scholarly journals A New Thermophilic Ene-Reductase from the Filamentous Anoxygenic Phototrophic Bacterium Chloroflexus aggregans

2021 ◽  
Vol 9 (5) ◽  
pp. 953
Author(s):  
Marina Simona Robescu ◽  
Mattia Niero ◽  
Giovanni Loprete ◽  
Laura Cendron ◽  
Elisabetta Bergantino
Keyword(s):  
Crystal Structure ◽  
Crystal Packing ◽  
Solvent Tolerance ◽  
Class Iii ◽  
Ph Optimum ◽  
Anoxygenic Phototrophic Bacterium ◽  
Wide Range ◽  
The Family ◽  
High Yields

Aiming at expanding the biocatalytic toolbox of ene-reductase enzymes, we decided to explore photosynthetic extremophile microorganisms as unique reservoir of (new) biocatalytic activities. We selected a new thermophilic ene-reductase homologue in Chloroflexus aggregans, a peculiar filamentous bacterium. We report here on the functional and structural characterization of this new enzyme, which we called CaOYE. Produced in high yields in recombinant form, it proved to be a robust biocatalyst showing high thermostability, good solvent tolerance and a wide range of pH optimum. In a preliminary screening, CaOYE displayed a restricted substrate spectrum (with generally lower activities compared to other ene-reductases); however, given the amazing metabolic ductility and versatility of Chloroflexus aggregans, further investigations could pinpoint peculiar chemical activities. X-ray crystal structure has been determined, revealing conserved features of Class III (or thermophilic-like group) of the family of Old Yellow Enzymes: in the crystal packing, the enzyme was found to assemble as dimer even if it behaves as a monomer in solution. The description of CaOYE catalytic properties and crystal structure provides new details useful for enlarging knowledge, development and application of this class of enzymes.

scholarly journals Crystal structure of a mononuclear RuIIcomplex with a back-to-back terpyridine ligand: [RuCl(bpy)(tpy–tpy)]+

2015 ◽  
Vol 71 (9) ◽  
pp. 1017-1021 ◽  
Author(s):  
Francisca N. Rein ◽  
Weizhong Chen ◽  
Brian L. Scott ◽  
Reginaldo C. Rocha
Keyword(s):  
Crystal Structure ◽  
Crystal Packing ◽  
Bidentate Ligand ◽  
Octahedral Geometry ◽  
Distorted Octahedral Geometry ◽  
Stacking Interactions ◽  
Bite Angle ◽  
Distorted Octahedral ◽  
The Mean

We report the structural characterization of [6′,6′′-bis(pyridin-2-yl)-2,2′:4′,4′′:2′′,2′′′-quaterpyridine](2,2′-bipyridine)chloridoruthenium(II) hexafluoridophosphate, [RuCl(C10H8N2)(C30H20N6)]PF6, which contains the bidentate ligand 2,2′-bipyridine (bpy) and the tridendate ligand 6′,6′′-bis(pyridin-2-yl)-2,2′:4′,4′′:2′′,2′′′-quaterpyridine (tpy–tpy). The [RuCl(bpy)(tpy–tpy)]+monocation has a distorted octahedral geometry at the central RuIIion due to the restricted bite angle [159.32 (16)°] of the tridendate ligand. The Ru-bound tpy and bpy moieties are nearly planar and essentially perpendicular to each other with a dihedral angle of 89.78 (11)° between the least-squares planes. The lengths of the two Ru—N bonds for bpy are 2.028 (4) and 2.075 (4) Å, with the shorter bond being opposite to Ru—Cl. For tpy–tpy, the mean Ru—N distance involving the outer N atomstransto each other is 2.053 (8) Å, whereas the length of the much shorter bond involving the central N atom is 1.936 (4) Å. The Ru—Cl distance is 2.3982 (16) Å. The free uncoordinated moiety of tpy–tpy adopts atrans,transconformation about the interannular C—C bonds, with adjacent pyridyl rings being only approximately coplanar. The crystal packing shows significant π–π stacking interactions based on tpy–tpy. The crystal structure reported here is the first for a tpy–tpy complex of ruthenium.

scholarly journals Transcriptome-wide Identification and Characterization of microRNAs and Their Targets in a Highly Adaptable Conifer Platycladus orientalis

2022 ◽  
Vol 147 (1) ◽  
pp. 7-17
Author(s):  
Ying Yang ◽  
Xian-Ge Hu ◽  
Bingsong Zheng ◽  
Yue Li ◽  
Tongli Wang ◽  
...  
Keyword(s):  
Stress Tolerance ◽  
Leucine Zipper ◽  
Class Iii ◽  
Conifer Species ◽  
Essential Information ◽  
Sequencing Platform ◽  
Platycladus Orientalis ◽  
Wide Range ◽  
Identification And Characterization

