scholarly journals The amino-acid methionine; constitution and synthesis

1928 ◽  
Vol 22 (6) ◽  
pp. 1417-1425 ◽  
Author(s):  
George Barger ◽  
Frederick Philip Coyne
Keyword(s):  
Amino Acid ◽  
Amino Acid Methionine

Biogenic amino acid methionine-based corrosion inhibitors of mild steel in acidic media

2019 ◽  
Vol 26 (4) ◽  
pp. 467-482 ◽  
Author(s):  
L. K. M. O. Goni ◽  
M. A. Jafar Mazumder ◽  
S. A. Ali ◽  
M. K. Nazal ◽  
H. A. Al-Muallem
Keyword(s):  
Amino Acid ◽  
Mild Steel ◽  
Corrosion Inhibitors ◽  
Acidic Media ◽  
Amino Acid Methionine

scholarly journals Methionine in a protein hydrophobic core drives tight interactions required for assembly of spider silk

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Julia C. Heiby ◽  
Benedikt Goretzki ◽  
Christopher M. Johnson ◽  
Ute A. Hellmich ◽  
Hannes Neuweiler
Keyword(s):  
Amino Acid ◽  
Spider Silk ◽  
Tight Binding ◽  
Pivotal Role ◽  
Speed Limit ◽  
Hydrophobic Core ◽  
Complex Mechanism ◽  
Silk Proteins ◽  
Dragline Silk ◽  
Amino Acid Methionine

Abstract Web spiders connect silk proteins, so-called spidroins, into fibers of extraordinary toughness. The spidroin N-terminal domain (NTD) plays a pivotal role in this process: it polymerizes spidroins through a complex mechanism of dimerization. Here we analyze sequences of spidroin NTDs and find an unusually high content of the amino acid methionine. We simultaneously mutate all methionines present in the hydrophobic core of a spidroin NTD from a nursery web spider’s dragline silk to leucine. The mutated NTD is strongly stabilized and folds at the theoretical speed limit. The structure of the mutant is preserved, yet its ability to dimerize is substantially impaired. We find that side chains of core methionines serve to mobilize the fold, which can thereby access various conformations and adapt the association interface for tight binding. Methionine in a hydrophobic core equips a protein with the capacity to dynamically change shape and thus to optimize its function.

Fragmentation of the α-Amino Acid Methionine in Field Desorption Mass Spectrometry

1978 ◽  
Vol 33 (7) ◽  
pp. 770-781 ◽  
Author(s):  
J. van der Greef ◽  
N. M. M. Nibbering ◽  
H.-R. Schulten ◽  
W. D. Lehmann
Keyword(s):  
Mass Spectrometry ◽  
Amino Acid ◽  
Desorption Kinetics ◽  
Fragmentation Pattern ◽  
Field Desorption ◽  
Stable Isotope Labelling ◽  
Desorption Mass Spectrometry ◽  
Combined Use ◽  
Field Desorption Mass Spectrometry ◽  
Amino Acid Methionine

AbstractField Desorption Mass Spectrometry, a-Amino Acid Methionine The fragmentation of methionine in field desorption mass spectrometry has been studied. Decomposition mechanisms are described which are based on stable isotope labelling, low and high resolution field desorption, and the application of field desorption kinetics. The combined use of these techniques for the study of some fundamental fragmentations in field desorption is demonstrated successfully. Further, a comparison with the fragmentation pattern of methionine under electron impact, chemical ionization and Curie point pyrolysis is given.

scholarly journals ESAT-6 of Mycobacterium tuberculosis downregulates cofilin1 and reduces the phagosome acidification in infected macrophages

2020 ◽  
Author(s):  
P P Mahesh ◽  
R J Retnakumar ◽  
K C Sivakumar ◽  
Sathish Mundayoor
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Amino Acid ◽  
Anticancer Drug ◽  
Ectopic Expression ◽  
Dependent Manner ◽  
Filamentous Actin ◽  
Over Expression ◽  
Inactive Form ◽  
Amino Acid Methionine ◽  
Constitutively Active

AbstractMycobacterium tuberculosis when phagocytosed by macrophages is not cleared completely and many of the bacteria remain in phagosomes indefinitely. In this study we considered abnormal retention of filamentous actin on early phagosomes contributing to defective phagosome acidification. Phosphocofilin1, the inactive form of actin depolymerizing protein cofilin1, which leads to retention of filamentous actin, and the total filamentous actin itself were found upregulated in macrophages infected with virulent M. tuberculosis. Over expression of constitutively active cofilin1 in macrophages was found to increase phagosome acidification when infected with virulent M. tuberculosis. The anticancer drug sorafenib which activates cofilin1 in PI3K dependent manner was also found to increase phagosome acidification. Cofilin1, known to be positively regulated by superoxide was found to be downregulated by ESAT-6 of M. tuberculosis where the latter is known to reduce ROS in macrophages. Ectopic expression of ESAT-6 in macrophages was found to increase filamentous actin and to transform the macrophages more spindle shaped. ESAT-6 was also found to decrease phagosome acidification in macrophages infected with an avirulent M. tuberculosis strain. Finally, this study proposes a role for the amino acid methionine in resisting ROS by creating M93 mutants of ESAT-6.

