Structure and Functions of Amino Acids and Proteins
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Side-Chain Liquid Crystal Polymers (SCLCP): Methods and Materials. an Overview
Materials 2009, 2, 95-128; doi:10.3390/ma2010095 OPEN ACCESS materials ISSN 1996-1944 www.mdpi.com/journal/materials Review Side-chain Liquid Crystal Polymers (SCLCP): Methods and Materials. An Overview Tomasz Ganicz * and Włodzimierz Stańczyk Centre of Molecular and Macromolecular Studies, Polish Academy of Science, Sienkiewicza 112, 90- 363 Łódź, Poland; E-Mail: [email protected] * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel. +48-42-684-71-13; Fax: +48-42-684-71-26 Received: 5 February 2009; in revised form: 3 March 2009 / Accepted: 9 March 2009 / Published: 11 March 2009 Abstract: This review focuses on recent developments in the chemistry of side chain liquid crystal polymers. It concentrates on current trends in synthetic methods and novel, well defined structures, supramolecular arrangements, properties, and applications. The review covers literature published in this century, apart from some areas, such as dendritic and elastomeric systems, which have been recently reviewed. Keywords: Liquid crystals, side chain polymers, polymer modification, polymer synthesis, self-assembly. 1. Introduction Over thirty years ago the work of Finkelmann and Ringsdorf [1,2] gave important momentum to synthesis of side chain liquid crystal polymers (SCLCPs), materials which combine the anisotropy of liquid crystalline mesogens with the mechanical properties of polymers. Although there were some earlier attempts [2], their approach of decoupling the motions of a polymer main chain from a mesogen, thus allowed side chain moieties to build up long range ordering (Figure 1). They were able to synthesize polymers with nematic, smectic and cholesteric phases via free radical polymerization of methacryloyl type monomers [3]. -
The Role of Side-Chain Branch Position on Thermal Property of Poly-3-Alkylthiophenes
Polymer Chemistry The Role of Side-chain Branch Position on Thermal Property of Poly-3-alkylthiophenes Journal: Polymer Chemistry Manuscript ID PY-ART-07-2019-001026.R2 Article Type: Paper Date Submitted by the 02-Oct-2019 Author: Complete List of Authors: Gu, Xiaodan; University of Southern Mississippi, School of Polymer Science and Engineering Cao, Zhiqiang; University of Southern Mississippi, School of Polymer Science and Engineering Galuska, Luke; University of Southern Mississippi, School of Polymer Science and Engineering Qian, Zhiyuan; University of Southern Mississippi, School of Polymer Science and Engineering Zhang, Song; University of Southern Mississippi, School of Polymer Science and Engineering Huang, Lifeng; University of Southern Mississippi, School of Polymers and High Performance Materials Prine, Nathaniel; University of Southern Mississippi, School of Polymer Science and Engineering Li, Tianyu; Oak Ridge National Laboratory; University of Tennessee Knoxville He, Youjun; Oak Ridge National Laboratory Hong, Kunlun; Oak Ridge National Laboratory, Center for Nanophase Materials Science; Oak Ridge National Laboratory, Center for Nanophase Materials Science Page 1 of 13 PleasePolymer do not Chemistryadjust margins ARTICLE The Role of Side-chain Branch Position on Thermal Property of Poly-3-alkylthiophenes Received 00th January 20xx, a a a a a a Accepted 00th January 20xx Zhiqiang Cao, Luke Galuska, Zhiyuan Qian, Song Zhang, Lifeng Huang, Nathaniel Prine, Tianyu Li,b, c Youjun He,b Kunlun Hong,*b, c and Xiaodan Gu*a DOI: 10.1039/x0xx00000x Thermomechanical properties of conjugated polymers (CPs) are greatly influenced by both their microstructures and backbone structures. In the present work, to investigate the effect of side-chain branch position on the backbone’s mobility and molecular packing structure, four poly (3-alkylthiophene-2, 5-diyl) derivatives (P3ATs) with different side chains, either branched and linear, were synthesized by a quasi-living Kumada catalyst transfer polymerization (KCTP) method. -
Al Exposure Increases Proline Levels by Different Pathways in An
