Estimation of drying length during particle assembly by convective deposition

ABSTRACT The nucleocapsid (NC) domains of retrovirus precursor Gag (PrGag) proteins play an essential role in virus assembly. Evidence suggests that NC binding to viral RNA promotes dimerization of PrGag capsid (CA) domains, which triggers assembly of CA N-terminal domains (NTDs) into hexamer rings that are interconnected by CA C-terminal domains. To examine the influence of dimerization on human immunodeficiency virus type 1 (HIV-1) Gag protein assembly in vitro, we analyzed the assembly properties of Gag proteins in which NC domains were replaced with cysteine residues that could be linked via chemical treatment. In accordance with the model that Gag protein pairing triggers assembly, we found that cysteine cross-linking or oxidation reagents induced the assembly of virus-like particles. However, efficient assembly also was observed to be temperature dependent or required the tethering of NTDs. Our results suggest a multistep pathway for HIV-1 Gag protein assembly. In the first step, Gag protein pairing through NC-RNA interactions or C-terminal cysteine linkage fosters dimerization. Next, a conformational change converts assembly-restricted dimers or small oligomers into assembly-competent ones. At the final stage, final particle assembly occurs, possibly through a set of larger intermediates.

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Are phytoplankton population density maxima predictable through analysis of host and viral genomic DNA content?

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315406013397 ◽

2006 ◽

Vol 86 (3) ◽

pp. 491-498 ◽

Cited By ~ 27

Author(s):

Chris M. Brown ◽

Janice E. Lawrence ◽

Douglas A. Campbell

Keyword(s):

Population Density ◽

Dna Content ◽

Viral Genome ◽

Particle Assembly ◽

Phytoplankton Population ◽

Strong Linear Correlation ◽

Viral Progeny ◽

A Cell ◽

Viral Proliferation ◽

Viral Particle Assembly

Phytoplankton:virus interactions are important factors in aquatic nutrient cycling and community succession. The number of viral progeny resulting from an infection of a cell critically influences the propagation of infection and concomitantly the dynamics of phytoplankton populations. Host nucleotide content may be the resource limiting viral particle assembly. We present evidence for a strong linear correlation between measured viral burst sizes and viral burst sizes predicted from the host DNA content divided by the viral genome size, across a diversity of phytoplankton:viral pairs. An analysis of genome sizes therefore supports predictions of taxon-specific phytoplankton population density thresholds beyond which viral proliferation can trim populations or terminate phytoplankton blooms. We present corollaries showing that host:virus interactions may place evolutionary pressure towards genome reduction of both phytoplankton hosts and their viruses.

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Dynamics of magnetic nano-particle assembly

Journal of Physics Conference Series ◽

10.1088/1742-6596/248/1/012027 ◽

2010 ◽

Vol 248 ◽

pp. 012027 ◽

Cited By ~ 2

Author(s):

V N Kondratyev

Keyword(s):

Nano Particle ◽

Particle Assembly

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Validation of the similar particle assembly (SPA) model for the fluidization of Geldart's group A and D particles

AIChE Journal ◽

10.1002/aic.12568 ◽

2011 ◽

Vol 58 (1) ◽

pp. 87-98 ◽

Cited By ~ 29

Author(s):

M. A. Mokhtar ◽

K. Kuwagi ◽

T. Takami ◽

H. Hirano ◽

M. Horio

Keyword(s):

Particle Assembly ◽

Group A ◽

Spa Model

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Pair directed silver nano-lines by single-particle assembly in nanofibers for non-contact humidity sensors

Nano Energy ◽

10.1016/j.nanoen.2021.106748 ◽

2021 ◽

pp. 106748

Author(s):

Jing He ◽

Xiaotong Zheng ◽

Zhiwen Zheng ◽

Degang Kong ◽

Kai Ding ◽

...

Keyword(s):

Single Particle ◽

Humidity Sensors ◽

Particle Assembly

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Solution-based Ni-Al2O3 Solar Selective Coating using Convective Deposition

Materials Today Proceedings ◽

10.1016/j.matpr.2019.12.268 ◽

2020 ◽

Vol 23 ◽

pp. 745-751

Author(s):

Thatchai Chevapruk ◽

Narin Chomcharoen ◽

Ratchatee Techapiesancharoenkij ◽

Pisist Kumnorkaew ◽

Tanyakorn Muangnapoh ◽

...

Keyword(s):

Selective Coating ◽

Convective Deposition

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Control of Designed High-Order DNA Conformation as a Template for Nano Particle Assembly

KOBUNSHI RONBUNSHU ◽

10.1295/koron.61.617 ◽

2004 ◽

Vol 61 (12) ◽

pp. 617-622 ◽

Cited By ~ 5

Author(s):

Yoshiharu HATAKEYAMA ◽

Masahiro MINAMI ◽

Mitsuo UMETSU ◽

Satoshi OHARA ◽

Seiichi TAKAMI ◽

...

