scholarly journals A New L-Proline Amide Hydrolase with Potential Application within the Amidase Process

Crystals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 18
Author(s):  
Sergio Martinez-Rodríguez ◽  
Rafael Contreras-Montoya ◽  
Jesús M. Torres ◽  
Luis Álvarez de Cienfuegos ◽  
Jose Antonio Gavira
Keyword(s):  
Amino Acid ◽  
Pseudomonas Syringae ◽  
Hydrolytic Activity ◽  
Optimal Conditions ◽  
X Ray ◽  
Canonical Amino Acid ◽  
Amide Hydrolase ◽  
Key Residues ◽  
Thermal Melting

L-proline amide hydrolase (PAH, EC 3.5.1.101) is a barely described enzyme belonging to the peptidase S33 family, and is highly similar to prolyl aminopeptidases (PAP, EC. 3.4.11.5). Besides being an S-stereoselective character towards piperidine-based carboxamides, this enzyme also hydrolyses different L-amino acid amides, turning it into a potential biocatalyst within the Amidase Process. In this work, we report the characterization of L-proline amide hydrolase from Pseudomonas syringae (PsyPAH) together with the first X-ray structure for this class of L-amino acid amidases. Recombinant PsyPAH showed optimal conditions at pH 7.0 and 35 °C, with an apparent thermal melting temperature of 46 °C. The enzyme behaved as a monomer at the optimal pH. The L-enantioselective hydrolytic activity towards different canonical and non-canonical amino-acid amides was confirmed. Structural analysis suggests key residues in the enzymatic activity.

Characterization of amino acid adlayers on InAs surfaces using X-ray photoelectron spectroscopy

2009 ◽  
Vol 172 (1-3) ◽  
pp. 47-53 ◽  
Author(s):  
John W.J. Slavin ◽  
Upasana Jarori ◽  
Dmitry Zemlyanov ◽  
Albena Ivanisevic
Keyword(s):  
Amino Acid ◽  
Photoelectron Spectroscopy ◽  
X Ray

scholarly journals Synthesis and Characterization of Various Amino Acid Derived Thiohydantoins

Proceedings ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 37
Author(s):  
Petar Stanić ◽  
Marija Živković ◽  
Biljana Šmit
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Allyl Isothiocyanate ◽  
Structural Diversity ◽  
Biologically Active ◽  
Reaction Conditions ◽  
X Ray ◽  
X Ray Crystallography ◽  
Sulfur Containing

Hydantoins and their sulfur containing analogues, thiohydantoins, are cyclic ureides that have attracted huge attention ever since their discovery. Most of them are biologically active compounds and several points of structural diversity have made them very synthetically attractive. Although substituents can be introduced to the hydantoin nucleus, most substituted hydantoins are synthesized from substrates already containing these groups, while forming the hydantoin nucleus. This is a common route to the synthesis of hydantoins and one of them is employed in this study. A series of 3-allyl-2-thiohydantoins is synthesized from various α-amino acids in a reaction with allyl isothiocyanate. The substitution of the acquired thiohydantoin depends on the structure of the starting α-amino acid. The residual group of the α-amino acid becomes the substituent at the C5-position, while N-monosubstituted amino acids give rise to a substituent in the N1-position. The reaction is carried out in a two-step process and the reaction conditions generally depend on the nature of the amino acid itself. All thiohydantoins are obtained in a good yield and fully characterized by NMR and IR spectroscopy, as well as X-ray crystallography.

Preparation and Characterization of Lignin Powder Micronized by a Supercritical Antisolvent (SAS) Process

2011 ◽  
Vol 233-235 ◽  
pp. 1642-1645 ◽  
Author(s):  
Qi Lu ◽  
Yuan Gang Zu ◽  
Lei Yang ◽  
Xiu Hua Zhao ◽  
Wen Jun Liu ◽  
...  
Keyword(s):  
Particle Size ◽  
Optimal Conditions ◽  
Orthogonal Array Design ◽  
X Ray Diffraction ◽  
Array Design ◽  
X Ray ◽  
Mean Particle Size ◽  
Supercritical Antisolvent ◽  
The Mean

Nanoscale lignin was successfully prepared with a supercritical antisolvent (SAS) apparatus using acetone as a solvent and superciritical carbon dioxide as an antisolvent. Four factors were studied and optimized by a four-level orthogonal array design (OAD). According to analysis of variance, precipitation pressure had a significant effect on mean particle size. The optimal conditions are as follows: precipitation temperature 35 °C, precipitation pressure 30 MPa, temperature difference +10 °C and concentration of lignin solution 0.5 mg/mL. The micronized lignin under the optimal conditions was characterized by Scanning Electron Microscopy (SEM), Fourier-transform Infrared Spectroscopy (FTIR), Dynamic Light Scattering (DLS) and X-Ray Diffraction (XRD) analyses. The results showed the mean particle size of micronized lignin was 0.144 ± 0.03 μm and had no degradation. The solubility of micronized lignin was improved significantly in distilled water.

