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Title: Glycine Substitution at Helix-to-Coil Transitions Facilitates the Structural Determination of a Stabilized Subtype C HIV Envelope Glycoprotein

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
OTHER
OSTI Identifier:
1368277
Resource Type:
Journal Article
Resource Relation:
Journal Name: Immunity; Journal Volume: 46; Journal Issue: 5
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

Guenaga, Javier, Garces, Fernando, de Val, Natalia, Stanfield, Robyn L., Dubrovskaya, Viktoriya, Higgins, Brett, Carrette, Barbara, Ward, Andrew B., Wilson, Ian A., and Wyatt, Richard T. Glycine Substitution at Helix-to-Coil Transitions Facilitates the Structural Determination of a Stabilized Subtype C HIV Envelope Glycoprotein. United States: N. p., 2017. Web. doi:10.1016/j.immuni.2017.04.014.
Guenaga, Javier, Garces, Fernando, de Val, Natalia, Stanfield, Robyn L., Dubrovskaya, Viktoriya, Higgins, Brett, Carrette, Barbara, Ward, Andrew B., Wilson, Ian A., & Wyatt, Richard T. Glycine Substitution at Helix-to-Coil Transitions Facilitates the Structural Determination of a Stabilized Subtype C HIV Envelope Glycoprotein. United States. doi:10.1016/j.immuni.2017.04.014.
Guenaga, Javier, Garces, Fernando, de Val, Natalia, Stanfield, Robyn L., Dubrovskaya, Viktoriya, Higgins, Brett, Carrette, Barbara, Ward, Andrew B., Wilson, Ian A., and Wyatt, Richard T. 2017. "Glycine Substitution at Helix-to-Coil Transitions Facilitates the Structural Determination of a Stabilized Subtype C HIV Envelope Glycoprotein". United States. doi:10.1016/j.immuni.2017.04.014.
@article{osti_1368277,
title = {Glycine Substitution at Helix-to-Coil Transitions Facilitates the Structural Determination of a Stabilized Subtype C HIV Envelope Glycoprotein},
author = {Guenaga, Javier and Garces, Fernando and de Val, Natalia and Stanfield, Robyn L. and Dubrovskaya, Viktoriya and Higgins, Brett and Carrette, Barbara and Ward, Andrew B. and Wilson, Ian A. and Wyatt, Richard T.},
abstractNote = {},
doi = {10.1016/j.immuni.2017.04.014},
journal = {Immunity},
number = 5,
volume = 46,
place = {United States},
year = 2017,
month = 5
}
  • Functional studies of HIV-1 envelope glycoproteins (Envs) commonly include the generation of pseudoviruses, which are produced by co-transfection of rev-vpu-env cassettes with an env-deficient provirus. Here, we describe six Env constructs from transmitted/founder HIV-1 that were defective in the pseudotyping assay, although two produced infectious virions when expressed from their cognate proviruses. All of these constructs exhibited an unusual gene arrangement in which the first exon of rev (rev1) and vpu were in the same reading frame without an intervening stop codon. Disruption of the rev1-vpu fusion gene by frameshift mutation, stop codon, or abrogation of the rev initiation codonmore » restored pseudovirion infectivity. Introduction of the fusion gene into wildtype Env cassettes severely compromised their function. The defect was not due to altered env and rev transcription or a dominant negative effect of the expressed fusion protein, but seemed to be caused by inefficient translation at the env initiation codon. Although the rev1-vpu polymorphism affects Env expression only in vitro, it can cause problems in studies requiring Env complementation, such as analyses of co-receptor usage and neutralization properties, since 3% of subtype A, 20% of subtype C and 5% of CRF01{sub A}/E viruses encode the fusion gene. A solution is to eliminate the rev initiation codon when amplifying rev-vpu-env cassettes since this increases Env expression irrespective of the presence of the polymorphism.« less
  • The human immunodeficiency virus (HIV-1) transmembrane envelope glycoprotein, gp41, which mediates virus-cell fusion, exists in at least three different conformations within the trimeric envelope glycoprotein complex. The structures of the prefusogenic and intermediate states are unknown; structures representing the postfusion state have been solved. In the postfusion conformation, three helical heptad repeat 2 (HR2) regions pack in an antiparallel fashion into the hydrophobic grooves on the surface of a triple-helical coiled coil formed by the heptad repeat 1 (HR1) regions. We studied the prefusogenic conformation of gp41 by mutagenic alteration of membrane-anchored and soluble forms of the HIV-1 envelope glycoproteins.more » Our results indicate that, in the HIV-1 envelope glycoprotein precursor, the gp41 HR1 region is in a conformation distinct from that of a trimeric coiled coil. Thus, the central gp41 coiled coil is formed during the transition of the HIV-1 envelope glycoproteins from the precursor state to the receptor-bound intermediate.« less
  • Thermodynamics of helix-coil transitions in amino acid homo-oligomers are studied by the recently proposed multicanonical algorithms. Homo-oligomers of length 10 are considered for three characteristic amino acids, alanine (helix former), valine (helix indifferent), and glycine (helix breaker). For alanine other lengths (15 and 20) are also considered in order to examine the length dependence. From one multicanonical production run with completely random initial conformations, we have obtained the lowest-energy conformations and various thermodynamic quantities (average helicity, Zimm-Bragg s and {sigma} parameters, free energy differences between helix and coil states, etc.) as functions of temperature. The results confirm the fact thatmore » alanine is helix-forming, valine is helix-indifferent, and glycine is helix-breaking. 36 refs., 10 figs., 5 tabs.« less