scholarly journals Cryo-EM structures and atomic model of the HIV-1 strand transfer complex intasome

Science ◽  
2017 ◽  
Vol 355 (6320) ◽  
pp. 89-92 ◽  
Author(s):  
Dario Oliveira Passos ◽  
Min Li ◽  
Renbin Yang ◽  
Stephanie V. Rebensburg ◽  
Rodolfo Ghirlando ◽  
...  
Keyword(s):  
High Resolution ◽  
Higher Order ◽  
Strand Transfer ◽  
Structural Studies ◽  
Cryo Electron Microscopy ◽  
Target Dna ◽  
Carboxyl Terminal ◽  
Host Target ◽  
Hiv 1 ◽  
Host Chromatin

Like all retroviruses, HIV-1 irreversibly inserts a viral DNA (vDNA) copy of its RNA genome into host target DNA (tDNA). The intasome, a higher-order nucleoprotein complex composed of viral integrase (IN) and the ends of linear vDNA, mediates integration. Productive integration into host chromatin results in the formation of the strand transfer complex (STC) containing catalytically joined vDNA and tDNA. HIV-1 intasomes have been refractory to high-resolution structural studies. We used a soluble IN fusion protein to facilitate structural studies, through which we present a high-resolution cryo–electron microscopy (cryo-EM) structure of the core tetrameric HIV-1 STC and a higher-order form that adopts carboxyl-terminal domain rearrangements. The distinct STC structures highlight how HIV-1 can use the common retroviral intasome core architecture to accommodate different IN domain modules for assembly.

scholarly journals Structural basis for strand-transfer inhibitor binding to HIV intasomes

Science ◽  
2020 ◽  
Vol 367 (6479) ◽  
pp. 810-814 ◽  
Author(s):  
Dario Oliveira Passos ◽  
Min Li ◽  
Ilona K. Jóźwik ◽  
Xue Zhi Zhao ◽  
Diogo Santos-Martins ◽  
...  
Keyword(s):  
High Resolution ◽  
Drug Target ◽  
Antiretroviral Drugs ◽  
Drug Binding ◽  
Structural Basis ◽  
Strand Transfer ◽  
Cryo Electron Microscopy ◽  
Integrase Strand Transfer Inhibitors ◽  
Transfer Inhibitor ◽  
Host Chromatin

The HIV intasome is a large nucleoprotein assembly that mediates the integration of a DNA copy of the viral genome into host chromatin. Intasomes are targeted by the latest generation of antiretroviral drugs, integrase strand-transfer inhibitors (INSTIs). Challenges associated with lentiviral intasome biochemistry have hindered high-resolution structural studies of how INSTIs bind to their native drug target. Here, we present high-resolution cryo–electron microscopy structures of HIV intasomes bound to the latest generation of INSTIs. These structures highlight how small changes in the integrase active site can have notable implications for drug binding and design and provide mechanistic insights into why a leading INSTI retains efficacy against a broad spectrum of drug-resistant variants. The data have implications for expanding effective treatments available for HIV-infected individuals.

scholarly journals Inhibition of Human Immunodeficiency Virus Type 1 Concerted Integration by Strand Transfer Inhibitors Which Recognize a Transient Structural Intermediate

2007 ◽  
Vol 81 (22) ◽  
pp. 12189-12199 ◽  
Author(s):  
Krishan K. Pandey ◽  
Sibes Bera ◽  
Jacob Zahm ◽  
Ajaykumar Vora ◽  
Kara Stillmock ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Dependent Manner ◽  
Strand Transfer ◽  
Viral Dna ◽  
Target Dna ◽  
Immunodeficiency Virus ◽  
Dna Ends ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) integrase (IN) inserts the viral DNA genome into host chromosomes. Here, by native agarose gel electrophoresis, using recombinant IN with a blunt-ended viral DNA substrate, we identified the synaptic complex (SC), a transient early intermediate in the integration pathway. The SC consists of two donor ends juxtaposed by IN noncovalently. The DNA ends within the SC were minimally processed (∼15%). In a time-dependent manner, the SC associated with target DNA and progressed to the strand transfer complex (STC), the nucleoprotein product of concerted integration. In the STC, the two viral DNA ends are covalently attached to target and remain associated with IN. The diketo acid inhibitors and their analogs effectively inhibit HIV-1 replication by preventing integration in vivo. Strand transfer inhibitors L-870,810, L-870,812, and L-841,411, at low nM concentrations, effectively inhibited the concerted integration of viral DNA donor in vitro. The inhibitors, in a concentration-dependent manner, bound to IN within the SC and thereby blocked the docking onto target DNA, which thus prevented the formation of the STC. Although 3′-OH recessed donor efficiently formed the STC, reactions proceeding with this substrate exhibited marked resistance to the presence of inhibitor, requiring significantly higher concentrations for effective inhibition of all strand transfer products. These results suggest that binding of inhibitor to the SC occurs prior to, during, or immediately after 3′-OH processing. It follows that the IN-viral DNA complex is “trapped” by the strand transfer inhibitors via a transient intermediate within the cytoplasmic preintegration complex.

