Synthesis of Metal Core in the Apoferritin Cavity

2012 ◽  
Vol 549 ◽  
pp. 216-220
Author(s):  
Ting Wang
Keyword(s):  
Particle Size ◽  
Electrostatic Interactions ◽  
Molecular Level ◽  
Reaction Vessel ◽  
Inorganic Materials ◽  
Metal Core ◽  
Protein Cages ◽  
Protein Cage ◽  
Protein Cavity ◽  
Uniform Particle Size

Many methods to produce NPs have been studied. Among them, the molecular level understanding of the formation of solids in biological systems has provided inspiration for the controlled formation of novel inorganic materials. The use of a protein cavity as the growth field of NPs provides one candidate method for obtaining uniform particle size. The host-guest relationship between these protein cages and the encapsulated material is based primarily on a complementary electrostatic interaction. Charged interfaces play important roles in defining electrostatically distinct environments for spatially defined encapsulation. The electrostatic interactions can be approximated by Guoy-Chapman theory of charged interfaces. These interactions are proposed at the interior of protein cages such as ferritin and viruses. The protein cage with a highly charged interior surface with pores that allow molecular access to the inside of the protein could act as a constrained reaction vessel. The present paper will focus on the synthesis of Metal NPs using ferritin.

scholarly journals Polyelectrolyte Encapsulation and Confinement within Protein Cage-Inspired Nanocompartments

Pharmaceutics ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1551
Author(s):  
Qing Liu ◽  
Ahmed Shaukat ◽  
Daniella Kyllönen ◽  
Mauri A. Kostiainen
Keyword(s):  
Small Molecules ◽  
Driving Force ◽  
Electrostatic Interactions ◽  
Inorganic Nanoparticles ◽  
Wild Type ◽  
Potential Toxicity ◽  
Protein Cages ◽  
Functional Sites ◽  
Protein Cage ◽  
Or Gene

Protein cages are nanocompartments with a well-defined structure and monodisperse size. They are composed of several individual subunits and can be categorized as viral and non-viral protein cages. Native viral cages often exhibit a cationic interior, which binds the anionic nucleic acid genome through electrostatic interactions leading to efficient encapsulation. Non-viral cages can carry various cargo, ranging from small molecules to inorganic nanoparticles. Both cage types can be functionalized at targeted locations through genetic engineering or chemical modification to entrap materials through interactions that are inaccessible to wild-type cages. Moreover, the limited number of constitutional subunits ease the modification efforts, because a single modification on the subunit can lead to multiple functional sites on the cage surface. Increasing efforts have also been dedicated to the assembly of protein cage-mimicking structures or templated protein coatings. This review focuses on native and modified protein cages that have been used to encapsulate and package polyelectrolyte cargos and on the electrostatic interactions that are the driving force for the assembly of such structures. Selective encapsulation can protect the payload from the surroundings, shield the potential toxicity or even enhance the intended performance of the payload, which is appealing in drug or gene delivery and imaging.

The MrgA Multimeric Complex: a self-assembled nanostructure for inorganic synthesis

2003 ◽  
Vol 776 ◽  
Author(s):  
Ryan M. Kramer ◽  
Amritraj G. Loganathan ◽  
Rajesh R. Naik ◽  
Morley Stone
Keyword(s):  
Materials Science ◽  
Inorganic Materials ◽  
Internal Cavity ◽  
Inorganic Synthesis ◽  
Viral Capsids ◽  
Protein Cages ◽  
Protein Cage ◽  
Recombinant Production ◽  
Multimeric Complex ◽  
High Sequence Homology

AbstractUtilization of protein cages in biomimetic chemistry allows for the deposition of inorganic materials within an organic construct, controlling the size and amount of material deposited within a constrained reaction environment. Previously, protein cages such as viral capsids and ferritins have been used in the constrained synthesis of inorganic materials. The MrgA protein displays a high sequence homology to both bacterial DNA-protecting proteins (Dps) found in many bacterial genera and Ferritin-like proteins (Flp), which have been shown to functionally sequester and store iron in a biologically available form. Here we demonstrate recombinant production, purification and characterization of the MrgA protein and provide evidence that this protein self-assembles to form a multimeric complex. This complex demonstrates characteristics similar to that of ferritin-like proteins such as resistance to iron toxicity, iron incorporation, and resistance to thermal and chemical denaturation. The ability to deposit iron within the putative internal cavity of this protein cage will allow the MrgA complex to be utilized as a spatially constrained reaction vessel for nanomaterial synthesis of other inorganic materials. From a materials science perspective, it will be interesting to see if these organic/inorganic hybrid materials can be harnessed for catalysis, nanomagnetics, and other applications.

