scholarly journals Protein Transduction Domain Mimic (PTDM) Self-Assembly?

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1039 ◽  
Author(s):  
Nicholas D. Posey ◽  
Gregory N. Tew
Keyword(s):  
Self Assembly ◽  
Protein Delivery ◽  
Protein Complexes ◽  
Aqueous Media ◽  
Protein Transduction ◽  
Cellular Processes ◽  
Transmission Electron ◽  
Invaluable Tool ◽  
Therapeutic Development ◽  
Intracellular Protein Delivery

Intracellular protein delivery is an invaluable tool for biomedical research, as it enables fundamental studies of cellular processes and creates opportunities for novel therapeutic development. Protein delivery reagents such as cell penetration peptides (CPPs) and protein transduction domains (PTDs) are frequently used to facilitate protein delivery. Herein, synthetic polymer mimics of PTDs, called PTDMs, were studied for their ability to self-assemble in aqueous media as it was not known whether self-assembly plays a role in the protein binding and delivery process. The results obtained from interfacial tensiometry (IFT), transmission electron microscopy (TEM), transmittance assays (%T), and dynamic light scattering (DLS) indicated that PTDMs do not readily aggregate or self-assemble at application-relevant time scales and concentrations. However, additional DLS experiments were used to confirm that the presence of protein is required to induce the formation of PTDM-protein complexes and that PTDMs likely bind as single chains.

Copolymer Nanoparticles Prepared by Self-Assembly of Poly(ethylene glycol) and Poly-γ-Glutamic Acid and its Characteristics

2013 ◽  
Vol 662 ◽  
pp. 136-139
Author(s):  
Ge Yang ◽  
Ke Shuai Lu ◽  
Xue Yan Su
Keyword(s):  
Ethylene Glycol ◽  
Glutamic Acid ◽  
Size Distribution ◽  
Self Assembly ◽  
Aqueous Media ◽  
Poly Ethylene Glycol ◽  
Polyelectrolyte Complexes ◽  
Self Assembling ◽  
Transmission Electron ◽  
Poly Ethylene

The paper describes the preparation and characterization of novel biodegradable nanoparticles based on self-assembly of poly-gamma-glutamic acid (γ-PGA) and poly(ethylene glycol) (PEG). The nanosystems were stable in aqueous media at low pH conditions. Solubility of the systems was determined by turbidity measurements. The particle size and the size distribution of the polyelectrolyte complexes were identified by dynamic lightscattering and transmission electron microscopy.It was found that the size and size distribution of the nanosystems depends on the concentrations of γ-PGA and PEG solutions and their ratio as well as on the pH of the mixture and the order of addition. The diameter of individual particles was in the range of 30–270 nm. measured by TEM, and the average hydrodynamic diameters were between 130 and 300 nm. These biodegradable, self-assembling stable nanocomplexes might be useful for several biomedical applications.

scholarly journals Control over size, shape, and photonics of self-assembled organic nanocrystals

2020 ◽  
Author(s):  
Chen Shahar ◽  
Yaron Tidhar ◽  
Yunmin Jung ◽  
Haim Weissman ◽  
Sidney R Cohen ◽  
...  
Keyword(s):  
Self Assembly ◽  
Transient Absorption ◽  
Aqueous Media ◽  
Excitation Energy Transfer ◽  
Building Blocks ◽  
Transient Absorption Spectroscopy ◽  
Organic Nanocrystals ◽  
Femtosecond Transient Absorption ◽  
Transmission Electron ◽  
And Function

Facile fabrication of free-floating organic nanocrystals (ONCs) was achieved via kinetically controlled self-assembly of simple amphiphilic perylene diimide building blocks in aqueous media. The ONCs have a thin rectangular shape, with the aspect ratio that is controlled via organic co-solvent (THF) content. The nanocrystals were characterized in solution by cryogenic transmission electron microscopy (cryo-TEM) and small angle X-ray scattering (SAXS); the ONCs retain their structure upon drying as was evidenced by TEM and AFM. Photophysical studies, including femtosecond transient absorption spectroscopy, revealed a distinct influence of the ONC morphology on their photonic properties (excitation energy transfer was observed only in the high aspect ONCs). Convenient control over structure and function of organic nanocrystals can enhance their utility in new and developed technologies.

scholarly journals Templated Self-Assembly of a Covalent Polymer Network for Intracellular Protein Delivery and Traceless Release

2017 ◽  
Vol 139 (16) ◽  
pp. 5676-5679 ◽  
Author(s):  
Kingshuk Dutta ◽  
Ding Hu ◽  
Bo Zhao ◽  
Alexander E. Ribbe ◽  
Jiaming Zhuang ◽  
...  
Keyword(s):  
Self Assembly ◽  
Protein Delivery ◽  
Polymer Network ◽  
Intracellular Protein ◽  
Intracellular Protein Delivery

Structure of contact sites between the outer and inner mitochondrial membranes investigated by HVEM tomography

1996 ◽  
Vol 54 ◽  
pp. 966-967
Author(s):  
C.A. Mannella ◽  
K.F. Buttle ◽  
K.A. O‘Farrell ◽  
A. Leith ◽  
M. Marko
Keyword(s):  
Liver Mitochondrion ◽  
Adenine Nucleotide ◽  
Protein Complexes ◽  
Mitochondrial Membranes ◽  
Electron Microscopic ◽  
Contact Sites ◽  
Transmission Electron ◽  
Precursor Proteins ◽  
Membrane Contacts ◽  
And Function

Early transmission electron microscopy of plastic-embedded, thin-sectioned mitochondria indicated that there are numerous junctions between the outer and inner membranes of this organelle. More recent studies have suggested that the mitochondrial membrane contacts may be the site of protein complexes engaged in specialized functions, e.g., import of mitochondrial precursor proteins, adenine nucleotide channeling, and even intermembrane signalling. It has been suggested that the intermembrane contacts may be sites of membrane fusion involving non-bilayer lipid domains in the two membranes. However, despite growing interest in the nature and function of intramitochondrial contact sites, little is known about their structure.We are using electron microscopic tomography with the Albany HVEM to determine the internal organization of mitochondria. We have reconstructed a 0.6-μm section through an isolated, plasticembedded rat-liver mitochondrion by combining 123 projections collected by tilting (+/- 70°) around two perpendicular tilt axes. The resulting 3-D image has confirmed the basic inner-membrane organization inferred from lower-resolution reconstructions obtained from single-axis tomography.