Keyword(s):

High Order ◽

Dna Conformation ◽

Nano Particle ◽

Particle Assembly

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Identification of a Structural Element in HIV-1 Gag Required for Virus Particle Assembly and Maturation

mBio ◽

10.1128/mbio.01567-18 ◽

2018 ◽

Vol 9 (5) ◽

Cited By ~ 6

Author(s):

Mariia Novikova ◽

Lucas J. Adams ◽

Juan Fontana ◽

Anna T. Gres ◽

Muthukumar Balasubramaniam ◽

...

Keyword(s):

Virus Assembly ◽

Critical Role ◽

Replication Cycle ◽

Structural Defects ◽

Fold Axis ◽

Structural Element ◽

Particle Assembly ◽

Compensatory Mutations ◽

Hiv 1 ◽

Selection Of

ABSTRACTLate in the HIV-1 replication cycle, the viral structural protein Gag is targeted to virus assembly sites at the plasma membrane of infected cells. The capsid (CA) domain of Gag plays a critical role in the formation of the hexameric Gag lattice in the immature virion, and, during particle release, CA is cleaved from the Gag precursor by the viral protease and forms the conical core of the mature virion. A highly conserved Pro-Pro-Ile-Pro (PPIP) motif (CA residues 122 to 125) [PPIP(122–125)] in a loop connecting CA helices 6 and 7 resides at a 3-fold axis formed by neighboring hexamers in the immature Gag lattice. In this study, we characterized the role of this PPIP(122–125) loop in HIV-1 assembly and maturation. While mutations P123A and P125A were relatively well tolerated, mutation of P122 and I124 significantly impaired virus release, caused Gag processing defects, and abolished infectivity. X-ray crystallography indicated that the P122A and I124A mutations induce subtle changes in the structure of the mature CA lattice which were permissive forin vitroassembly of CA tubes. Transmission electron microscopy and cryo-electron tomography demonstrated that the P122A and I124A mutations induce severe structural defects in the immature Gag lattice and abrogate conical core formation. Propagation of the P122A and I124A mutants in T-cell lines led to the selection of compensatory mutations within CA. Our findings demonstrate that the CA PPIP(122–125) loop comprises a structural element critical for the formation of the immature Gag lattice.IMPORTANCECapsid (CA) plays multiple roles in the HIV-1 replication cycle. CA-CA domain interactions are responsible for multimerization of the Gag polyprotein at virus assembly sites, and in the mature virion, CA monomers assemble into a conical core that encapsidates the viral RNA genome. Multiple CA regions that contribute to the assembly and release of HIV-1 particles have been mapped and investigated. Here, we identified and characterized a Pro-rich loop in CA that is important for the formation of the immature Gag lattice. Changes in this region disrupt viral production and abrogate the formation of infectious, mature virions. Propagation of the mutants in culture led to the selection of second-site compensatory mutations within CA. These results expand our knowledge of the assembly and maturation steps in the viral replication cycle and may be relevant for development of antiviral drugs targeting CA.

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Shaping nanoparticle fingerprints at the interface of cholesteric droplets

Science Advances ◽

10.1126/sciadv.aat8597 ◽

2018 ◽

Vol 4 (10) ◽

pp. eaat8597 ◽

Cited By ~ 9

Author(s):

Lisa Tran ◽

Hye-Na Kim ◽

Ningwei Li ◽

Shu Yang ◽

Kathleen J. Stebe ◽

...

Keyword(s):

Liquid Crystals ◽

Periodic Structures ◽

Water Solution ◽

Cholesteric Liquid Crystal ◽

Solution Ph ◽

Surrounding Water ◽

Particle Assembly ◽

Interfacial Assembly ◽

Energy Applications ◽

Geometric Frustration

The ordering of nanoparticles into predetermined configurations is of importance to the design of advanced technologies. Here, we balance the interfacial energy of nanoparticles against the elastic energy of cholesteric liquid crystals to dynamically shape nanoparticle assemblies at a fluid interface. By adjusting the concentration of surfactant that plays the dual role of tuning the degree of nanoparticle hydrophobicity and altering the molecular anchoring of liquid crystals, we pattern nanoparticles at the interface of cholesteric liquid crystal emulsions. In this system, interfacial assembly is tempered by elastic patterns that arise from the geometric frustration of confined cholesterics. Patterns are tunable by varying both surfactant and chiral dopant concentrations. Adjusting the particle hydrophobicity more finely by regulating the surfactant concentration and solution pH further modifies the rigidity of assemblies, giving rise to surprising assembly dynamics dictated by the underlying elasticity of the cholesteric. Because particle assembly occurs at the interface with the desired structures exposed to the surrounding water solution, we demonstrate that particles can be readily cross-linked and manipulated, forming structures that retain their shape under external perturbations. This study serves as a foundation for better understanding inter-nanoparticle interactions at interfaces by tempering their assembly with elasticity and for creating materials with chemical heterogeneity and linear, periodic structures, essential for optical and energy applications.

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