The determination of total sulphur and sulphate sulphur in feeding stuffs

1933 ◽  
Vol 23 (3) ◽  
pp. 459-462 ◽  
Author(s):  
H. E. Woodman
Keyword(s):  
Amino Acid ◽  
Recent Work ◽  
Present Note ◽  
Directed Attention ◽  
Plant Products ◽  
Total Sulphur ◽  
Sulphate Sulphur ◽  
Inorganic Sulphur ◽  
Amino Acid Methionine

Recent work on the growth of wool in relation to the cystine supply in the sheep's diet, together with the discovery in proteins of a new sulphur-containing amino acid, methionine, has directed attention to the importance of being able to determine, by methods easily and quickly carried out, the amounts of total and inorganic sulphur in plant products and feeding stuffs. Details are given in the present note of the methods employed by the writers for the estimation of total sulphur, sulphate sulphur and, by difference, organic sulphur.

A novel cyclopolymer containing residues of essential amino acid methionine: synthesis and application

2015 ◽  
Vol 24 (7) ◽  
pp. 541-547 ◽  
Author(s):  
Hasan A. Al-Muallem ◽  
Mohammad A. J. Mazumder ◽  
Mohamad K. Estaitie ◽  
Shaikh A. Ali
Keyword(s):  
Amino Acid ◽  
Essential Amino Acid ◽  
Amino Acid Methionine ◽  
Methionine Synthesis

scholarly journals Initiation of Protein Synthesis in Mammalian Cells with Codons Other Than AUG and Amino Acids Other Than Methionine

1998 ◽  
Vol 18 (9) ◽  
pp. 5140-5147 ◽  
Author(s):  
Harold J. Drabkin ◽  
Uttam L. RajBhandary
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Mammalian Cells ◽  
Initiator Trna ◽  
Cell Extracts ◽  
Potential Applications ◽  
Protein Synthesis Initiation ◽  
Amino Acid Methionine ◽  
The Many

ABSTRACT Protein synthesis is initiated universally with the amino acid methionine. In Escherichia coli, studies with anticodon sequence mutants of the initiator methionine tRNA have shown that protein synthesis can be initiated with several other amino acids. In eukaryotic systems, however, a yeast initiator tRNA aminoacylated with isoleucine was found to be inactive in initiation in mammalian cell extracts. This finding raised the question of whether methionine is the only amino acid capable of initiation of protein synthesis in eukaryotes. In this work, we studied the activities, in initiation, of four different anticodon sequence mutants of human initiator tRNA in mammalian COS1 cells, using reporter genes carrying mutations in the initiation codon that are complementary to the tRNA anticodons. The mutant tRNAs used are aminoacylated with glutamine, methionine, and valine. Our results show that in the presence of the corresponding mutant initiator tRNAs, AGG and GUC can initiate protein synthesis in COS1 cells with methionine and valine, respectively. CAG initiates protein synthesis with glutamine but extremely poorly, whereas UAG could not be used to initiate protein synthesis with glutamine. We discuss the potential applications of the mutant initiator tRNA-dependent initiation of protein synthesis with codons other than AUG for studying the many interesting aspects of protein synthesis initiation in mammalian cells.

scholarly journals Potential Implications of Interactions between Fe and S on Cereal Fe Biofortification

2020 ◽  
Vol 21 (8) ◽  
pp. 2827 ◽  
Author(s):  
Yuta Kawakami ◽  
Navreet K. Bhullar
Keyword(s):  
Amino Acid ◽  
Essential Elements ◽  
Metal Chelators ◽  
Physiological Processes ◽  
Cereal Species ◽  
Fe Uptake ◽  
Amino Acid Methionine ◽  
Fe Homeostasis

Iron (Fe) and sulfur (S) are two essential elements for plants, whose interrelation is indispensable for numerous physiological processes. In particular, Fe homeostasis in cereal species is profoundly connected to S nutrition because phytosiderophores, which are the metal chelators required for Fe uptake and translocation in cereals, are derived from a S-containing amino acid, methionine. To date, various biotechnological cereal Fe biofortification strategies involving modulation of genes underlying Fe homeostasis have been reported. Meanwhile, the resultant Fe-biofortified crops have been minimally characterized from the perspective of interaction between Fe and S, in spite of the significance of the crosstalk between the two elements in cereals. Here, we intend to highlight the relevance of Fe and S interrelation in cereal Fe homeostasis and illustrate the potential implications it has to offer for future cereal Fe biofortification studies.

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