skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Crystal structure of an HIV assembly and maturation switch

Abstract

Virus assembly and maturation proceed through the programmed operation of molecular switches, which trigger both local and global structural rearrangements to produce infectious particles. HIV-1 contains an assembly and maturation switch that spans the C-terminal domain (CTD) of the capsid (CA) region and the first spacer peptide (SP1) of the precursor structural protein, Gag. The crystal structure of the CTD-SP1 Gag fragment is a goblet-shaped hexamer in which the cup comprises the CTD and an ensuing type II β-turn, and the stem comprises a 6-helix bundle. The β-turn is critical for immature virus assembly and the 6-helix bundle regulates proteolysis during maturation. This bipartite character explains why the SP1 spacer is a critical element of HIV-1 Gag but is not a universal property of retroviruses. Our results also indicate that HIV-1 maturation inhibitors suppress unfolding of the CA-SP1 junction and thereby delay access of the viral protease to its substrate.

Authors:
; ; ; ; ; ; ORCiD logo
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
National Institutes of Health (NIH)
OSTI Identifier:
1267471
Resource Type:
Journal Article
Resource Relation:
Journal Name: eLife; Journal Volume: 5; Journal Issue: 2016
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

Wagner, Jonathan M., Zadrozny, Kaneil K., Chrustowicz, Jakub, Purdy, Michael D., Yeager, Mark, Ganser-Pornillos, Barbie K., and Pornillos, Owen. Crystal structure of an HIV assembly and maturation switch. United States: N. p., 2016. Web. doi:10.7554/eLife.17063.
Wagner, Jonathan M., Zadrozny, Kaneil K., Chrustowicz, Jakub, Purdy, Michael D., Yeager, Mark, Ganser-Pornillos, Barbie K., & Pornillos, Owen. Crystal structure of an HIV assembly and maturation switch. United States. doi:10.7554/eLife.17063.
Wagner, Jonathan M., Zadrozny, Kaneil K., Chrustowicz, Jakub, Purdy, Michael D., Yeager, Mark, Ganser-Pornillos, Barbie K., and Pornillos, Owen. 2016. "Crystal structure of an HIV assembly and maturation switch". United States. doi:10.7554/eLife.17063.
@article{osti_1267471,
title = {Crystal structure of an HIV assembly and maturation switch},
author = {Wagner, Jonathan M. and Zadrozny, Kaneil K. and Chrustowicz, Jakub and Purdy, Michael D. and Yeager, Mark and Ganser-Pornillos, Barbie K. and Pornillos, Owen},
abstractNote = {Virus assembly and maturation proceed through the programmed operation of molecular switches, which trigger both local and global structural rearrangements to produce infectious particles. HIV-1 contains an assembly and maturation switch that spans the C-terminal domain (CTD) of the capsid (CA) region and the first spacer peptide (SP1) of the precursor structural protein, Gag. The crystal structure of the CTD-SP1 Gag fragment is a goblet-shaped hexamer in which the cup comprises the CTD and an ensuing type II β-turn, and the stem comprises a 6-helix bundle. The β-turn is critical for immature virus assembly and the 6-helix bundle regulates proteolysis during maturation. This bipartite character explains why the SP1 spacer is a critical element of HIV-1 Gag but is not a universal property of retroviruses. Our results also indicate that HIV-1 maturation inhibitors suppress unfolding of the CA-SP1 junction and thereby delay access of the viral protease to its substrate.},
doi = {10.7554/eLife.17063},
journal = {eLife},
number = 2016,
volume = 5,
place = {United States},
year = 2016,
month = 7
}
  • The 3 processing of most bacterial precursor tRNAs involves exonucleolytic trimming to yield a mature CCA end. This step is carried out by RNase T, a member of the large DEDD family of exonucleases. We report the crystal structures of RNase T from Escherichia coli and Pseudomonas aeruginosa, which show that this enzyme adopts an opposing dimeric arrangement, with the catalytic DEDD residues from one monomer closely juxtaposed with a large basic patch on the other monomer. This arrangement suggests that RNase T has to be dimeric for substrate specificity, and agrees very well with prior site-directed mutagenesis studies. Themore » dimeric architecture of RNase T is very similar to the arrangement seen in oligoribonuclease, another bacterial DEDD family exoribonuclease. The catalytic residues in these two enzymes are organized very similarly to the catalytic domain of the third DEDD family exoribonuclease in E. coli, RNase D, which is monomeric.« less
  • Bacteria switch the direction their flagella rotate to control movement. FliM, along with FliN and FliG, compose a complex in the motor that, upon binding phosphorylated CheY, reverses the sense of flagellar rotation. The 2.0- Angstroms resolution structure of the FliM middle domain (FliMM) from Thermotoga maritima reveals a pseudo-2-fold symmetric topology similar to the CheY phosphatases CheC and CheX. A variable structural element, which, in CheC, mediates binding to CheD ({alpha}2') and, in CheX, mediates dimerization ({beta}x), has a truncated structure unique to FliM ({alpha}2'). An exposed helix of FliMM ({alpha}1) does not contain the catalytic residues of CheCmore » and CheX but does include positions conserved in FliM sequences. Cross-linking experiments with site-directed cysteine mutants show that FliM self-associates through residues on {alpha}1 and {alpha}2'. CheY activated by BeF3- binds to FliM with {approx}40-fold higher affinity than CheY (Kd = 0.04 {micro}M vs. 2 {micro}M). Mapping residue conservation, suppressor mutation sites, binding data, and deletion analysis onto the FliMM surface defines regions important for contacts with the stator-interacting protein FliG and for either counterclockwise or clockwise rotation. Association of 33-35 FliM subunits would generate a 44- to 45-nm-diameter disk, consistent with the known dimensions of the C-ring. The localization of counterclockwise- and clockwise-biasing mutations to distinct surfaces suggests that the binding of phosphorylated CheY cooperatively realigns FliM around the ring.« less
  • No abstract prepared.