MicroRNAs (miRNAs) are short noncoding RNAs (20–25 nucleotides) that regulate gene expression posttranscriptionally. However, identification and characterization of miRNAs remain limited for conifer species. In this study, we applied transcriptome-wide miRNAs sequencing to a conifer species Platycladus orientalis, which is highly adaptable to a wide range of environmental adversities, including drought, barren soil, and mild salinity. A total of 17,181,542 raw reads were obtained from the Illumina sequencing platform; 31 conserved and 91 novel miRNAs were identified, and their unique characteristics were further analyzed. Ten randomly selected miRNAs were validated by quantificational real-time polymerase chain reaction. Through miRNA target predictions based on psRNATarget, 2331 unique mRNAs were predicted to be targets of P. orientalis miRNAs that involved in 187 metabolic pathways in KEGG database. These targets included not only important transcription factors (e.g., class III homeodomain leucine zipper targeted by por-miR166d) but also indispensable nontranscriptional factor proteins (i.e., por-miR482a-3p regulated nucleotide-binding site leucine-rich repeat protein). Interestingly, six miRNAs (por-miR16, -miR44, -miR60-5p, -miR69–3p, -miR166b-5p, and -miR395c) were found in adaptation-related pathways (e.g., drought), indicating their possible involved in this species’ stress-tolerance characteristics. The present study provided essential information for understanding the regulatory role of miRNAs in P. orientalis and sheds light on their possible use in tree improvement for stress tolerance.

scholarly journals A biphasic oxidation of alcohols to aldehydes and ketones using a simplified packed-bed microreactor

2009 ◽  
Vol 5 ◽  
Author(s):  
Andrew Bogdan ◽  
D Tyler McQuade
Keyword(s):  
Packed Bed ◽  
Secondary Alcohols ◽  
Great Stability ◽  
Wide Range ◽  
Oxidation Of Alcohols ◽  
Aldehydes And Ketones ◽  
High Yields ◽  
By Products ◽  
Over Time

We demonstrate the preparation and characterization of a simplified packed-bed microreactor using an immobilized TEMPO catalyst shown to oxidize primary and secondary alcohols via the biphasic Anelli-Montanari protocol. Oxidations occurred in high yields with great stability over time. We observed that plugs of aqueous oxidant and organic alcohol entered the reactor as plugs but merged into an emulsion on the packed-bed. The emulsion coalesced into larger plugs upon exiting the reactor, leaving the organic product separate from the aqueous by-products. Furthermore, the microreactor oxidized a wide range of alcohols and remained active in excess of 100 trials without showing any loss of catalytic activity.

A Green Approach for the Synthesis of Novel 7,11-Dihydro-6H-chromeno[3,4-e]isoxazolo[5,4-b]pyridin-6-one Derivatives Using Acidic Ionic Liquid [C4mim][HSO4]

2016 ◽  
Vol 69 (9) ◽  
pp. 1049 ◽  
Author(s):  
Sudesh Kumari ◽  
M. Rajeswari ◽  
Jitender M. Khurana
Keyword(s):  
Ionic Liquid ◽  
Crystal Packing ◽  
Aromatic Aldehydes ◽  
Green Solvent ◽  
One Pot ◽  
X Ray ◽  
Acidic Ionic Liquid ◽  
Green Approach ◽  
Wide Range ◽  
High Yields

A multicomponent reaction capable of affording a wide range of novel 7,11-dihydro-6H-chromeno[3,4-e]isoxazolo[5,4-b]pyridin-6-one derivatives via one-pot three-component condensation of 4-hydroxycoumarin, aromatic aldehydes, and 5-amino-3-methylisoxazole in ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate ([C4mim][HSO4]) is reported. Structures have been confirmed by spectral and X-ray studies. Crystal packing of 4b has also been reported. Green solvent, short reaction time, easy workup, and high yields are the salient features of the present protocol.

scholarly journals PARTIAL CHARACTERIZATION of lipase from COCOA BEANS (Theobroma cacao. L.) of clone PBC 159

2010 ◽  
Vol 8 (3) ◽  
pp. 448-453
Author(s):  
Ratna Agung Samsumaharto
Keyword(s):  
Theobroma Cacao ◽  
Cocoa Bean ◽  
Cocoa Beans ◽  
Ph Optimum ◽  
Nitrobenzoic Acid ◽  
Lipase Enzyme ◽  
Wide Range ◽  
Km Value ◽  
Theobroma Cacao L