Growth and Characterization of High Quality MgO Thin Films by Ultrasonic Spray Pyrolysis

2007 ◽  
Vol 280-283 ◽  
pp. 1171-1174 ◽  
Author(s):  
Ji Ming Bian ◽  
Xiao Min Li ◽  
Xiang Dong Gao ◽  
Wei Dong Yu
Keyword(s):  
Thin Films ◽  
Spray Pyrolysis ◽  
Ultrasonic Spray Pyrolysis ◽  
Optimal Conditions ◽  
Quartz Glass Substrate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ultrasonic Spray ◽  
Resistivity Meter

Ultrasonic spray pyrolysis has been applied to deposit MgO thin films on Si(100) and quartz glass substrate. The microstructures and properties of the as-grown MgO thin films were examined by X-ray diffraction, scanning electron microscopy, spectrophotometer and semiconductor resistivity meter. The results indicates that the MgO thin films deposited under optimal conditions shows smooth and dense surface without visible pores or defects over the substrate, and as well as good thickness uniformity. Almost completely (100)-oriented MgO films with the transmission higher than 90% in UV/VIS region and the resistivity at least in the order of 107Ω-cm were obtained. MgO thin film with such a crystal quality seems to be very suitable for acting as a buffer layer for the subsequent epitaxial growth of films.

scholarly journals Functional and Structural Characterization of Thermostable d-Amino Acid Aminotransferases from Geobacillus spp.

2006 ◽  
Vol 72 (2) ◽  
pp. 1588-1594 ◽  
Author(s):  
Seung-Goo Lee ◽  
Seung-Pyo Hong ◽  
Jae Jun Song ◽  
Su-Jin Kim ◽  
Mi-Sun Kwak ◽  
...  
Keyword(s):  
Amino Acid ◽  
Salt Bridge ◽  
Hypothetical Protein ◽  
Structural Aspect ◽  
Turnover Rates ◽  
Highly Active ◽  
Key Residues ◽  
Structural Alignments ◽  
Limited Sequence

ABSTRACT d-Amino acid aminotransferases (d-AATs) from Geobacillus toebii SK1 and Geobacillus sp. strain KLS1 were cloned and characterized from a genetic, catalytic, and structural aspect. Although the enzymes were highly thermostable, their catalytic capability was approximately one-third of that of highly active Bacilli enzymes, with respective turnover rates of 47 and 55 s−1 at 50°C. The Geobacillus enzymes were unique and shared limited sequence identities of below 45% with d-AATs from mesophilic and thermophilic Bacillus spp., except for a hypothetical protein with a 72% identity from the G. kaustophilus genome. Structural alignments showed that most key residues were conserved in the Geobacillus enzymes, although the conservative residues just before the catalytic lysine were distinctively changed: the 140-LRcD-143 sequence in Bacillus d-AATs was 144-EYcY-147 in the Geobacillus d-AATs. When the EYcY sequence from the SK1 enzyme was mutated into LRcD, a 68% increase in catalytic activity was observed, while the binding affinity toward α-ketoglutarate decreased by half. The mutant was very close to the wild-type in thermal stability, indicating that the mutations did not disturb the overall structure of the enzyme. Homology modeling also suggested that the two tyrosine residues in the EYcY sequence from the Geobacillus d-AATs had a π/π interaction that was replaceable with the salt bridge interaction between the arginine and aspartate residues in the LRcD sequence.

scholarly journals Rapid Structural Analysis of a Synthetic Non-canonical Amino Acid by Microcrystal Electron Diffraction

2021 ◽  
Vol 7 ◽  
Author(s):  
Patrick R. Gleason ◽  
Brent L. Nannenga ◽  
Jeremy H. Mills
Keyword(s):  
Amino Acid ◽  
Electron Diffraction ◽  
Structure Determination ◽  
Structural Model ◽  
Structural Information ◽  
Enzymatic Reaction ◽  
Unnatural Amino Acid ◽  
Resonance Spectroscopy ◽  
Canonical Amino Acid

Structural characterization of small molecules is a crucial component of organic synthesis. In this work, we applied microcrystal electron diffraction (MicroED) to analyze the structure of the product of an enzymatic reaction that was intended to produce the unnatural amino acid 2,4-dihydroxyphenylalanine (24DHF). Characterization of our isolated product with nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS) suggested that an isomer of 24DHF had been formed. Microcrystals present in the isolated product were then used to determine its structure to 0.62 Å resolution, which confirmed its identity as 2-amino-2-(2,4-dihydroxyphenyl)propanoic acid (24DHPA). Moreover, the MicroED structural model indicated that both enantiomeric forms of 24DHPA were present in the asymmetric unit. Notably, the entire structure determination process including setup, data collection, and refinement was completed in ~1 h. The MicroED data not only bolstered previous results obtained using NMR and MS but also immediately provided information about the stereoisomers present in the product, which is difficult to achieve using NMR and MS alone. Our results therefore demonstrate that MicroED methods can provide useful structural information on timescales that are similar to many commonly used analytical methods and can be added to the existing suite of small molecule structure determination tools in future studies.