scholarly journals In vitro-reassembled plant virus-like particles for loading of polyacids

2006 ◽  
Vol 87 (9) ◽  
pp. 2749-2754 ◽  
Author(s):  
Yupeng Ren ◽  
Sek-Man Wong ◽  
Lee-Yong Lim
Keyword(s):  
Electrostatic Interactions ◽  
Plant Viruses ◽  
Virus Like Particles ◽  
Protein Cages ◽  
Large Molecules ◽  
Protein Cage ◽  
Drug Molecules ◽  
Structural Conformation ◽  
Foreign Materials

The coat protein (CP) of certain plant viruses may reassemble into empty virus-like particles (VLPs) and these protein cages may serve as potential drug delivery platforms. In this paper, the production of novel VLPs from the Hibiscus chlorotic ringspot virus (HCRSV) is reported and the capacity to load foreign materials was characterized. VLPs were readily produced by destabilizing the HCRSV in 8 M urea or Tris buffer pH 8, in the absence of calcium ions, followed by removal of viral RNA by ultrahigh-speed centrifugation and the reassembly of the CP in sodium acetate buffer pH 5. The loading of foreign materials into the VLPs was dependent on electrostatic interactions. Anionic polyacids, such as polystyrenesulfonic acid and polyacrylic acid, were successfully loaded but neutrally charged dextran molecules were not. The molecular-mass threshold for the polyacid cargo was about 13 kDa, due to the poor retention of smaller molecules, which readily diffused through the holes between the S domains present on the surface of the VLPs. These holes precluded the entry of large molecules, but allowed smaller molecules to enter or exit. The polyacid-loaded VLPs had comparable size, morphology and surface-charge density to the native HCRSV, and the amount of polyacids loaded was comparable to the weight of the native genomic materials. The conditions applied to disassembly–reassembly of the virions did not change the structural conformation of the CP. HCRSV-derived VLPs may provide a promising nano-sized protein cage for delivery of anionic drug molecules.

Shot-noise simulations of HREM images of polymer crystals

1989 ◽  
Vol 47 ◽  
pp. 342-343
Author(s):  
Philippe Pradère ◽  
Edwin L. Thomas
Keyword(s):  
Low Dose ◽  
Molecular Level ◽  
High Resolution Electron Microscopy ◽  
Crystal Defects ◽  
Inorganic Materials ◽  
Photographic Emulsion ◽  
Polymer Crystals ◽  
Resolution Electron ◽  
Recent Developments ◽  
Lattice Images

High Resolution Electron Microscopy (HREM) is a very powerful technique for the study of crystal defects at the molecular level. Unfortunately polymer crystals are beam sensitive and are destroyed almost instantly under the typical HREM imaging conditions used for inorganic materials. Recent developments of low dose imaging at low magnification have nevertheless permitted the attainment of lattice images of very radiation sensitive polymers such as poly-4-methylpentene-1 and enabled molecular level studies of crystal defects in somewhat more resistant ones such as polyparaxylylene (PPX) [2].With low dose conditions the images obtained are very noisy. Noise arises from the support film, photographic emulsion granularity and in particular, the statistical distribution of electrons at the typical doses of only few electrons per unit resolution area. Figure 1 shows the shapes of electron distribution, according to the Poisson formula :

scholarly journals Laboratory evolution of virus-like nucleocapsids from nonviral protein cages

2018 ◽  
Vol 115 (21) ◽  
pp. 5432-5437 ◽  
Author(s):  
Naohiro Terasaka ◽  
Yusuke Azuma ◽  
Donald Hilvert
Keyword(s):  
Aquifex Aeolicus ◽  
Cellular Functions ◽  
Laboratory Evolution ◽  
Virion Assembly ◽  
Protein Cages ◽  
Protein Cage ◽  
Spherical Structures ◽  
Rna Genome ◽  
Biological Environment

Viruses are remarkable nanomachines that efficiently hijack cellular functions to replicate and self-assemble their components within a complex biological environment. As all steps of the viral life cycle depend on formation of a protective proteinaceous shell that packages the DNA or RNA genome, bottom-up construction of virus-like nucleocapsids from nonviral materials could provide valuable insights into virion assembly and evolution. Such constructs could also serve as safe alternatives to natural viruses for diverse nano- and biotechnological applications. Here we show that artificial virus-like nucleocapsids can be generated—rapidly and surprisingly easily—by engineering and laboratory evolution of a nonviral protein cage formed by Aquifex aeolicus lumazine synthase (AaLS) and its encoding mRNA. Cationic peptides were appended to the engineered capsid proteins to enable specific recognition of packaging signals on cognate mRNAs, and subsequent evolutionary optimization afforded nucleocapsids with expanded spherical structures that encapsulate their own full-length RNA genome in vivo and protect the cargo molecules from nucleases. These findings provide strong experimental support for the hypothesis that subcellular protein-bounded compartments may have facilitated the emergence of ancient viruses.