E3 ubiquitin ligases

2005 ◽  
Vol 41 ◽  
pp. 15-30 ◽  
Author(s):  
Helen C. Ardley ◽  
Philip A. Robinson
Keyword(s):  
Protein Complexes ◽  
Loss Of Function ◽  
Direct Role ◽  
Cellular Processes ◽  
Substrate Protein ◽  
Protein Ubiquitination ◽  
C Terminus ◽  
Full Complement ◽  
Spatio Temporal ◽  
Eukaryotic Organisms

The selectivity of the ubiquitin–26 S proteasome system (UPS) for a particular substrate protein relies on the interaction between a ubiquitin-conjugating enzyme (E2, of which a cell contains relatively few) and a ubiquitin–protein ligase (E3, of which there are possibly hundreds). Post-translational modifications of the protein substrate, such as phosphorylation or hydroxylation, are often required prior to its selection. In this way, the precise spatio-temporal targeting and degradation of a given substrate can be achieved. The E3s are a large, diverse group of proteins, characterized by one of several defining motifs. These include a HECT (homologous to E6-associated protein C-terminus), RING (really interesting new gene) or U-box (a modified RING motif without the full complement of Zn2+-binding ligands) domain. Whereas HECT E3s have a direct role in catalysis during ubiquitination, RING and U-box E3s facilitate protein ubiquitination. These latter two E3 types act as adaptor-like molecules. They bring an E2 and a substrate into sufficiently close proximity to promote the substrate's ubiquitination. Although many RING-type E3s, such as MDM2 (murine double minute clone 2 oncoprotein) and c-Cbl, can apparently act alone, others are found as components of much larger multi-protein complexes, such as the anaphase-promoting complex. Taken together, these multifaceted properties and interactions enable E3s to provide a powerful, and specific, mechanism for protein clearance within all cells of eukaryotic organisms. The importance of E3s is highlighted by the number of normal cellular processes they regulate, and the number of diseases associated with their loss of function or inappropriate targeting.

Bottom-up Evolution from Disks to High-Genus Polymersomes

2018 ◽  
Author(s):  
Claudia Contini ◽  
Russell Pearson ◽  
Linge Wang ◽  
Lea Messager ◽  
Jens Gaitzsch ◽  
...  
Keyword(s):  
Self Assembly ◽  
The Self ◽  
Amphiphilic Copolymers ◽  
Chain Entanglement ◽  
Bottom Up ◽  
New Approach ◽  
High Genus ◽  
Transmission Electron ◽  
Minimal Radius ◽  
Stop Flow

<div><div><div><p>We report the design of polymersomes using a bottom-up approach where the self-assembly of amphiphilic copolymers poly(2-(methacryloyloxy) ethyl phosphorylcholine)–poly(2-(diisopropylamino) ethyl methacrylate) (PMPC-PDPA) into membranes is tuned using pH and temperature. We study this process in detail using transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) spectroscopy, dynamic light scattering (DLS), and stop-flow ab- sorbance disclosing the molecular and supramolecular anatomy of each structure observed. We report a clear evolution from disk micelles to vesicle to high-genus vesicles where each passage is controlled by pH switch or temperature. We show that the process can be rationalised adapting membrane physics theories disclosing important scaling principles that allow the estimation of the vesiculation minimal radius as well as chain entanglement and coupling. This allows us to propose a new approach to generate nanoscale vesicles with genus from 0 to 70 which have been very elusive and difficult to control so far.</p></div></div></div>

Bottom-up Evolution from Disks to High-Genus Polymersomes

2018 ◽  
Author(s):  
Claudia Contini ◽  
Russell Pearson ◽  
Linge Wang ◽  
Lea Messager ◽  
Jens Gaitzsch ◽  
...  
Keyword(s):  
Self Assembly ◽  
The Self ◽  
Amphiphilic Copolymers ◽  
Chain Entanglement ◽  
Bottom Up ◽  
New Approach ◽  
High Genus ◽  
Transmission Electron ◽  
Minimal Radius ◽  
Stop Flow

<div><div><div><p>We report the design of polymersomes using a bottom-up approach where the self-assembly of amphiphilic copolymers poly(2-(methacryloyloxy) ethyl phosphorylcholine)–poly(2-(diisopropylamino) ethyl methacrylate) (PMPC-PDPA) into membranes is tuned using pH and temperature. We study this process in detail using transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) spectroscopy, dynamic light scattering (DLS), and stop-flow ab- sorbance disclosing the molecular and supramolecular anatomy of each structure observed. We report a clear evolution from disk micelles to vesicle to high-genus vesicles where each passage is controlled by pH switch or temperature. We show that the process can be rationalised adapting membrane physics theories disclosing important scaling principles that allow the estimation of the vesiculation minimal radius as well as chain entanglement and coupling. This allows us to propose a new approach to generate nanoscale vesicles with genus from 0 to 70 which have been very elusive and difficult to control so far.</p></div></div></div>

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