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HELICAL STRUCTURE OF POLYPEPTIDES FROM THE C-TERMINAL HALF OF HIV-1 VPR, NMR, 20 STRUCTURES

Overview

Vpr, one of the accessory gene products encoded by HIV-1, is a 96-residue, protein with a number of functions, including targeting of the viral, pre-integration complex to the nucleus and inducing growth arrest of, dividing cells. We have characterized by 2D NMR the solution conformations, of bioactive synthetic peptide fragments of Vpr encompassing a pair of, H(F/S)RIG sequence motifs (residues 71-75 and 78-82 of HIV-1 Vpr) that, cause cell membrane permeabilization and death in yeast and mammalian, cells. Due to limited solubility of the peptides in water, their, structures were studied in aqueous trifluoroethanol. Peptide Vpr59-86, (residues 59-86 of Vpr) formed an alpha-helix encompassing residues 60-77, with a kink in the vicinity of residue 62. The first of the repeated, sequence motifs (HFRIG) participated in the well-defined alpha-helical, domain whereas the second (HSRIG) lay outside the helical domain and, formed a reverse turn followed by a less ordered region. On the other, hand, peptides Vpr71-82 and Vpr71-96, in which the sequence motifs were, located at the N-terminus, were largely unstructured under similar, conditions, as judged by their C(alpha)H chemical shifts. Thus, the HFRIG, and HSRIG motifs adopt alpha-helical and turn structures, respectively, when preceded by a helical structure, but are largely unstructured in, isolation. The implications of these findings for interpretation of the, structure-function relationships of synthetic peptides containing these, motifs are discussed.

About this Structure

1BDE is a Single protein structure of sequence from [1] with ACE and NH2 as ligands. Full crystallographic information is available from OCA.

Reference

Solution structure of peptides from HIV-1 Vpr protein that cause membrane permeabilization and growth arrest., Yao S, Torres AM, Azad AA, Macreadie IG, Norton RS, J Pept Sci. 1998 Nov;4(7):426-35. PMID:9851370

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