scholarly journals Filter Cake Utilization as Filler of 15-15-15+5S Compound Fertilizer: Particle Size Distribution and Granule Crushing Strength Properties

REAKTOR ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 145-151
Author(s):  
Kasmadi Kasmadi ◽  
Budi Nugroho ◽  
Atang Sutandi ◽  
Syaiful Anwar
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Filter Cake ◽  
Rotation Speed ◽  
Strength Properties ◽  
Inorganic Materials ◽  
Crushing Strength ◽  
Compound Fertilizer ◽  
Potassium Sources

Compound fertilizer which combining organic-inorganic materials need to be developed to improve the effectivness of fertilizers in the soil. Filter cake as a material has highly potential to be used as a filler in physical process granulation of compound fertilizer. In this study, the particle size distribution and granule crushing strength properties were tested using 15-15-15 + 5S fertilizer compound formula, which are varied in the filler composition and K sources. Potassium sources consisted of 2 (two) types of fertilizers i.e KCl and K2SO4. Filler composition as a binder in fertilizer granulation consists of 5 combination filter cake and clay ratios (60:40, 70:30, 80:20, 90:10 and 100:0). Granulation carried out by the granulation method using pan granulator of 2 kg/batch capacity, 23 rpm rotation speed and 50o pan slope. The results of the research showed that statistically the combination of filter cake and clay 70:30 had a size distribution and hardness of granules not significantly different from standard fertilizer (100% clay). Keywords: crushing strength; filler; filter cake; granulation; size distribution

The Development and Evaluation of a Four-roller Flour Mill with Parallelogram Configuration

2007 ◽  
Vol 3 (6) ◽  
Author(s):  
John Alaba Victor Famurewa
Keyword(s):  
Particle Size ◽  
Opposite Direction ◽  
Size Reduction ◽  
Sieve Analysis ◽  
Feeding Problems ◽  
Roller Mill ◽  
Flour Mill ◽  
Wide Gap ◽  
Uniform Particle Size ◽  
Milled Product

A roller mill was designed and evaluated using four equal size cylindrical rollers with their centers on vertices of a parallelogram. The relative speeds and opposite direction of rotation of the rollers allowed the discharge of the materials on them, and splitting took place in between the first pair of corrugated rollers. The broken seeds were directed towards the second and third nips where adequate size reduction was accomplished consecutively by smooth rollers. The milled products were separated into three fractions: chaff, flour and size larger than flour. The chaff and the flour are collected at different outlets, while the particles with sizes larger than flour are blown back into the hopper for further reduction. The mill was evaluated using three grains: maize, beans and soy beans at different combinations of evaluating parameters. The machine was able to mill grains to flour size without any leakage at the nip points. For all the grains, a wide gap set produced higher throughput than narrow, as well as fast feeding in smaller particle size and higher throughput. The results obtained from the evaluation showed that the machine is very capable of three-stage size reduction to produce flour, avoiding the feeding problems in three high roller mills. Sieve analysis of the milled product for each experiment showed uniform particle size.

Reduction of SSI by Hydrogen and its Microscopic Morphology

2012 ◽  
Vol 487 ◽  
pp. 672-676
Author(s):  
Jun Guo Li ◽  
Wei Tian ◽  
Shou Zhang Li
Keyword(s):  
Particle Size ◽  
Compressive Strength ◽  
Wastewater Treatment ◽  
High Activity ◽  
Iron Content ◽  
Sponge Iron ◽  
Reduction Temperature ◽  
Microscopic Morphology ◽  
Uniform Particle Size

Spherical sponge iron (SSI) with high activity and intension possesses potential characteristics to be utilized as wastewater treatment material, such as higher iron content, uniform particle size, higher compressive strength, etc. Observation on apparent morphology of exterior and microscopic morphology of SSI reduced by hydrogen under different temperature was carried on with SEM. When the reductive temperature was relatively lower than T4, the quantities of iron grain in exterior and interior of SSI increased with the increasing of temperature. When the temperature was elevated to T5, the particle size of iron grain was increased, and lots of macro-holes formed, especially in the interior section of SSI. When the temperature was T4, the SSI possesses more favorable ability to remove pollutant from wastewater. Moreover, the iron content in SSI was mostly reach to the summit under this temperature. In summarization, the reduction temperature should be controlled under T4 temperature if the sponge iron was utilized in wastewater treatment.

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