www.nature.com/scientificreports OPEN Al exposure increases proline levels by diferent pathways in an Al‑sensitive and an Al‑tolerant rye genotype Alexandra de Sousa1,2, Hamada AbdElgawad2,4, Fernanda Fidalgo1, Jorge Teixeira1, Manuela Matos3, Badreldin A. Hamed4, Samy Selim5, Wael N. Hozzein6, Gerrit T. S. Beemster2 & Han Asard2* Aluminium (Al) toxicity limits crop productivity, particularly at low soil pH. Proline (Pro) plays a role in protecting plants against various abiotic stresses. Using the relatively Al‑tolerant cereal rye (Secale cereale L.), we evaluated Pro metabolism in roots and shoots of two genotypes difering in Al tolerance, var. RioDeva (sensitive) and var. Beira (tolerant). Most enzyme activities and metabolites of Pro biosynthesis were analysed. Al induced increases in Pro levels in each genotype, but the mechanisms were diferent and were also diferent between roots and shoots. The Al‑tolerant genotype accumulated highest Pro levels and this stronger increase was ascribed to simultaneous activation of the ornithine (Orn)‑biosynthetic pathway and decrease in Pro oxidation. The Orn pathway was particularly enhanced in roots. Nitrate reductase (NR) activity, N levels, and N/C ratios demonstrate that N‑metabolism is less inhibited in the Al‑tolerant line. The correlation between Pro changes and diferences in Al‑sensitivity between these two genotypes, supports a role for Pro in Al tolerance. Our results suggest that diferential responses in Pro biosynthesis may be linked to N‑availability. Understanding the role of Pro in diferences between genotypes in stress responses, could be valuable in plant selection and breeding for Al resistance. Proline (Pro) is involved in a wide range of plant physiological and developmental processes1. -
Collagen and Elastin Fibres
J Clin Pathol: first published as 10.1136/jcp.s3-12.1.49 on 1 January 1978. Downloaded from J. clin. Path., 31, Suppl. (Roy. Coll. Path.), 12, 49-58 Collagen and elastin fibres A. J. BAILEY From the Agricultural Research Council, Meat Research Institute, Langford, Bristol Although an understanding of the intracellular native collagen was generated from type I pro- biosynthesis of both collagen and elastin is of collagen. Whether this means that the two pro- considerable importance it is the subsequent extra- collagens are converted by different enzyme systems cellular changes involving fibrogenesis and cross- and the type III enzyme was deficient in these linking that ensure that these proteins ultimately fibroblast cultures, or that the processing of pro become the major supporting tissues of the body. type III is extremely slow, is not known. The latter This paper summarises the formation and stability proposal is consistent with the higher proportion of collagen and elastin fibres. of soluble pro type III extractable from tissue (Lenaers and Lapiere, 1975; Timpl et al., 1975). Collagen Basement membrane collagens, on the other hand, do not form fibres and this property may be The non-helical regions at the ends of the triple due to the retention of the non-helical extension helix of procollagen probably provide a number of peptides (Kefalides, 1973). In-vivo biosynthetic different intracellular functions-that is, initiating studies showing the absence of any extension peptide rapid formation of the triple helix; inhibiting intra- removal support this (Minor et al., 1976), but other cellular fibrillogenesis; and facilitating transmem- workers have reported that there is some cleavage brane movement. -
Selenocysteine, Pyrrolysine, and the Unique Energy Metabolism of Methanogenic Archaea
Hindawi Publishing Corporation Archaea Volume 2010, Article ID 453642, 14 pages doi:10.1155/2010/453642 Review Article Selenocysteine, Pyrrolysine, and the Unique Energy Metabolism of Methanogenic Archaea Michael Rother1 and Joseph A. Krzycki2 1 Institut fur¨ Molekulare Biowissenschaften, Molekulare Mikrobiologie & Bioenergetik, Johann Wolfgang Goethe-Universitat,¨ Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany 2 Department of Microbiology, The Ohio State University, 376 Biological Sciences Building 484 West 12th Avenue Columbus, OH 43210-1292, USA Correspondence should be addressed to Michael Rother, [email protected] andJosephA.Krzycki,[email protected] Received 15 June 2010; Accepted 13 July 2010 Academic Editor: Jerry Eichler Copyright © 2010 M. Rother and J. A. Krzycki. