PDBsum entry 1vpc

Regulatory protein

PDB id: 1vpc

Contents

Protein chain

45 a.a. *

* Residue conservation analysis

PDB id:

1vpc

Name:

Regulatory protein

Title:

C-terminal domain (52-96) of the HIV-1 regulatory protein vpr, nmr, 1 structure

Structure:

Vpr protein. Chain: a. Fragment: c-terminal domain, residues 52-96. Synonym: vpr HIV-1 (lai). Engineered: yes

Source:

Human immunodeficiency virus 1. Organism_taxid: 11676

NMR struc:

1 models

Authors:

W.Schueler,H.De Rocquigny,Y.Baudat,J.Sire,B.P.Roques

Key ref:

W.Schüler et al. (1999). NMR structure of the (52-96) C-terminal domain of the HIV-1 regulatory protein Vpr: molecular insights into its biological functions. J Mol Biol, 285, 2105-2117. PubMed id: 9925788 DOI: 10.1006/jmbi.1998.2381

Date:

20-Feb-98 Release date: 23-Mar-99

Protein chain

Q73369  (VPR_HV1B9) -  Protein Vpr from Human immunodeficiency virus type 1 group M subtype B (strain 89.6)

Seq: 96 a.a.

Struc: 45 a.a.

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1006/jmbi.1998.2381

J Mol Biol 285:2105-2117 (1999)

PubMed id: 9925788

NMR structure of the (52-96) C-terminal domain of the HIV-1 regulatory protein Vpr: molecular insights into its biological functions.

W.Schüler, K.Wecker, H.de Rocquigny, Y.Baudat, J.Sire, B.P.Roques.

ABSTRACT

The HIV-1 regulatory protein Vpr (96 amino acid residues) is incorporated into the virus particle through a mechanism involving its interaction with the C-terminal portion of Gag. Vpr potentiates virus replication by interrupting cell division in the G2 phase and participates in the nuclear transport of proviral DNA. The domain encompassing the 40 C-terminal residues of Vpr was shown to be involved in cell cycle arrest and binding of nucleocapsid protein NCp7, and suggested to promote nuclear provirus transfer. Accordingly, we show here that the synthetic 52-96 but not 1-51 sequences of Vpr interact with HIV-1 RNA. Based on these results, the structure of (52-96)Vpr was analysed by two-dimensional 1H-NMR in aqueous TFE (30%) solution and refined by restrained molecular dynamics. The structure is characterized by a long (53-78) amphipathic alpha-helix, followed by a less defined (79-96) C-terminal domain. The Leu60 and Leu67 side-chains are located on the hydrophobic side of the helix, suggesting their involvement in Vpr dimerization through a leucine zipper-type mechanism. Accordingly, their replacement by Ala eliminates Vpr dimerization in the two hybrid systems, while mutations of Ile74 and Ile81 have no effect. This was confirmed by gel filtration measurements and circular dichroism, which also showed that the alpha-helix still exists in (52-96)Vpr and its Ala60, Ala67 mutant in the presence and absence of TFE. Based on these results, a model of the coiled-coil Vpr dimer has been described, and its biological relevance as well as that of the structural characteristics of the 52-96 domain for the different functions of Vpr, including HIV-1 RNA binding, are discussed.

Selected figure(s)

Figure 4.
Figure 4. Superpositions of the final set of 15 refined (52-96)Vpr structures with respect to the back- bone atoms (N, C a , C0,O). Top, the entire 52-96 peptide ; bottom, resi- dues 54-73 corresponding with the helical region.

Figure 7.
Figure 7. Helical wheel representation of the helix 53- 78 in (52-96)Vpr illustrating the leucine zipper-like monodimeric interaction. The scheme displays residues 53 to 81. The hydrophobic residues are found in pos- itions d, a, g and e, showing the amphiphilic nature of the helix. A second identical (52-96)Vpr helix (grey) could contact the first one with the hydrophobic resi- dues in a and d positions in a homodimer.

The above figures are reprinted by permission from Elsevier: J Mol Biol (1999, 285, 2105-2117) copyright 1999.

Figures were selected by an automated process.