A study was carried out to characterize the cocoa lipase from cocoa beans (Theobroma cacao, L.) of clone PBC 159. The optimum temperature of cocoa lipase was 30-40 °C and the pH optimum was 7.0-8.0. The moleculer weight of the lipase enzyme was in between 45-66 kDa. The results indicate that Km value for cocoa bean lipase was 2.63 mM, when trimyristin was used as a substrate. The incubation of cocoa bean lipase with triolein and tributyrin (as substrate) yielded Km of 11.24 and 35.71 mM, respectively. The Vmax value obtained from the incubation of the lipase with a wide range of substrates, including tributyrin, trimyristin and triolein, are expressed as µmole acid/min/mg protein for cocoa lipase. Vmax values decreased with the increase in the triacylglycerol chain-length, with Vmax values of 27.78, 13.16 and 11.63 µmole acid/min/mg protein when incubated with tributyrin, trimyristin and triolein, respectively. Inhibition of lipase occurred in the presence of diisopropyl flourophosphate, N-bromosuccinimide and 5,5-dithiobis-(-2-nitrobenzoic acid).   Keywords: characterization, lipase, cocoa beans

Channel-Type Crystal Packing in the Very Rare Space Group P4212 with Z' = 3/4: Crystal Structure of the Complex γ-Cyclodextrin–Methanol–n-Hydrate

1998 ◽  
Vol 54 (4) ◽  
pp. 450-455 ◽  
Author(s):  
T. Steiner ◽  
W. Saenger
Keyword(s):  
Crystal Structure ◽  
Crystal Packing ◽  
Cell Content ◽  
Guest Molecules ◽  
Space Group ◽  
Cyclodextrin Inclusion Complexes ◽  
Packing Arrangement ◽  
Type Crystal ◽  
Channel Type

The crystal structure of the title compound is discussed with focus on its unusual crystal packing mode. The γ-cyclodextrin molecules stack in columns which have internal channels and additional large channels are formed between the columns. Both types of channels are so wide that more or less free diffusion of water and small guest molecules is possible, preventing characterization of the solvent and guest arrangements. Although the space group P4212 (no. 90) and the unit-cell content Z′ = 3\over 4 are extremely rare in general, this is the favorite crystal packing arrangement of γ-cyclodextrin inclusion complexes. This space group has not been observed as yet for other purely organic compounds.

Purine catabolism in man: characterization of placental microsomal 5′-nucleotidase

1976 ◽  
Vol 54 (5) ◽  
pp. 462-469 ◽  
Author(s):  
Irving H. Fox ◽  
Pamela J. Marchant
Keyword(s):  
Specific Activity ◽  
Ph Optimum ◽  
Electrophoretic Variants ◽  
Molecular Weights ◽  
Wide Range ◽  
Stokes Radius ◽  
Michaelis Constants ◽  
Light Form ◽  
Molecular Weight Form

Human placental microsomal 5′-nucleotidase (EC 3.1.3.5) was prepared free of alkaline phosphatase by isoelectric focusing. A total of seven electrophoretic variants were isolated during the preparation of six placentas. Only three to six variants were found in a single placenta. The isoelectric pH's were 6.70, 6.44, 6.23, 6.02, 5.76, 5.63 and 5.44. These were found to be composed of variable quantities of a large, medium and low molecular weight form. The apparent molecular weights of the medium and light form of the enzyme were 86 500 and 43 500, respectively, as estimated from Stokes radius and sedimentation velocity determinations. The electrophoretic variants were not distinguishable with respect to specific activity and Michaelis constants for AMP, GMP or CMP or inhibition by ATP, CTP or adenosine. These electrophoretic variants appeared to be pseudoisozymes based upon different states of aggregation of a common primary sequence.There was a wide range of substrate specificity among nucleoside 5′-monophosphates which included 2-deoxyribose compounds. With AMP as 100, substrate activity was: CMP, 122; NMN, 74; GMP, 68; IMP, 63; XMP, 28 and UDP–glucose, 68. The Michaelis constants for AMP, GMP and CMP ranged from 12–18 μM, from 33–67 μM and from 170–250 μM, respectively. Although 5′-nucleotidase was active in the absence of divalent cation, 5 mM MgCl2 stimulated the enzyme activity to 234% of control and shifted the pH optimum of 9.8 to a plateau from pH 7.4–9.8.