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Methanogenic archaea are a group of strictly anaerobic microorganisms characterized by their strict dependence on the process of methanogenesis for energy conservation. Among the archaea, they are also the only known group synthesizing proteins containing selenocysteine or pyrrolysine. All but one of the known archaeal pyrrolysine-containing and all but two of the confirmed archaeal selenocysteine-containing protein are involved in methanogenesis. Synthesis of these proteins proceeds through suppression of translational stop codons but otherwise the two systems are fundamentally different. This paper highlights these differences and summarizes the recent developments in selenocysteine- and pyrrolysine-related research on archaea and aims to put this knowledge into the context of their unique energy metabolism. 1. Introduction found to correspond to pyrrolysine in the crystal structure [9, 10] and have its own tRNA [11]. -
Effects of Single Amino Acid Deficiency on Mrna Translation Are Markedly
www.nature.com/scientificreports OPEN Efects of single amino acid defciency on mRNA translation are markedly diferent for methionine Received: 12 December 2016 Accepted: 4 May 2018 versus leucine Published: xx xx xxxx Kevin M. Mazor, Leiming Dong, Yuanhui Mao, Robert V. Swanda, Shu-Bing Qian & Martha H. Stipanuk Although amino acids are known regulators of translation, the unique contributions of specifc amino acids are not well understood. We compared efects of culturing HEK293T cells in medium lacking either leucine, methionine, histidine, or arginine on eIF2 and 4EBP1 phosphorylation and measures of mRNA translation. Methionine starvation caused the most drastic decrease in translation as assessed by polysome formation, ribosome profling, and a measure of protein synthesis (puromycin-labeled polypeptides) but had no signifcant efect on eIF2 phosphorylation, 4EBP1 hyperphosphorylation or 4EBP1 binding to eIF4E. Leucine starvation suppressed polysome formation and was the only tested condition that caused a signifcant decrease in 4EBP1 phosphorylation or increase in 4EBP1 binding to eIF4E, but efects of leucine starvation were not replicated by overexpressing nonphosphorylatable 4EBP1. This suggests the binding of 4EBP1 to eIF4E may not by itself explain the suppression of mRNA translation under conditions of leucine starvation. Ribosome profling suggested that leucine deprivation may primarily inhibit ribosome loading, whereas methionine deprivation may primarily impair start site recognition. These data underscore our lack of a full -
01. Amino Acids
01. Amino Acids 1 Biomolecules • Protein • Carbohydrate • Nucleic acid • Lipid 2 peptide polypeptide protein di-, tri-, oligo- 3 4 fibrous proteins proteins globular proteins 5 Figure 4.1 Anatomy of an amino acid. Except for proline and its derivatives, all of the amino acids commonly found in proteins possess this type of structure. 6 Glycine (Gly, G) Alanine (Ala, A) Valine (Val, V)* Leucine (Leu, L)* Isoleucine (Ile. I)* 7 Serine (Ser, S) Threonine (Thr, T)* Cysteine (Cys, C)cystine Methionine (Met, M)* 8 Aspartate (Asp, D) Glutamate (Glu, E) Asparagine (Asn, N) Glutamine (Gln, Q) 9 Lysine (Lys, K)* Arginine (Arg, R)* 10 Phenylalanine (Phe, F)* Tyrosine (Tyr, Y) Histidine (His, H)* Tryptophan (Trp, W)* 11 Proline (Pro, P) 12 Hydrophobic (A, G, I, L, F, V, P) Hydrophilic (D, E, R, S, T, C, N, Q, H) Amphipathic (K, M, W, Y) 13 Essential amino acids: V, L, I, T, M, K, R, F, H, W 14 Several Amino Acids Occur Rarely in Proteins We'll see some of these in later chapters • Selenocysteine in many organisms • Pyrrolysine in several archaeal species • Hydroxylysine, hydroxyproline - collagen • Carboxyglutamate - blood-clotting proteins • Pyroglutamate – in bacteriorhodopsin • GABA, epinephrine, histamine, serotonin act as neurotransmitters and hormones • Phosphorylated amino acids – a signaling device Several Amino Acids Occur Rarely in Proteins Several Amino Acids Occur Rarely in Proteins Figure 4.4 (b) Some amino acids are less common, but nevertheless found in certain proteins. Hydroxylysine and hydroxyproline are found in connective-tissue proteins; carboxy- glutamate is found in blood-clotting proteins; pyroglutamate is found in bacteriorhodopsin (see Chapter 9). -
Selenocysteine, Identified As the Penultimate C-Terminal Residue in Human T-Cell Thioredoxin Reductase, Corresponds to TGA in the Human Placental Gene" (1996)
