scholarly journals Allergenicity of Deamidated and/or Peptide-Bond-Hydrolyzed Wheat Gliadin by Transdermal Administration

Foods ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 635
Author(s):  
Ryosuke Abe ◽  
Narumi Matsukaze ◽  
Hayato Kobayashi ◽  
Yusuke Yamaguchi ◽  
Harumi Uto-Kondo ◽  
...  
Keyword(s):  
Main Chain ◽  
Peptide Bond ◽  
Side Chain ◽  
Severe Allergic Reaction ◽  
Wheat Protein ◽  
Immediate Hypersensitivity ◽  
Transdermal Administration ◽  
Amide Bonds ◽  
Wheat Gliadin ◽  
Wheat Products

Hydrochloric acid (HCl)-treated wheat protein (HWP) is widely used in various products, including foods, cosmetics and shampoos. Recently, immediate hypersensitivity towards facial soap containing HWP has been reported. HCl treatment of protein causes hydrolysis not only of main-chain amide bonds (peptide-bond hydrolysis) but also of side-chain ones (deamidation). We have already reported that gliadin, the main allergen in wheat, reduces allergenicity and increases digestibility by deamidation, indicating that deamidation and peptide-bond hydrolysis are effective to reduce the allergenicity of wheat protein. However, transdermally administered HWP is assumed to induce sensitization to orally administered wheat protein even in those who have been taking wheat products daily before sensitization. The present study was conducted to examine which structural change is responsible for the induction of cutaneous sensitization by comparing the allergenicity of deamidated and/or peptide-bond-hydrolyzed wheat gliadin. Because we have developed a deamidation method without causing peptide-bond hydrolysis, only deamidated wheat gliadin is available. Therefore, after deamidated-only, hydrolyzed-only, and deamidated and hydrolyzed gliadins were transdermally administered to mice for several weeks, the corresponding gliadin was intraperitoneally administered and allergenicity was evaluated. Transdermal administration of deamidated and hydrolyzed gliadin induced severe allergic reaction, while that of deamidated-only and hydrolyzed-only gliadin showed almost no allergic response. This result indicates that both deamidation and peptide-bond hydrolysis are necessary to increase the allergenic potency of transdermally administered wheat gliadin.

scholarly journals Substrate Scope for Human Histone Lysine Acetyltransferase KAT8

2021 ◽  
Vol 22 (2) ◽  
pp. 846
Author(s):  
Giordano Proietti ◽  
Yali Wang ◽  
Chiara Punzo ◽  
Jasmin Mecinović
Keyword(s):  
Main Chain ◽  
Coenzyme A ◽  
Side Chain ◽  
Histone H4 ◽  
Chemical Probes ◽  
Acetyl Coenzyme A ◽  
Acetyl Coenzyme ◽  
Histone Lysine ◽  
Lysine Acetyltransferase

Biomedically important histone lysine acetyltransferase KAT8 catalyses the acetyl coenzyme A-dependent acetylation of lysine on histone and other proteins. Here, we explore the ability of human KAT8 to catalyse the acetylation of histone H4 peptides possessing lysine and its analogues at position 16 (H4K16). Our synthetic and enzymatic studies on chemically and structurally diverse lysine mimics demonstrate that KAT8 also has a capacity to acetylate selected lysine analogues that possess subtle changes on the side chain and main chain. Overall, this work highlights that KAT8 has a broader substrate scope beyond natural lysine, and contributes to the design of new chemical probes targeting KAT8 and other members of the histone lysine acetyltransferase (KAT) family.

scholarly journals Side-Chain to Main-Chain Hydrogen Bonding Controls the Intrinsic Backbone Dynamics of the Amyloid Precursor Protein Transmembrane Helix

2014 ◽  
Vol 106 (6) ◽  
pp. 1318-1326 ◽  
Author(s):  
Christina Scharnagl ◽  
Oxana Pester ◽  
Philipp Hornburg ◽  
Daniel Hornburg ◽  
Alexander Götz ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Amyloid Precursor Protein ◽  
Main Chain ◽  
Transmembrane Helix ◽  
Precursor Protein ◽  
Backbone Dynamics ◽  
Side Chain

scholarly journals Methylofuran is a prosthetic group of the formyltransferase/hydrolase complex and shuttles one-carbon units between two active sites

2019 ◽  
Vol 116 (51) ◽  
pp. 25583-25590 ◽  
Author(s):  
Jethro L. Hemmann ◽  
Tristan Wagner ◽  
Seigo Shima ◽  
Julia A. Vorholt
Keyword(s):  
Active Sites ◽  
Bacterial Species ◽  
Methanogenic Archaea ◽  
Side Chain ◽  
Strong Interactions ◽  
Prosthetic Group ◽  
Additional Function ◽  
Amide Bonds ◽  
Consecutive Reactions ◽  
The One

