-resolved intensity decay parameters of the zinc-saturated BH10 NCp7 were determined and compared to those of single-Trp-containing derivatives. The fluorescence decay of BH10 NCp7 could be clearly represented as a linear combination (with respect to both lifetimes and fractional intensities) of the individual emitting Trp residues. This suggested the absence of interactions between the two Trp residues, a feature that was confirmed by molecular modeling and fluorescence energy transfer studies. In the presence of tRNAPhe, taken as a RNA model, the same conclusions hold true despite the large fluorescence decrease induced by the binding of tRNAPhe. Indeed, the fluorescence of Trp37 appears almost fully quenched, in keeping with a stacking of this residue with the bases of tRNAPhe. Despite the multiple binding sites in tRNAPhe, the large prevalence of ultrashort lifetimes, associated with the stacking of Trp37, suggests that this stacking constitutes a major feature in the binding process of NCp7 to nucleic acids. In contrast, Trp61 only stacked to a small extent with tRNAPhe. The behavior of this residue in the tRNAPhe-NCp7 complexes appeared to be rather heterogeneous, suggesting that it does not constitute a major determinant in the binding process. Finally, our data suggested that the binding of NCp7 proteins from the two HIV-1 strains to nonspecific nucleic acid sequences was largely similar.

    Item Type: Article
    Subjects: Q Science > Q Science (General)
    Q Science > QD Chemistry
    Schools: School of Applied Sciences
    Related URLs:
    Depositing User: Sara Taylor
    Date Deposited: 22 Apr 2010 09:46
    Last Modified: 28 Jul 2010 19:55
    URI: http://eprints.hud.ac.uk/id/eprint/7473

    Document Downloads

    Downloader Countries

    More statistics for this item...

    Item control for Repository Staff only:

    View Item

    University of Huddersfield, Queensgate, Huddersfield, HD1 3DH Copyright and Disclaimer All rights reserved ©