PDBsum entry 1x9v

Viral protein

PDB id: 1x9v

Contents

Protein chains

45 a.a. *

* Residue conservation analysis

PDB id:

1x9v

Name:

Viral protein

Title:

Dimeric structure of thE C-terminal domain of vpr

Structure:

Vpr protein. Chain: a, b. Fragment: c-terminal domain (residues 52-96). Synonym: viral protein r. Engineered: yes

Source:

Synthetic: yes. Other_details: the peptide was chemically synthesized by solid phase. The sequence of the peptide is found in human immunodeficiency virus type 1 (HIV-1)

NMR struc:

10 models

Authors:

S.Bourbigot,H.Beltz,J.Denis,N.Morellet,B.P.Roques,Y.Mely,S.Bouaziz

Key ref:

S.Bourbigot et al. (2005). The C-terminal domain of the HIV-1 regulatory protein Vpr adopts an antiparallel dimeric structure in solution via its leucine-zipper-like domain. Biochem J, 387, 333-341. PubMed id: 15571493

Date:

24-Aug-04 Release date: 14-Jun-05

Protein chains

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.?

Biochem J 387:333-341 (2005)

PubMed id: 15571493

The C-terminal domain of the HIV-1 regulatory protein Vpr adopts an antiparallel dimeric structure in solution via its leucine-zipper-like domain.

S.Bourbigot, H.Beltz, J.Denis, N.Morellet, B.P.Roques, Y.Mély, S.Bouaziz.

ABSTRACT

HIV-1 Vpr is a highly conserved accessory protein that is involved in many functions of the virus life cycle. Vpr facilitates the entry of the HIV pre-integration complex through the nuclear pore, induces G2 cell cycle arrest, regulates cell apoptosis, increases transcription from the long terminal repeat and enhances viral replication. Vpr contains a Leu/Ile-rich domain (amino acids 60-81) in its C-terminal part, which is critical for dimerization. The sequence comprising residues 52-96 is implicated in properties of the protein such as DNA interaction and apoptosis via interaction with the adenine nucleotide translocator. To understand the specific interactions of Vpr-(52-96), the ability of this peptide to dimerize via a leucine-zipper mechanism has been investigated, by NMR and fluorescence spectroscopy. In contrast with results from a study performed in the presence of trifluoroethanol, our results, obtained in 30% (v/v) [2H]acetonitrile, show that Vpr-(52-96) in solution still forms an a-helix spanning residues 53-75, but dimerizes in an antiparallel orientation, through hydrophobic interactions between leucine and isoleucine residues and stacking between His71 and Trp54. Moreover, to demonstrate the physiological relevance of the dimer structure, fluorescence spectroscopy experiments have been performed in a Mes buffer, which confirmed the formation of the dimer in aqueous solution and highlighted the spatial proximity between Trp54 and His71. Surprisingly, the leucine-zipper structure shown in the present work for Vpr-(52-96) mimics the structure of full-length Vpr-(1-96), and this could explain why some of the properties of Vpr-(52-96) and Vpr-(1-96) are identical, while some are even enhanced for Vpr-(52-96), particularly in the case of DNA transfection experiments.