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Computational Modeling of Nanoparticles
Published in Sarhan M. Musa, ®, 2018
The sum runs over all ions. Nanodiscs are nanometer-sized lipid bilayers, which are stabilized by amphipathic proteins. They provide a platform in which to embed, solubilize, and study single membrane proteins. Membrane proteins can be difficult to study experimentally and are often studied under non-native conditions such as in high concentrations of detergents and in micelles. It is therefore desirable to be able to study membrane proteins, especially integral membrane proteins, in a more native lipid bilayer environment. This has motivated scientists to engineer nanometer-sized discoidal lipid bilayers stabilized by amphipathic helical proteins, termed nanodiscs, which furnish the desired nanoenvironment for membrane proteins. Nanodiscs are homogeneous protein-lipid particles of discrete size and composition [72]. The proteins forming nanodiscs are uniquely engineered to solubilize a small lipid bilayer. These proteins, termed membrane scaffold proteins, are long helical amphipathic proteins, having a hydrophobic face and a hydrophilic face.
Nanobased Cns Delivery Systems
Published in Anil K. Sharma, Raj K. Keservani, Rajesh K. Kesharwani, Nanobiomaterials, 2018
Rahimeh Rasouli, Mahmood Alaei-Beirami, Farzaneh Zaaeri
Carrier mediated transport is categorized in two groups. Facilitated by diffusion, which solute pass moving down concentration gradient (downhill) by conformational conversion of specific membrane protein transporter (solute carrier group either facilitative transporters or secondary active transporters also called coupled transports or co-transports which both of them employ entropic energy) following binding solute to it. For example, glucose and nucleosides, cationic amino acids, small peptides, monocarboxylic acid, glutathione, choline, purine, neutral amino acids or their derivatives like melphalan and L-dopa (Cornford et al., 1992; Ganapathy et al., 2009; Pardridge. 2007,2008; Tsuji. 2005; Tsuji and Tamai. 1999; Wade and Katzman. 1975), and active transport by which transfer solute against concentration gradient (uphill) by hydrolyzing ATP like ABC transporters (i.e., MDR, MRPs 1–6, and BCRP) (Crone, 1965; Egleton and Davis, 2005Zlokovic et al., 1993).
Natural Organic Photosynthetic Solar Energy Transduction
Published in Sun Sam-Shajing, Sariciftci Niyazi Serdar, Organic Photovoltaics, 2017
A remarkable variety of antenna complexes are known, many of which have little or no apparent structural relationship to each other either in terms of protein structure and even in pigment composition. The various types of antennas clearly result from multiple evolutionary innovations. In addition to chlorophylls, antenna pigments include carotenoids. Figure 3.4 shows structures of some of the main classes of photosynthetic antenna complexes. Most of these are distinct molecular complexes that can be separated from the reaction center complexes involved in electron transfer. They can be classified as either integral membrane proteins or peripheral membrane proteins. In some cases, such as Photosystem I from oxygenic photosynthetic organisms, the antenna pigments are an integral part of the core reaction center complex and cannot be separated without destroying the complex.
Recent applications of fluorescent nanodiamonds containing nitrogen-vacancy centers in biosensing
Published in Functional Diamond, 2022
Yuchen Feng, Qi Zhao, Yuxi Shi, Guanyue Gao, Jinfang Zhi
Membrane proteins serve a range of essential tasks for organism survival. Tracking specific protein in real-time, and long-term is of great significance to understand the crucial processes in living cells [72]. According to this, Hsieh et al. [73] developed a membrane protein label by coating FNDs with a thin layer of hyperbranched polyglycerol (HPG) and modifying alkyne on the surface. By using azide-alkyne-based click chemistry, the obtained alkyne-HPGFNDs realized bio-orthogonal labeling and long-term imaging of membrane proteins on live cells (Figure 7(A)). Due to the biological orthogonal reaction, the alkyne-HPGFND can target specific membrane proteins without interfering with the normal physiological process on living cells. This study demonstrated alkyne-HPGFND particles 50 nm that were sufficiently bright to detect single particles by standard fluorescence confocal microscope. Magnetic signal modulation can effectively remove background interference and achieve fluorescence background-free detection, which is suitable for quantitative measurement. Figure 7(B–D) shows the real-time tracking of membrane protein by the fluorescent tag. The authors had also tracked the movement of integrin α5 and β1 in living cells in the short and long term.
Challenges of expressing recombinant human tissue factor as a secreted protein in Pichia pastoris
Published in Preparative Biochemistry & Biotechnology, 2022
Mohammad Jalili-Nik, Mohammad Soukhtanloo, Majid Mojarrad, Mohammad Hadi Sadeghian, Baratali Mashkani
Membrane proteins contain a hydrophobic transmembrane region. It was previously reported that the total hydrophobicity of the signal secretion signal is an important factor influencing protein secretion efficiency Fitzgerald and Glick[16], Peng et al.[23] Sequence analysis of TF using Kyte and Doolittle hydrophobicity plots (ExPasy, http:\\www.expasy.ch\cgi-bin\protscale.pI) revealed that its transmembrane region is highly hydrophobic (Figure 7) Kyte and Doolittle.[24] The hydrophobicity of expressed proteins favors their integration into the lipid bilayer of the intracellular membrane, thereby leading to inefficient translocation and ER export. Thus, the hydrophobicity of the TED region in TF proteins might be contributed to the failure in its proper trafficking and secretion.
Plant pharmacology: Insights into in-planta kinetic and dynamic processes of xenobiotics
Published in Critical Reviews in Environmental Science and Technology, 2022
Tomer Malchi, Sara Eyal, Henryk Czosnek, Moshe Shenker, Benny Chefetz
All pharmacokinetic processes, in animals and plants, depend on the transfer of compounds across membranes by passive diffusion and/or membrane transporters or receptors. Passive diffusion is described by Fick’s law of diffusion (Taiz et al., 2014). Transporter or receptor mediated transport involves specific binding to a membrane protein that enables the compound to cross a membrane. This process may or may not require energy and can drive compound accumulation in compartments on either side of the membrane (Buxton & Benet, 2013). The ability of a compound to passively diffuse across membranes depends on the physicochemical properties of the molecule as described by Lipinski’s “rule of five” (Lipinski, 2004) which predicts membrane crossing if the molecule: (i) is neutrally charged, (ii) has a molecular mass <500 Da, (iii) has less than 5 hydrogen bond donors, (iv) has less than 10 hydrogen bond acceptors, and (v) lipophilicity (log D) between 1 and 5. The kinetics of molecules whose transfer across membranes is mediated by active transport does not follow these rules.