Methylotrophy, the ability of microorganisms to grow on reduced one-carbon substrates such as methane or methanol, is a feature of various bacterial species. The prevailing oxidation pathway depends on tetrahydromethanopterin (H4MPT) and methylofuran (MYFR), an analog of methanofuran from methanogenic archaea. Formyltransferase/hydrolase complex (Fhc) generates formate from formyl-H4MPT in two consecutive reactions where MYFR acts as a carrier of one-carbon units. Recently, we chemically characterized MYFR from the model methylotrophMethylorubrum extorquensand identified an unusually long polyglutamate side chain of up to 24 glutamates. Here, we report on the crystal structure of Fhc to investigate the function of the polyglutamate side chain in MYFR and the relatedness of the enzyme complex with the orthologous enzymes in archaea. We identified MYFR as a prosthetic group that is tightly, but noncovalently, bound to Fhc. Surprisingly, the structure of Fhc together with MYFR revealed that the polyglutamate side chain of MYFR is branched and contains glutamates with amide bonds at both their α- and γ-carboxyl groups. This negatively charged and branched polyglutamate side chain interacts with a cluster of conserved positively charged residues of Fhc, allowing for strong interactions. The MYFR binding site is located equidistantly from the active site of the formyltransferase (FhcD) and metallo-hydrolase (FhcA). The polyglutamate serves therefore an additional function as a swinging linker to shuttle the one-carbon carrying amine between the two active sites, thereby likely increasing overall catalysis while decreasing the need for high intracellular MYFR concentrations.

scholarly journals Synthesis and Photochemical Reaction of Polymers Containing Norbornadiene Residues Both in the Main Chain and Side Chain.

2000 ◽  
Vol 57 (9) ◽  
pp. 569-576 ◽  
Author(s):  
Makoto SAMPEI ◽  
Ken HIRAMATU ◽  
Atsushi KAMEYAMA ◽  
Tadatomi NISHIKUBO
Keyword(s):  
Photochemical Reaction ◽  
Main Chain ◽  
Side Chain

Salt bridges in model peptides

1988 ◽  
Vol 53 (11) ◽  
pp. 2810-2824 ◽  
Author(s):  
Ilmars Sekacis ◽  
Mark Shenderovich ◽  
Gregory Nikiforovich ◽  
Edvards Liepinš ◽  
Ludmila Polevaya ◽  
...  
Keyword(s):  
Synthetic Peptides ◽  
Salt Bridge ◽  
Peptide Bond ◽  
Space Structure ◽  
Side Chain ◽  
Amino Group ◽  
Salt Bridges ◽  
Ionic Bond ◽  
Theoretical Conformational Analysis ◽  
H Nmr

A group of synthetic peptides including Boc-Lys-Phe-X-Y, X = Ala (I, III) or Thr (II), Y = Pro (I, II) or Ala (III) was studied by means of 1H NMR spectroscopy and theoretical conformational analysis. Compound I in DMSO shows two conformers with the trans- and cis-configuration of the peptide bond Ala-Pro. The salt bridge between the Lys ε-amino group and the C-terminal carboxyl is featured by magnetic nonequivalence of the Lys CεH2 protons. The space structure of I and II was found to possess a salt bridge fixed by an unusual turn in the chain formed by the Lys side chain and the C-terminal dipeptide with the trans-peptide bond X-Pro. Since a stable ionic bond in III and in the cis-conformer of I has not been observed, its contribution to stabilization of the space structure of the peptides in DMSO appears rather small.

Thermosetting Mechanism Study of Organosilicon Polymer Containing Carborane by Solid-State NMR Spectroscopy

1999 ◽  
Vol 576 ◽  
Author(s):  
H. Kimura ◽  
K. Okita ◽  
M. Ichitani ◽  
M. Yonezawa ◽  
T. Sugimoto
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Nmr Spectra ◽  
Main Chain ◽  
Addition Reaction ◽  
Side Chain ◽  
Mechanism Study ◽  
Nmr Method ◽  
Organosilicon Polymer ◽  
Thermal Stable

ABSTRACTThe thermosetting mechanism of an organosilicon polymer containing carborane has been studied utilizing the 13and 29Si solid-state NMR method. The polymer having C≡C bonds in the main chain and CH═CH2, Si-H bonds, and carborane in the bulky side chain, shows a very highly thermal stability in air by curing. From 13C and 29Si NMR spectra of the polymer, it was found that the intermolecular cross-linking reactions of the polymer was due to (1) the diene reaction between Ph-C≡C and C≡C and (2) the addition reaction between side chain terminal and Ph-C≡C and between CH═CH2 and Si–H, and a very highly thermal stable structure is formed.

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