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Single-Molecule Manipulation by Magnetic Tweezers
Published in Shuo Huang, Single-Molecule Tools for Bioanalysis, 2022
The free energy of protein folding determines its structural stability, while the rates of folding/unfolding transitions reflect the pathway and the energy barrier of the transitions. Magnetic tweezers, which apply a well-controlled force to the protein termini, are able to directly monitor the folding and unfolding dynamics of a single protein through its extension time courses. The streptococcal B1 immunoglobulin-binding domain of protein G (GB1), which possesses an exceptional elastomeric feature and is mechanically stable under tension, was tentatively selected as the model protein for this study. Its polyprotein form, consisting of eight identical tandem repeats of GB1 domains and desired tethers, was engineered, and we demonstrate in detail how the target protein is conjugated and how its mechanical property is measured.
Helical Symmetry
Published in Mihai V. Putz, New Frontiers in Nanochemistry, 2020
The biochemical process through a protein structure attains its functional shape or conformation is called protein folding (Dill et al., 2012). The most plausible explanation is the distance-dependence behavior of the conduction, where in the case of shorter homogeneous base sequences the charge transport would be a coherent process, while at longer distances over the aperiodic base sequences the thermally induced hopping is more likely (Giese et al., 2001; Genereux et al., 2011). On the other hand, this special electron structure of the DNA chain could play an important role in detecting DNA damages (Sontz et al., 2012) or could be used as a very efficient spin filter at room temperature for spintronic applications (Göhler et al., 2011). This process is mainly guided by hydrophobic interactions, the formation of intramolecular hydrogen bonds, and van der Waals forces, and it is opposed by conformational entropy (Miller et al., 2014). As a result of this protein folding the most abundant class of secondary structures is the helical configuration, especially the so-called α-helix. The helical structure of the polypeptide chains was for the first time experimentally observed by Pauling et al. (1951), and different forms of the helical configuration can be seen in Figure 21.4.
Safety Guidelines for Electromagnetic Field Exposure and Mobile Towers
Published in Jitendra Behari, Radio Frequency and Microwave Effects on Biological Tissues, 2019
Buchner and Eger (2011) exposed human fibroblasts to modulated GSM 1800 MHz at 2 W/kg. While acute studies (within 2 hours) did not significantly alter the proteome, an 8-hour exposure caused a significant and reproducible increase in protein synthesis. Most of the proteins are found to cause a significant and reproducible increase in protein synthesis. Most of the proteins found to be induced were chaperones,which are mediators of protein folding. Heat-induced proteome alterations detectable with used proteome methodology would require heating greater than 1°C. GSM-induced heating was less than 0.15°C and hence excluded. These data further supported the notion that the exposure time seems to be a critical factor.
Technology fitness landscape for design innovation: a deep neural embedding approach based on patent data
Published in Journal of Engineering Design, 2022
Prior studies have pointed out that technological improvement or novelty arises from the recombination or synthesis of existing technologies (He and Luo 2017; He et al. 2019), which, in our cases, can be viewed as such mutations of the technological genotype. Following the analogy framework, the latest innovations in autonomous vehicles have changed the genotype of automobiles and increased the values of automobiles by fusing artificial intelligence to assist or automate driving and battery-powered electric powertrain to replace combustion engines. Similarly, recent progress on the structure prediction component of the ‘protein folding problem’ achieved by DeepMind also presents the power of incorporating deep learning techniques (AlphaFold) into traditional biological domains (Jumper, Evans, and Pritzel 2021). In the past, it would take biologists six months to predict a protein structure, while now it takes only a couple of minutes using AI. Speaking in biological evolution terms, these domains’ genotypes have been mutated with increased fitness in the total technological space. The new genotype is positioned closer to the global peak in the technology fitness landscape.
Exploration of ligand-induced protein conformational alteration, aggregate formation, and its inhibition: A biophysical insight
Published in Preparative Biochemistry and Biotechnology, 2018
Saima Nusrat, Rizwan Hasan Khan
Protein folding is a biophysical process where protein folds into its specific three-dimensional functional state from its random coil or other structural conformation.[10] The sequence of amino acid residues provides the knowledge regarding its native conformation,[11] and the right sequence is crucial for the functional activity of proteins. The inaccurate folding of native protein causes loss in the functional activity and misfolding, leading to the formation of toxic complexes,[5] as observed in case of aggregation-linked diseases.[12,13] The deposition and accumulation of misfolded proteins occur in the form of amorphous or amyloid fibrils in different body parts of human beings.[1,14,15]
Chaperone-assisted soluble expression and characterization of chitinase chiZJ408 in Escherichia coli BL21 and the chitin degradation by recombinant enzyme
Published in Preparative Biochemistry & Biotechnology, 2022
Ping Yu, Xinxin Wang, Jian Ma, Qili Zhang, Qingwei Chen
Because of its stable genetic traits, short culture period, and good stability of the expressed product, Escherichia coli BL21 is currently considered the most widely used exogenous protein expression host. However, the inclusion body is prone to form when foreign genes are expressed in E. coli, because the nascent peptide cannot form disulfide bonds at the correct positions. Molecular chaperone plays an important role in the process of protein folding and assembly, which can help the protein to fold correctly, improve the soluble expression of protein and reduce the formation of inclusion body.[14] GroELS is an important molecular chaperone in E. coli. It consists of 60 kDa GroEL and its 10 kDa auxiliary protein GroES.[15,16] Studies have shown that these two proteins are necessary for the low-temperature growth of E. coli cells and play an important role in promoting protein folding and preventing erroneous aggregation in the cellular environment.[17] GroELS participates in protein folding and transmembrane transport, provides energy for cells by catalyzing the hydrolysis of ATP, maintains the stability of protein during the folding process, and helps foreign proteins form the correct structure when expressed.[18,19] However, there are few reports about its auxiliary folding of high molecular weight chitinase, most of which form an inclusion body when expressed in E. coli.[5,20,21] Therefore, it is interesting to investigate if the co-expression of high molecular weight chitinase and molecular chaperone GroELS can promote the correct folding of chitinase and increase its soluble expression in E. coli.