scholarly journals A supramolecular assembly mediates lentiviral DNA integration

Science ◽  
2017 ◽  
Vol 355 (6320) ◽  
pp. 93-95 ◽  
Author(s):  
Allison Ballandras-Colas ◽  
Daniel P. Maskell ◽  
Erik Serrao ◽  
Julia Locke ◽  
Paolo Swuec ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Supramolecular Assembly ◽  
Structural Data ◽  
Higher Order ◽  
Viral Dna ◽  
Dna Integration ◽  
Cryo Electron Microscopy ◽  
Nucleoprotein Complex ◽  
Retroviral Integrase ◽  
Hiv 1

Retroviral integrase (IN) functions within the intasome nucleoprotein complex to catalyze insertion of viral DNA into cellular chromatin. Using cryo–electron microscopy, we now visualize the functional maedi-visna lentivirus intasome at 4.9 angstrom resolution. The intasome comprises a homo-hexadecamer of IN with a tetramer-of-tetramers architecture featuring eight structurally distinct types of IN protomers supporting two catalytically competent subunits. The conserved intasomal core, previously observed in simpler retroviral systems, is formed between two IN tetramers, with a pair of C-terminal domains from flanking tetramers completing the synaptic interface. Our results explain how HIV-1 IN, which self-associates into higher-order multimers, can form a functional intasome, reconcile the bulk of early HIV-1 IN biochemical and structural data, and provide a lentiviral platform for design of HIV-1 IN inhibitors.

scholarly journals HIV-1 integrase inhibitors that compete with the target DNA substrate define a unique strand transfer conformation for integrase

2000 ◽  
Vol 97 (21) ◽  
pp. 11244-11249 ◽  
Author(s):  
A. S. Espeseth ◽  
P. Felock ◽  
A. Wolfe ◽  
M. Witmer ◽  
J. Grobler ◽  
...  
Keyword(s):  
Strand Transfer ◽  
Integrase Inhibitors ◽  
Target Dna ◽  
Dna Substrate ◽  
Hiv 1

Computer processing of high-resolution images of periodic specimens

1986 ◽  
Vol 44 ◽  
pp. 2-5
Author(s):  
W. Chiu ◽  
M.F. Schmid ◽  
T.-W. Jeng
Keyword(s):  
High Resolution ◽  
Fourier Transforms ◽  
Complex Structure ◽  
Distribution Functions ◽  
Multiple Image ◽  
Cryo Electron Microscopy ◽  
Structure Factors ◽  
Unit Cells ◽  
High Resolution Images ◽  
Phase Probability Distribution

Cryo-electron microscopy has been developed to the point where one can image thin protein crystals to 3.5 Å resolution. In our study of the crotoxin complex crystal, we can confirm this structural resolution from optical diffractograms of the low dose images. To retrieve high resolution phases from images, we have to include as many unit cells as possible in order to detect the weak signals in the Fourier transforms of the image. Hayward and Stroud proposed to superimpose multiple image areas by combining phase probability distribution functions for each reflection. The reliability of their phase determination was evaluated in terms of a crystallographic “figure of merit”. Grant and co-workers used a different procedure to enhance the signals from multiple image areas by vector summation of the complex structure factors in reciprocal space.

scholarly journals Impact of long-term antiretroviral therapy on gut and oral microbiotas in HIV-1-infected patients

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mayumi Imahashi ◽  
Hirotaka Ode ◽  
Ayumi Kobayashi ◽  
Michiko Nemoto ◽  
Masakazu Matsuda ◽  
...  
Keyword(s):  
Antiretroviral Therapy ◽  
Reverse Transcriptase ◽  
Transcriptase Inhibitor ◽  
Strand Transfer ◽  
Intestinal Dysbiosis ◽  
Α Diversity ◽  
Reverse Transcriptase Inhibitor ◽  
Hiv 1 ◽  
Over Time

AbstractIn HIV-1-infected patients, antiretroviral therapy (ART) is a key factor that may impact commensal microbiota and cause the emergence of side effects. However, it is not fully understood how long-term ART regimens have diverse impacts on the microbial compositions over time. Here, we performed 16S ribosomal RNA gene sequencing of the fecal and salivary microbiomes in patients under different long-term ART. We found that ART, especially conventional nucleotide/nucleoside reverse transcriptase inhibitor (NRTI)-based ART, has remarkable impacts on fecal microbial diversity: decreased α-diversity and increased ß-diversity over time. In contrast, dynamic diversity changes in the salivary microbiome were not observed. Comparative analysis of bacterial genus compositions showed a propensity for Prevotella-enriched and Bacteroides-poor gut microbiotas in patients with ART over time. In addition, we observed a gradual reduction in Bacteroides but drastic increases in Succinivibrio and/or Megasphaera under conventional ART. These results suggest that ART, especially NRTI-based ART, has more suppressive impacts on microbiota composition and diversity in the gut than in the mouth, which potentially causes intestinal dysbiosis in patients. Therefore, NRTI-sparing ART, especially integrase strand transfer inhibitor (INSTI)- and/or non-nucleotide reverse transcriptase inhibitor (NNRTI)-containing regimens, might alleviate the burden of intestinal dysbiosis in HIV-1-infected patients under long-term ART.

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