Applications of the Cambridge Structural Database in organic chemistry and crystal chemistry

2002 ◽  
Vol 58 (3) ◽  
pp. 407-422 ◽  
Author(s):  
Frank H. Allen ◽  
W. D. Samuel Motherwell
Keyword(s):  
Organic Chemistry ◽  
Crystal Structure ◽  
Crystal Chemistry ◽  
Crystal Engineering ◽  
Structure Prediction ◽  
Crystal Packing ◽  
Cambridge Structural Database ◽  
Software Systems ◽  
Wide Range ◽  
Structural Database

The Cambridge Structural Database (CSD) and its associated software systems have formed the basis for more than 800 research applications in structural chemistry, crystallography and the life sciences. Relevant references, dating from the mid-1970s, and brief synopses of these papers are collected in a database, DBUse, which is freely available via the CCDC website. This database has been used to review research applications of the CSD in organic chemistry, including supramolecular applications, and in organic crystal chemistry. The review concentrates on applications that have been published since 1990 and covers a wide range of topics, including structure correlation, conformational analysis, hydrogen bonding and other intermolecular interactions, studies of crystal packing, extended structural motifs, crystal engineering and polymorphism, and crystal structure prediction. Applications of CSD information in studies of crystal structure precision, the determination of crystal structures from powder diffraction data, together with applications in chemical informatics, are also discussed.

A Scalable Multi-Functional Thermal Test Chip Family: Design and Evaluation

2001 ◽  
Vol 123 (4) ◽  
pp. 323-330 ◽  
Author(s):  
Zs. Benedek ◽  
B. Courtois ◽  
G. Farkas ◽  
E. Kolla´r ◽  
S. Mir ◽  
...  
Keyword(s):  
Temperature Sensor ◽  
Thermal Characterization ◽  
Thermal Engineering ◽  
Test Chip ◽  
Basic Cell ◽  
Thermal Test ◽  
Wide Range ◽  
The Family ◽  
Test Chips

Nowadays, thermal characterization of IC packages and packaging technologies is becoming a key task in thermal engineering. To support this by measurements, we developed a family of thermal test chips that allow a wide range of possible applications. Our chips are based on the same basic cell that is mainly covered by dissipating resistors and also contains a temperature sensor. These basic cells are organized into arrays of different size. The arrays are designed such that further “super arrays” can also be built for tiling up larger package cavities. The first members of the family, TMC9 and TMC81, have been manufactured. Our measurements show that the goals aimed at the design have been achieved.

scholarly journals Crystal structures of two isostructural thiosemicarbazones and DFT calculations

2014 ◽  
Vol 70 (a1) ◽  
pp. C1711-C1711
Author(s):  
Rafael Meroño ◽  
Santiago Granda ◽  
Klaus Merz ◽  
R.R Saravanan ◽  
S. Seshadri ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Crystal Packing ◽  
Vibrational Frequencies ◽  
Basis Set ◽  
Drug Candidate ◽  
Compound I ◽  
Acetophenone Derivatives ◽  
Molecular Stability ◽  
Wide Range

The families of thiosemicarbazone compounds have been extensively studied due to their wide range potential in medical applications [1]. Some studies with acetophenone derivatives and their coordination complexes [2] reveal that these compounds could be used as a new class of anti-trypanosomal drug candidate. In view of the importance of these compounds, two new thiosemicarbazones (I) and (II) have been synthesized (compound I substituted with Chloro atom and compound II substituted with Bromine atom), and their crystal structure features are presented here. The crystal structures are isostructural and the molecules crystallize in a P21/c space group. In the crystal packing the molecules are connected through N-H···S hydrogen bonds to form a centrosymmetric synthon. The optimized geometry of the compound (I) was calculated from the DFT–B3LYP gradient calculations employing 6-31G (d,p) basis set and calculated vibrational frequencies are evaluated via comparison with experimental values. Molecular stability has been analyzed using Natural Bond Orbital (NBO) and Natural Localized Molecular Orbital (NLMO) analysis and the limits of the molecular electrostatic potential calculated. The HOMO and LUMO energies shows the charge transfer occurs within the molecule. The results showed no significant geometrical differences (distances and angles), when the solid state crystal structure is compared with the optimized structure in the gas phase. Very good agreements have been found between principal vibrational frequencies calculated from the optimized structure and the experimental spectroscopic data [3]. We thank financial support from Spanish Ministerio de Economía y Competitividad (MAT2010-15094, Factoría de Cristalización– Consolider Ingenio 2010, ERDF funds and German Academic Exchange Service (DAAD).

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