Kinetics Study on the HIV-1 Ectodomain Protein Quaternary Structure Formation Reveals Coupling of Chain Folding and Self-Assembly in the Refolding Cascade

2014 ◽  
Vol 118 (45) ◽  
pp. 12827-12836
Author(s):  
Shu-Fang Cheng ◽  
Tai-Ching Sung ◽  
Chung-Chieh Chang ◽  
Mei-Ju Chou ◽  
Yun-Wei Chiang ◽  
...  
Keyword(s):  
Structure Formation ◽  
Self Assembly ◽  
Quaternary Structure ◽  
Kinetics Study ◽  
Chain Folding ◽  
Hiv 1

scholarly journals HIV-1 Matrix Protein p17 Promotes Lymphangiogenesis and Activates the Endothelin-1/Endothelin B Receptor Axis

2014 ◽  
Vol 34 (4) ◽  
pp. 846-856 ◽  
Author(s):  
Francesca Caccuri ◽  
Christine Rueckert ◽  
Cinzia Giagulli ◽  
Kai Schulze ◽  
Daniele Basta ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Lymph Node ◽  
Structure Formation ◽  
Highly Active Antiretroviral Therapy ◽  
Matrix Protein ◽  
Lymphatic Endothelial Cells ◽  
Endothelin 1 ◽  
Tumor Dissemination ◽  
Hiv 1

Objective— AIDS-related lymphomas are high grade and aggressively metastatic with poor prognosis. Lymphangiogenesis is essential in supporting proliferation and survival of lymphoma, as well as tumor dissemination. Data suggest that aberrant lymphangiogenesis relies on action of HIV-1 proteins rather than on a direct effect of the virus itself. HIV-1 matrix protein p17 was found to accumulate and persist in lymph nodes of patients even under highly active antiretroviral therapy. Because p17 was recently found to exert a potent proangiogenic activity by interacting with chemokine (C-X-C motif) receptors 1 and 2, we tested the prolymphangiogenic activity of the viral protein. Approach and Results— Human primary lymph node–derived lymphatic endothelial cells were used to perform capillary-like structure formation, wound healing, spheroids, and Western blot assays after stimulation with or without p17. Here, we show that p17 promotes lymphangiogenesis by binding to chemokine (C-X-C motif) receptor-1 and chemokine (C-X-C motif) receptor-2 expressed on lymph node–derived lymphatic endothelial cells and activating the Akt/extracellular signal–regulated kinase signaling pathway. In particular, it was found to induce capillary-like structure formation, sprout formation from spheroids, and increase lymph node–derived lymphatic endothelial cells motility. The p17 lymphangiogenic activity was, in part, sustained by activation of the endothelin-1/endothelin receptor B axis. A Matrigel plug assay showed that p17 was able to promote the outgrowth of lymphatic vessels in vivo, demonstrating that p17 directly regulates lymphatic vessel formation. Conclusions— Our results suggest that p17 may generate a prolymphangiogenic microenvironment and plays a role in predisposing the lymph node to lymphoma growth and metastasis. This finding offers new opportunities to identify treatment strategies in combating AIDS-related lymphomas.

scholarly journals The HIV-1 Nucleocapsid Regulates Its Own Condensation by Phase-Separated Activity-Enhancing Sequestration of the Viral Protease during Maturation

Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2312
Author(s):  
Sébastien Lyonnais ◽  
S. Kashif Sadiq ◽  
Cristina Lorca-Oró ◽  
Laure Dufau ◽  
Sara Nieto-Marquez ◽  
...  
Keyword(s):  
Self Assembly ◽  
Rna Binding ◽  
Weak Interactions ◽  
Biological Functions ◽  
Viral Protease ◽  
Virus Maturation ◽  
Sequential Processing ◽  
Rnp Granules ◽  
Crowded Environments ◽  
Hiv 1