University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Vadim Gladyshev Publications Biochemistry, Department of June 1996 Selenocysteine, identified as the penultimate C-terminal esiduer in human T-cell thioredoxin reductase, corresponds to TGA in the human placental gene Vadim Gladyshev University of Nebraska-Lincoln, [email protected] Kuan-Teh Jeang National Institutes of Health, Bethesda, MD Thressa C. Stadtman National Institutes of Health, Bethesda, MD Follow this and additional works at: https://digitalcommons.unl.edu/biochemgladyshev Part of the Biochemistry, Biophysics, and Structural Biology Commons Gladyshev, Vadim; Jeang, Kuan-Teh; and Stadtman, Thressa C., "Selenocysteine, identified as the penultimate C-terminal residue in human T-cell thioredoxin reductase, corresponds to TGA in the human placental gene" (1996). Vadim Gladyshev Publications. 23. https://digitalcommons.unl.edu/biochemgladyshev/23 This Article is brought to you for free and open access by the Biochemistry, Department of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Vadim Gladyshev Publications by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Proc. Natl. Acad. Sci. USA Vol. 93, 6146-6151, June 1996 Biochemistrypp. Selenocysteine, identified as the penultimate C-terminal residue in human T-cell thioredoxin reductase, corresponds to TGA in the human placental gene (selenium/thioredoxin reductase/TGA/selenocysteine) VADIM N. GLADYSHEV*, KUAN-TEH JEANGt, AND THRESSA C. STADTMAN*t *Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, and tLaboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892 Contributed by Thressa C. Stadtman, February 27, 1996 ABSTRACT The possible relationship of selenium to im- peroxidase family (8). -
Collagen Structural Microheterogeneity and a Possible Role for Glycosylated Hydroxylysine in Type 1 Collagen
Proc. NatL Acad. Sci. USA Vol. 79, pp. 7684-7688, December 1982 Biochemistry Collagen structural microheterogeneity and a possible role for glycosylated hydroxylysine in type 1 collagen (nonreducible stable crosslinks/hydroxyaldolhistidine/specific cleavage/molecular location) MITSUO YAMAUCHI*t, CLAUDIA NOYES*t, YOSHINORI KUBOKI*t, AND GERALD L. MECHANIC*§¶ *Dental Research Center, §Department of Biochemistry and Nutrition, and tDepartment of Medicine, University of North Carolina, Chapel Hill, North Carolina 27514 Communicated by. Ernest L. Eliel, September 20, 1982 ABSTRACT A three-chained peptide from type I collagen, and Mechanic (8) that dehydro-HisOHMerDes, which was crosslinked by hydroxyaldolhistidine, has been isolated from a thought to be artifactual (9, 10) is a true crosslink in collagen tryptic digest of5 M guanidine HCI-insoluble bovine skin collagen fibrils. Bernstein and Mechanic found that one HisOHMerDes (a small but as yet unknown percentage of the total collagen in crosslink was present per molecule of collagen in freshly re- whole skin). Os04/NaIO4 specifically cleaved the crosslink at its constituted soluble collagen fibrils. double bond into a two-chained crosslink peptide and a single pep- Histidine was also found to be a constituent of the stable tide. The sequence of the two-chained peptide containing the bi- nonreducible trifunctional crosslink hydroxyaldolhistidine functional crosslink was determined after amino acid analysis of (OHAlHis), whose structure was elucidated by PMR and mass the separated peptides. The crosslink consists of an aldehyde de- spectrometry rived from hydroxylysine-87 in the aldehyde-containing cyanogen (11). OHAIHis was isolated from bovine skin col- bromide fragment alCB5ald and an aldehyde derived from the lagen. -
Amino Acid Recognition by Aminoacyl-Trna Synthetases
www.nature.com/scientificreports OPEN The structural basis of the genetic code: amino acid recognition by aminoacyl‑tRNA synthetases Florian Kaiser1,2,4*, Sarah Krautwurst3,4, Sebastian Salentin1, V. Joachim Haupt1,2, Christoph Leberecht3, Sebastian Bittrich3, Dirk Labudde3 & Michael Schroeder1 Storage and directed transfer of information is the key requirement for the development of life. Yet any information stored on our genes is useless without its correct interpretation. The genetic code defnes the rule set to decode this information. Aminoacyl-tRNA synthetases are at the heart of this process. We extensively characterize how these enzymes distinguish all natural amino acids based on the computational analysis of crystallographic structure data. The results of this meta-analysis show that the correct read-out of genetic information is a delicate interplay between the composition of the binding site, non-covalent interactions, error correction mechanisms, and steric