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Nanosensors for Homeland Security
Published in Vinod Kumar Khanna, Nanosensors, 2021
The surface of a 50 nm-thick gold layer on an SPR chip is modified with aminopropyltriethoxysilane, as shown in Figure 12.6, and immersed in an SWCNTs solution to obtain an SWCNTs-SPR chip (Wang et al. 2018). Then, the TNT recognition peptide TNTHCDR3 is non-covalently immobilized on the surface of SWCNTs via π-π interaction. In the TNT recognition peptide, three types of aromatic amino acids actively participate in binding to TNT molecules: tyrosine, tryptophan, and phenylalanine. Preparation and use of TNT recognition peptide-SWCNTs hybrid anchored SPR chip. (Wang et al. 2018.)
Arsenals of Pharmacotherapeutically Active Proteins and Peptides: Old Wine in a New Bottle
Published in Debarshi Kar Mahapatra, Swati Gokul Talele, Tatiana G. Volova, A. K. Haghi, Biologically Active Natural Products, 2020
Aromatic Amino Acids: Amino acids phenylalanine, tryptophan, and tyrosine are aromatic in nature. These amino acids contain a benzene ring. In tryptophan, an indole ring with a propanoic group is found [12, 13].
Structural characterization and in vitro immunogenicity evaluation of amphibian-derived collagen type II from the cartilage of Chinese Giant Salamander (Andrias davidianus)
Published in Journal of Biomaterials Science, Polymer Edition, 2020
Jianlin Luo, Xiaojing Yang, Yu Cao, Guoyong Li, Yonglu Meng, Can Li
The UV absorption data of SCT-II, ASC, and PSC are collected in Figure 3. As SCT-II, ASC, and PSC exhibited a maximum absorption peak at 230 nm, which was related to the groups C = O, –COOH, CONH2 in polypeptide chains, indicating the triple-helical of collagen [17]. The maximum absorption peak was in agreement with the reported cartilage collagen from Siberian sturgeon (230 nm) [15], but lower than whale shark (237–239) [31] and silvertip shark (237–238) [7]. It was reported that the maximum absorption at 280 nm of protein in the near-ultraviolet region is associated with the conjugated double bond of aromatic amino acids (such as tryptophan, tyrosine, and phenylalanine) [36]. In this study, no absorbance at 280 nm was detected in all collagens, which can be explained by the absence of tryptophan and low content of tyrosine and phenylalanine, as shown in Table 2. In addition, the disappeared absorbance peak at 280 nm also revealed high efficacy of non-collagenous protein removal and the appropriately adopted collagen isolation procedure. These results indicated that the ASC and PSC extracted from CGS cartilage had a high purity and maintained the natural triple-helical of collagen.
Size controlled, time-efficient biosynthesis of silver nanoparticles from Pleurotus florida using ultra-violet, visible range, and microwave radiations
Published in Inorganic and Nano-Metal Chemistry, 2020
Gagandeep Kaur, Anu Kalia, Harpreet S. Sodhi
Figure 1(a–c) shows sample tubes containing 1 mM AgNO3 solution after varying durations of reaction time P. florida cell free extract. It can be observed that the color of silver nitrate solution changed from colorless to brown and the color intensity increased with increased duration of incubation time. AgNPs have been well known to exhibit yellowish brown color in water due to surface plasmon vibrations.[35] The absorption spectra of the AgNPs are presented in Figure 2(a–c). All the samples synthesized using visible light showed SPR peaks in the range of 425–500 nm, while also showing sharp peaks between 230 and 280 nm wavelengths. Absorption at 280 nm indicated the presence of aromatic amino acids like tyrosine, tryptophan, or phenylalanine residues in the proteins present in mushroom extracts, which are known to interact with silver ions. Anthraquinones show intense quinonoid bands in a range from 260 to 290 nm and hydroxyl anthraquinones show an absorption band between 220 and 240 nm.[36,37] The sharpness of the peak at 450–500 nm varied with the concentration of AgNPs. AgNPs exhibit SPR peaks ranging from 400 to 500 nm wavelength.[38]
New mechanistic insights into the Claisen rearrangement of chorismate – a Unified Reaction Valley Approach study
Published in Molecular Physics, 2019
Marek Freindorf, Yunwen Tao, Daniel Sethio, Dieter Cremer, Elfi Kraka
The Bacillus subtilis chorismate mutase (BsCM) catalysed intramolecular Claisen rearrangement of chorismate (1) to prephenate (3) (see Figure 1) is one of the few pericyclic processes in biology [1–3]. It is an important part of the shikimate pathway controlling the biosynthesis of aromatic amino acids (e.g. tryptophan, tyrosine, and phenylalanine) in the cells of fungi, bacteria and higher plants [4–7], and as such has become one of the most studied enzyme reactions [8–32]. The theoretical interest in the BsCM-catalysed chorismate rearrangement was triggered by the fact that (i) the substrate does not covalently bind to the active site [33–35] so that the system can be easily separated into a QM region (the substrate) and an MM region (the enzyme); and (ii) the wealth of experimental data available to cross-check the reliability of the computational studies [2, 36–45].