A growing number of studies indicate that mRNAs and long ncRNAs can affect protein populations by assembling dynamic ribonucleoprotein (RNP) granules. These phase-separated molecular ‘sponges’, stabilized by quinary (transient and weak) interactions, control proteins involved in numerous biological functions. Retroviruses such as HIV-1 form by self-assembly when their genomic RNA (gRNA) traps Gag and GagPol polyprotein precursors. Infectivity requires extracellular budding of the particle followed by maturation, an ordered processing of ∼2400 Gag and ∼120 GagPol by the viral protease (PR). This leads to a condensed gRNA-NCp7 nucleocapsid and a CAp24-self-assembled capsid surrounding the RNP. The choreography by which all of these components dynamically interact during virus maturation is one of the missing milestones to fully depict the HIV life cycle. Here, we describe how HIV-1 has evolved a dynamic RNP granule with successive weak–strong–moderate quinary NC-gRNA networks during the sequential processing of the GagNC domain. We also reveal two palindromic RNA-binding triads on NC, KxxFxxQ and QxxFxxK, that provide quinary NC-gRNA interactions. Consequently, the nucleocapsid complex appears properly aggregated for capsid reassembly and reverse transcription, mandatory processes for viral infectivity. We show that PR is sequestered within this RNP and drives its maturation/condensation within minutes, this process being most effective at the end of budding. We anticipate such findings will stimulate further investigations of quinary interactions and emergent mechanisms in crowded environments throughout the wide and growing array of RNP granules.

scholarly journals Cross-linking reveals laminin coiled-coil architecture

2016 ◽  
Vol 113 (47) ◽  
pp. 13384-13389 ◽  
Author(s):  
Gad Armony ◽  
Etai Jacob ◽  
Toot Moran ◽  
Yishai Levin ◽  
Tevie Mehlman ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Self Assembly ◽  
Quaternary Structure ◽  
Coiled Coil ◽  
Surface Proteins ◽  
Cross Linking ◽  
Single Particle Reconstruction ◽  
Cross Links ◽  
Particle Reconstruction ◽  
Key Questions

Laminin, an ∼800-kDa heterotrimeric protein, is a major functional component of the extracellular matrix, contributing to tissue development and maintenance. The unique architecture of laminin is not currently amenable to determination at high resolution, as its flexible and narrow segments complicate both crystallization and single-particle reconstruction by electron microscopy. Therefore, we used cross-linking and MS, evaluated using computational methods, to address key questions regarding laminin quaternary structure. This approach was particularly well suited to the ∼750-Å coiled coil that mediates trimer assembly, and our results support revision of the subunit order typically presented in laminin schematics. Furthermore, information on the subunit register in the coiled coil and cross-links to downstream domains provide insights into the self-assembly required for interaction with other extracellular matrix and cell surface proteins.

Self-Assembly of the Synthetic Polymer (Leu-Glu)n:  An Amyloid-like Structure Formation

Langmuir ◽  
2003 ◽  
Vol 19 (8) ◽  
pp. 3413-3418 ◽  
Author(s):  
Julia P. Moses ◽  
K. S. Satheeshkumar ◽  
J. Murali ◽  
D. Alli ◽  
R. Jayakumar
Keyword(s):  
Structure Formation ◽  
Self Assembly ◽  
Synthetic Polymer

scholarly journals Aβ(M1–40) and Wild-Type Aβ40 Self-Assemble into Oligomers with Distinct Quaternary Structures

Molecules ◽  
2019 ◽  
Vol 24 (12) ◽  
pp. 2242 ◽  
Author(s):  
Jacob L. Bouchard ◽  
Taylor C. Davey ◽  
Todd M. Doran
Keyword(s):  
Self Assembly ◽  
Quaternary Structure ◽  
Biological Activities ◽  
Amyloid Β ◽  
Long Term Potentiation ◽  
Wild Type ◽  
Molecular Weights ◽  
Term Potentiation ◽  
Quaternary Structures