efects. One of the most profound open questions in biology is how the genetic code was established. While proteins are encoded by nucleic acid blueprints, decoding this information in turn requires proteins. Te emergence of this self-referencing system poses a chicken-or-egg dilemma and its origin is still heavily debated 1,2. Aminoacyl-tRNA synthetases (aaRSs) implement the correct assignment of amino acids to their codons and are thus inherently connected to the emergence of genetic coding. Tese enzymes link tRNA molecules with their amino acid cargo and are consequently vital for protein biosynthesis. Beside the correct recognition of tRNA features3, highly specifc non-covalent interactions in the binding sites of aaRSs are required to correctly detect the designated amino acid4–7 and to prevent errors in biosynthesis5,8. -
Electrochemical Studies of Dl-Leucine, L-Proline and L
ELECTROCHEMICAL STUDIES OF DL -LEUCINE, 60 L-PROLINE AND L-TRYPTOPHAN AND THEIR INTERACTION WITH COPPER AND IRON 30 c b A) M. A. Jabbar, R. J. Mannan, S. Salauddin and B. µ a Rashid 0 Department of Chemistry, University of Dhaka, ( Current Dhaka-1000, Bangladesh -30 Introduction -60 In vitro study of the charge transfer reactions coupled -800 -400 0 400 800 with chemical reactions can give important indication of Potential vs. Ag/AgCl (mV) about actual biological processes occurring in human Fig.1. Comparison of the cyclic voltammogram of system. Understanding of such charge-transfer 5.0mM (a) DL -Leucine, (b) Cu-DL -Leucine ion and mechanism will help to determine the effectiveness of (c) [Fe-DL -Leucine] in 0.1M KCl solution at a Pt- nutrition, metabolism and treatment of various biological button electrode. Scan rates 50 mV/s. disorders. In the previous research, the redox behaviour of 40 various amino acids and biochemically important compounds and their charge transfer reaction and their b interaction of metal ions were studied [1,2]. In the present 20 ) a c research, the redox behavior and the charge transfer µΑ kinetics of DL -Leucine, L-Proline and L-Tryptophan in 0 the presence and absence of copper and iron will be investigated. Current ( -20 Experimental A computerized electrochemistry system developed by -40 -800 -400 0 400 800 Advanced Analytics, Virginia, USA, (Model-2040) Potential vs. Ag/AgCl (mV) consisting of three electrodes micro-cell with a saturated Ag/AgCl reference, a Pt-wire auxiliary and a pretreated Fig.2 . Comparison of the cyclic voltammogram of Pt-button working electrode is employed to investigate 5.0mM (a) L-Proline, (b) Cu-L-Proline and (c) Fe-L- Proline in 0.1M KCl solution at a Pt-button different amino acids and metal-amino acid systems. -
Convenient Preparation of Poly(L-Histidine) by the Direct Polymerization of L-Histidine Or Nim Benzyl-L-Histidine with Diphenylphosphoryl Azide
Polymer Journal, Vol. 13, No. 12, pp 1151-1154 (1981) SHORT COMMUNICATION Convenient Preparation of Poly(L-histidine) by the Direct Polymerization of L-Histidine or Nim_Benzyl-L-histidine with Diphenylphosphoryl Azide Takumi NARUSE, Bun-ichiro NAKAJIMA, Akihiro TSUTSUMI, and Norio NISHI Department of Polymer Science, Faculty of Science, Hokkaido University, Nishi 8-chome, Kita 10-jo, Kita-ku, Sapporo 060, Japan. (Received August 14, 1981) KEY WORDS Polymerization I Diphenylphosphoryl Azide (DPPA) I L- Histidine I N'm-Benzyl-L-histidine I Poly(L-histidine) I Poly(N'm-benzyl-L histidine) I IR Spectrum I 13C NMR Spectrum I Intrinsic Viscosity I Poly(L-histidine) is a very interesting poly(a histidine) by the polymerization of L-histidine with amino acid) as a synthetic functional polymer or as iodine-phosphonic acid esters was unsuccessful. The a model for the functional biopolymer such as simplification of the synthetic route for poly(L enzymes. It is known, however, that poly(L histidine) is still necessary. histidine) can not be prepared by the Fuchs Diphenylphosphoryl azide (DPPA) has been used Farthing method 1 which is very popular for prepar as a convenient reagent for racemization-free pep ing poly(a-amino acid)s. A synthetic route with tide synthesis, since it was synthesized by Shioiri et several steps involving the synthesis of NCA (a a!. in 1972.6 Recently, we reported that this reagent amino acid N-carboxyanhydride) by the rather can also be used successfully for the polymerization classical Leuchs method/ have been used for the of amino acids or peptides.