scholarly journals X-ray fluorescence technique for studying mineral nutrients of Quinoa seed cultivated in Iraq

Bionatura ◽  
2019 ◽  
Vol 4 (4) ◽  
pp. 966-971
Author(s):  
Mohsin Raghdan H. ◽  
Risala H. Allami ◽  
Raghad S. Mouhamad
Keyword(s):  
Amino Acid ◽  
Chenopodium Quinoa ◽  
Acid Value ◽  
Essential Amino Acids ◽  
Fluorescence Technique ◽  
X Ray ◽  
Metal Composition ◽  
Amino Acid Profiles ◽  
Carbohydrate Contents

Quinoa (Chenopodium quinoa Wild) is a plant that recently has been successfully grown in Iraq, providing seeds rich in nutrients and bioactive compounds. The distribution of metal composition and amino acid value in the quinoa seed was determined using the X-Ray Fluorescence technique. The present study aimed at the characterization of chemical composition, nutritional value, and amino acid profiles of quinoa seed cultivated in Iraq. Moisture, ash, gross fat, gross protein, gross fiber and carbohydrate contents concerning quinoa seeds were ranged from 9.45 ± 0.22 %, 2.13 ± 0.045 %, 6.4 ± 0.043%, 6.4 ± 0.873 %،3.8 ± 0.044 % to1.67+68.1 % respectively. The current study was undertaken to Detection of active compounds in quinoa seed extract including, alkaline, flavonoids, phenols, glycosides, resins, and tannins, where all the findings were positive. It could be concluded that quinoa seed, cultivated in Iraq are a good source of essential nutrients such as minerals, essential amino acids.

scholarly journals TEM-109 (CMT-5), a Natural Complex Mutant of TEM-1 β-Lactamase Combining the Amino Acid Substitutions of TEM-6 and TEM-33 (IRT-5)

2005 ◽  
Vol 49 (11) ◽  
pp. 4443-4447 ◽  
Author(s):  
F. Robin ◽  
J. Delmas ◽  
C. Chanal ◽  
D. Sirot ◽  
J. Sirot ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Protein Sequence ◽  
Hydrolytic Activity ◽  
Conjugative Plasmid ◽  
Amino Acid Substitutions ◽  
Resistance Phenotype ◽  
Natural Complex ◽  
Synergy Test

ABSTRACT Escherichia coli CF349 exhibited a complex β-lactam resistance phenotype, including resistance to amoxicillin and ticarcillin alone and in combination with clavulanate and to some extended-spectrum cephalosporins. The double-disk synergy test was positive. CF349 harbored an 85-kb conjugative plasmid which encoded a β-lactamase of pI 5.9. The corresponding bla gene was identified by PCR and sequencing as a bla TEM gene. The deduced protein sequence revealed a new complex mutant of TEM-1 β-lactamase designated TEM-109 (CMT-5). TEM-109 contained both the substitutions Glu104Lys and Arg164His of the expanded-spectrum β-lactamase (ESBL) TEM-6 and Met69Leu of the inhibitor-resistant TEM-33 (IRT-5). TEM-109 exhibited hydrolytic activity against ceftazidime similar to that of TEM-6 (k cat, 56 s−1 and 105 s−1, respectively; Km values, 226 and 247 μM, respectively). The 50% inhibitory concentrations of clavulanate and tazobactam (0.13 μM and 0.27 μM, respectively) were 5- to 10-fold higher for TEM-109 than for TEM-6 (0.01 and 0.06 μM, respectively) but were almost 10-fold lower than those for TEM-33. The characterization of this novel CMT, which exhibits a low level of resistance to inhibitors, highlights the emergence of this new ESBL type.

Crystallization and Preliminary X-Ray Characterization of Branched-Chain Amino Acid Aminotransferase from Escherichia coli

1989 ◽  
Vol 105 (5) ◽  
pp. 671-672 ◽  
Author(s):  
Shigehiro Kamitori ◽  
Yoshihiko Odagaki ◽  
Katsura Inoue ◽  
Seiki Kuramitsu ◽  
Hiroyuki Kagamiyama ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
X Ray ◽  
Branched Chain Amino Acid ◽  
Branched Chain

scholarly journals Powder X-ray characterization of djenkolic acid

2001 ◽  
Vol 16 (1) ◽  
pp. 46-47
Author(s):  
Petr Melnikov ◽  
Alexandre Cuin ◽  
Pedro P. Corbi ◽  
Maurício Cavicchioli ◽  
Antonio C. Massabni
Keyword(s):  
Amino Acid ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Natural Amino Acid ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Cell Parameters ◽  
Orthorhombic Cell ◽  
Djenkolic Acid

X-ray powder diffraction data for the orthorhombic natural amino acid djenkolic acid, C7H14N2O4S2, is described in this paper. The orthorhombic cell parameters are: a=8.12 Å, b=12.16 Å, and c=5.38 Å

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