Amyloid-β oligomers (AβOs) self-assemble into polymorphic species with diverse biological activities that are implicated causally to Alzheimer’s disease (AD). Synaptotoxicity of AβO species is dependent on their quaternary structure, however, low-abundance and environmental sensitivity of AβOs in vivo have impeded a thorough assessment of structure–function relationships. We developed a simple biochemical assay to quantify the relative abundance and morphology of cross-linked AβOs. We compared oligomers derived from synthetic Aβ40 (wild-type (WT) Aβ40) and a recombinant source, called Aβ(M1–40). Both peptides assemble into oligomers with common sizes and morphology, however, the predominant quaternary structures of Aβ(M1–40) oligomeric states were more diverse in terms of dispersity and morphology. We identified self-assembly conditions that stabilize high-molecular weight oligomers of Aβ(M1–40) with apparent molecular weights greater than 36 kDa. Given that mixtures of AβOs derived from both peptides have been shown to be potent neurotoxins that disrupt long-term potentiation, we anticipate that the diverse quaternary structures reported for Aβ(M1–40) oligomers using the assays reported here will facilitate research efforts aimed at isolating and identifying common toxic species that contribute to synaptic dysfunction.

Patterning: Structure Formation by Dynamic Self-Assembly (Small 4/2012)

Small ◽  
2012 ◽  
Vol 8 (4) ◽  
pp. 487-487 ◽  
Author(s):  
Liqiang Li ◽  
Michael H. Köpf ◽  
Svetlana V. Gurevich ◽  
Rudolf Friedrich ◽  
Lifeng Chi
Keyword(s):  
Structure Formation ◽  
Self Assembly

scholarly journals Immunogenicity of a Prefusion HIV-1 Envelope Trimer in Complex with a Quaternary-Structure-Specific Antibody

2015 ◽  
Vol 90 (6) ◽  
pp. 2740-2755 ◽  
Author(s):  
Cheng Cheng ◽  
Marie Pancera ◽  
Adam Bossert ◽  
Stephen D. Schmidt ◽  
Rita E. Chen ◽  
...  
Keyword(s):  
Guinea Pigs ◽  
Neutralizing Antibodies ◽  
Quaternary Structure ◽  
High Titer ◽  
Antigen Binding ◽  
Broadly Neutralizing Antibodies ◽  
Closed Conformation ◽  
Ligand Free ◽  
V3 Region ◽  
Hiv 1

ABSTRACTThe HIV-1 envelope trimer (Env) is the target of broadly neutralizing antibodies and is being explored as a vaccine candidate to elicit protective antibodies. One of the most promising antigenic and structural mimics of HIV-1 Env is the SOSIP.664-stabilized soluble trimer from the clade A strain BG505, which is preferentially recognized by broadly neutralizing antibodies. Trimer immunization elicits high-titer neutralization of the autologous tier 2 BG505 strain; however, breadth is limited, and substantial interest has focused on understanding and improving trimer immunogenicity. We sought to improve the antigenic specificity of BG505 SOSIP.664 by reducing recognition of the variable loop 3 (V3) region, which elicits only weakly neutralizing antibodies. To stabilize the trimer in its prefusion closed conformation, we complexed trimeric BG505 SOSIP.664 with the antigen-binding fragment (Fab) of PGT145, a broadly neutralizing quaternary-structure-specific antibody. Compared to the ligand-free trimer, the PGT145 Fab-BG505 SOSIP.664 complex displayed increased melting temperature stability and reduced V3 recognition. In guinea pigs, immunization with the PGT145 Fab-BG505 SOSIP.664 complex elicited ∼100-fold lower V3-directed binding and neutralization titers than those obtained with ligand-free BG505 SOSIP.664. Both complexed and ligand-free BG505 SOSIP.664 elicited comparable neutralization of the autologous BG505 virus, and in both cases, BG505 neutralization mapped to the outer domain of gp120 for some guinea pigs. Our results indicate that it is possible to reduce immune recognition of the V3 region of the trimer while maintaining the antigenic profile needed to induce autologous neutralizing antibodies. These data suggest that appropriate modifications of trimer immunogens could further focus the immune response on key neutralization epitopes.IMPORTANCEHIV-1 Env trimers have been proposed as preferred HIV-1 vaccine immunogens. One version, BG505 SOSIP.664, a soluble stabilized trimer, was recently shown to elicit high-titer autologous neutralizing antibodies (NAbs) in rabbits. Here we compared two immunogens: the ligand-free BG505 SOSIP.664 trimer and the same trimer bound to the antigen-binding fragment (Fab) of the PGT145 antibody, a broadly neutralizing antibody which recognizes the trimer at its membrane-distal apex. We hypothesized that the Fab-bound complex would stabilize BG505 SOSIP.664 in its prefusion closed conformation and limit reactivity to weakly neutralizing antibodies targeting the variable loop 3 (V3) region. In guinea pigs, the Fab-complexed trimer induced 100-fold lower responses to the V3 region, while both ligand-free and Fab-complexed trimers elicited similar levels of autologous NAbs. Our findings demonstrate the potential to reduce “off-target” immunogenicity while maintaining the capacity to generate autologous NAbs.

