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Protein Adhesives
Published in A. Pizzi, K. L. Mittal, Handbook of Adhesive Technology, 2017
Charles R. Frihart, Linda F. Lorenz
Most proteins, including those used in adhesives, are globular proteins that have enough hydrophobic portions or weakly hydrophilic portions to cause the protein to fold inward in an aqueous environment (Figure 5.3). During this hydrophobic collapse, intramolecular association of hydrophobic amino acids moves them mainly to the inside of the globular structure and the polar amino acids preferentially to the outside. However, the primary and secondary structures limit the ability of particular amino acids to move to these separate regions. The polar groups on the inside of the globule are stabilized by associating with other polar groups on the chain. These types of interactions include not only hydrogen bonds, but also acid–base salt bridges and disulfides from the thiol groups. Some of the hydrophobic amino acids end up on the outside of the structure. This folding of the protein is referred to as its tertiary structure.
Fundamentals of biology and thermodynamics
Published in Mohammad E. Khosroshahi, Applications of Biophotonics and Nanobiomaterials in Biomedical Engineering, 2017
The native conformation of protein has a 3-D structure. Primary structure is the linear sequence of amino acids along the polypeptide backbone. Secondary structure is the folding of certain regions of the protein into helical arrays. tertiary structure is the single polypeptide chain. Quarternary structure is the relative arrangement of polypeptide chains in higher order aggregates. Denaturation is a process in which proteins or nucleic acids lose the quaternary structure, tertiary structure, and secondary structure which is present in their native state, by application of some external stress or compound such as a strong acid or base, a concentrated inorganic salt, an organic solvent (e.g., alcohol or chloroform), radiation, or heat. If proteins in a living cell are denatured, this results in disruption of cell activity, and possibly cell death. Denatured proteins can exhibit a wide range of characteristics, from conformational change and loss of solubility to aggregation due to the exposure of hydrophobic groups. It should be noted that when proteins are coagulated they tend to clump into a semi-soft, solid-like substance. A chemical change has taken place because a new substance is produced.
Elements of Polymer Science
Published in E. Desmond Goddard, James V. Gruber, Principles of Polymer Science and Technology in Cosmetics and Personal Care, 1999
E. Desmond Goddard, James V. Gruber
The shape of protein molecules is not given completely by their secondary structure. Sections of peptide chains may be linked chemically through sulfur bonds of cystein groups, as in the case of keratins, or by salt bridges between carboxyl groups and ammonium groups, such as the glutamic acid-lysine links present in α-keratin (59). This overall three-dimensional structure of a protein molecule is known as its tertiary structure. In addition to tertiary structure, a protein may exhibit a quaternary structure that originates from associations of several proteins or of proteins and nonprotein sustances. Rheology and Mechanical Properties of Polymers (61,62)
Green synthesis of silver nanoparticles using Caesalpinia bonducella leaf extract: characterization and evaluation of in vitro anti-inflammatory and anti-cancer activities
Published in Inorganic and Nano-Metal Chemistry, 2022
In the present study, the anti-inflammatory activity of silver nanoparticles was assessed by protein denaturation method. Protein denaturation is a process in which a protein loses its biological function due to the destruction of its secondary and tertiary structures. This may be brought about by various factors such as heat, electrolytes, pH fluctuation, or alcohol, which produce alterations in the solubility of proteins such as albumins and globulins.[51] Inflammation and protein denaturation are closely related. Protein denaturation leads to inflammation because it permits the generation of autoantigens, which are responsible for inflammation in rheumatic diseases.[52] In the present work, different concentrations of aqueous leaf extract and silver nanoparticles were subjected to evaluation of anti-inflammatory activity which was compared against the standard reference drug diclofenac sodium. A significant difference was observed between the inhibition of thermally induced protein denaturation by the leaf extract and that by the AgNPs when compared against the standard drug (100 µg/mL). The inhibitory effect of silver nanoparticles 85.67 ± 1.63% was comparable to that of diclofenac sodium 91.78 ± 1.46% while the extract showed 20.3 ± 1.45% lesser inhibitory potential compared to both the standard drug and the nanoparticles (Table 1). Our results are in agreement with the reports presented by previous workers where synthesized silver nanoparticles using Calophyllum tomentosum leaf extract and found the anti-inflammatory activity of the nanoparticles to be around 84.64 ± 1.4%.[53]
Fractal and mathematical morphology in intricate comparison between tertiary protein structures
Published in Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, 2018
Ranjeet Kumar Rout, Pabitra Pal Choudhury, Santi Prasad Maity, B. S. Daya Sagar, Sk. Sarif Hassan
The Protein Data Bank PDB (Berman et al. 2000) (http://www.rcsb.org/pdb/home/home.do) is the largest and most commonly used repository; from which information regarding proteins is utilised. The most popular techniques in obtaining protein tertiary structure include the X-ray crystallography and nuclear magnetic resonance (Robillard et al. 1976; Billeter 1992; Drenth 1999). From the PDB (Berman et al. 2000) database, three proteins viz. 2LEP, 3V2J and 3V2M in the standard .pdb format are collected and are shown in Figure 1. The tertiary structure is represented in a standard Cartesian coordinates of the atoms presented in the protein 2LEP is shown in Figure 2.
A comprehensive review on stability of therapeutic proteins treated by freeze-drying: induced stresses and stabilization mechanisms involved in processing
Published in Drying Technology, 2022
Zhe Wang, Linlin Li, Guangyue Ren, Xu Duan, Jingfang Guo, Wenchao Liu, Yuan Ang, Lewen Zhu, Xing Ren
The function of therapeutic proteins depends on their spatial structure, including primary structure, secondary structure, and tertiary structure. Changes in protein structure can lead to the loss of therapeutic protein activity. Therefore, the structural changes during the freeze-drying of therapeutic proteins are also a hot research topic. Studies had shown that freeze-drying can cause the loss of protein secondary structure. In the study of Xu et al,[78] it was found that freeze-drying caused the loss of the main secondary structure of RhGH. The results showed that there was a significant correlation between the retention of secondary structure and the degradation process of the protein during storage at 40 °C. The higher the retention of the secondary structure, the lower the rate constant of oxidation and aggregation. It was found that trehalose and sucrose can effectively retain the natural structure of protein and improve its storage stability. Despite this, it still cannot visually show the effect of freeze-drying on the conformation of therapeutic proteins. Taschner et al [87] investigated a case where the anti-idiotypic antibody MMA 383 substantially lost its immunogenicity in vivo when the protein was not degraded. The images of its Fab and Fc moieties were obtained by scanning transmission electron microscopy. The results showed that the non-lyophilized antibody had a wider shape than the recombinant lyophilized antibody, and the angle of the Fab moiety changed more, indicating greater flexibility, which indicated that lyophilization reduces the overall flexibility of the antibody. These changes may be related to the decreased immunogenicity of recombinant freeze-dried antibodies in vivo.