scholarly journals Free-standing supramolecular hydrogel objects by reaction-diffusion

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Matija Lovrak ◽  
Wouter E. J. Hendriksen ◽  
Chandan Maity ◽  
Serhii Mytnyk ◽  
Volkert van Steijn ◽  
...  
Keyword(s):  
Structure Formation ◽  
Self Assembly ◽  
Reaction Diffusion ◽  
Building Blocks ◽  
Assembly Process ◽  
Supramolecular Hydrogel ◽  
Free Standing ◽  
Spatial Control ◽  
Self Assembling ◽  
Vast Range

Abstract Self-assembly provides access to a variety of molecular materials, yet spatial control over structure formation remains difficult to achieve. Here we show how reaction–diffusion (RD) can be coupled to a molecular self-assembly process to generate macroscopic free-standing objects with control over shape, size, and functionality. In RD, two or more reactants diffuse from different positions to give rise to spatially defined structures on reaction. We demonstrate that RD can be used to locally control formation and self-assembly of hydrazone molecular gelators from their non-assembling precursors, leading to soft, free-standing hydrogel objects with sizes ranging from several hundred micrometres up to centimeters. Different chemical functionalities and gradients can easily be integrated in the hydrogel objects by using different reactants. Our methodology, together with the vast range of organic reactions and self-assembling building blocks, provides a general approach towards the programmed fabrication of soft microscale objects with controlled functionality and shape.

scholarly journals Resistance to V3-Directed Neutralization Caused by an N-Linked Oligosaccharide Depends on the Quaternary Structure of the HIV-1 Envelope Oligomer

Virology ◽  
1996 ◽  
Vol 218 (1) ◽  
pp. 134-140 ◽  
Author(s):  
KRISTIAN SCHØNNING ◽  
BRITT JANSSON ◽  
SIGVARD OLOFSSON ◽  
JENS OLE NIELSEN ◽  
JOHN-ERIK STIG HANSEN
Keyword(s):  
Quaternary Structure ◽  
Hiv 1

scholarly journals 2,2′-Bipyridine and hydrazide containing peptides for cyclization and complex quaternary structural control

2018 ◽  
Vol 42 (11) ◽  
pp. 8577-8582 ◽  
Author(s):  
Erik T. Hernandez ◽  
P. Rogelio Escamilla ◽  
Sang-Yop Kwon ◽  
Jonathan Partridge ◽  
Matthew McVeigh ◽  
...  
Keyword(s):  
Structure Formation ◽  
Structural Control ◽  
Quaternary Structure ◽  
Peptide Ligands

Complex quaternary structure formation of bipy peptide ligands.

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