scholarly journals Crystallization and X-ray diffraction analysis of SpaE, a basal pilus protein from the gut-adaptedLactobacillus rhamnosusGG

2017 ◽  
Vol 73 (6) ◽  
pp. 321-327 ◽  
Author(s):  
Arjun K. Mishra ◽  
Abhin Kumar Megta ◽  
Airi Palva ◽  
Ingemar von Ossowski ◽  
Vengadesan Krishnan
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Molecular Mechanisms ◽  
Recombinant Expression ◽  
Lactobacillus Rhamnosus ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pilin Subunit ◽  
Sad Phasing

SpaE is the predicted basal pilin subunit in the sortase-dependent SpaFED pilus from the gut-adapted and commensalLactobacillus rhamnosusGG. Thus far, structural characterization of the cell-wall-anchoring basal pilins has remained difficult and has been limited to only a few examples from pathogenic genera and species. To gain a further structural understanding of the molecular mechanisms that are involved in the anchoring and assembly of sortase-dependent pili in less harmful bacteria,L. rhamnosusGG SpaE for crystallization was produced by recombinant expression inEscherichia coli. Although several attempts to crystallize the SpaE protein were unsuccessful, trigonal crystals that diffracted to a resolution of 3.1 Å were eventually produced using PEG 3350 as a precipitant and high protein concentrations. Further optimization with a combination of additives led to the generation of SpaE crystals in an orthorhombic form that diffracted to a higher resolution of 1.5 Å. To expedite structure determination by SAD phasing, selenium-substituted (orthorhombic) SpaE crystals were grown and X-ray diffraction data were collected to 1.8 Å resolution.

scholarly journals Characterization of an Alkaline GH49 Dextranase from Marine Bacterium Arthrobacter oxydans KQ11 and Its Application in the Preparation of Isomalto-Oligosaccharide

Marine Drugs ◽  
2019 ◽  
Vol 17 (8) ◽  
pp. 479 ◽  
Author(s):  
Hongfei Liu ◽  
Wei Ren ◽  
Mingsheng Ly ◽  
Haifeng Li ◽  
Shujun Wang
Keyword(s):  
Escherichia Coli ◽  
Marine Bacteria ◽  
Recombinant Expression ◽  
Bifidobacterium Longum ◽  
Lactobacillus Rhamnosus ◽  
Km Value ◽  
Tlc Analysis ◽  
Layer Chromatography ◽  
Arthrobacter Oxydans

A GH49 dextranase gene DexKQ was cloned from marine bacteria Arthrobacter oxydans KQ11. It was recombinantly expressed using an Escherichia coli system. Recombinant DexKQ dextranase of 66 kDa exhibited the highest catalytic activity at pH 9.0 and 55 °C. kcat/Km of recombinant DexKQ at the optimum condition reached 3.03 s−1 μM−1, which was six times that of commercial dextranase (0.5 s−1 μM−1). DexKQ possessed a Km value of 67.99 µM against dextran T70 substrate with 70 kDa molecular weight. Thin-layer chromatography (TLC) analysis showed that main hydrolysis end products were isomalto-oligosaccharide (IMO) including isomaltotetraose, isomaltopantose, and isomaltohexaose. When compared with glucose, IMO could significantly improve growth of Bifidobacterium longum and Lactobacillus rhamnosus and inhibit growth of Escherichia coli and Staphylococcus aureus. This is the first report of dextranase from marine bacteria concerning recombinant expression and application in isomalto-oligosaccharide preparation.

scholarly journals Crystallization and preliminary X-ray diffraction analysis of the periplasmic domain of theEscherichia coliaspartate receptor Tar and its complex with aspartate

2014 ◽  
Vol 70 (9) ◽  
pp. 1219-1223 ◽  
Author(s):  
Takeshi Mise ◽  
Hideyuki Matsunami ◽  
Fadel A. Samatey ◽  
Ichiro N. Maruyama
Keyword(s):  
Escherichia Coli ◽  
Sodium Chloride ◽  
Molecular Mechanisms ◽  
Bacterial Chemotaxis ◽  
Cell Surface Receptor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Space Groups ◽  
Surface Receptor ◽  
Periplasmic Domain

The cell-surface receptor Tar mediates bacterial chemotaxis toward an attractant, aspartate (Asp), and away from a repellent, Ni2+. To understand the molecular mechanisms underlying the induction of Tar activity by its ligands, theEscherichia coliTar periplasmic domain with and without bound aspartate (Asp-Tar and apo-Tar, respectively) were each crystallized in two different forms. Using ammonium sulfate as a precipitant, crystals of apo-Tar1 and Asp-Tar1 were grown and diffracted to resolutions of 2.10 and 2.40 Å, respectively. Alternatively, using sodium chloride as a precipitant, crystals of apo-Tar2 and Asp-Tar2 were grown and diffracted to resolutions of 1.95 and 1.58 Å, respectively. Crystals of apo-Tar1 and Asp-Tar1 adopted space groupP41212, while those of apo-Tar2 and Asp-Tar2 adopted space groupsP212121andC2, respectively.

scholarly journals Identification of Breast Cancer-Associated Lipids in Scalp Hair

2012 ◽  
Vol 6 ◽  
pp. BCBCR.S9607 ◽  
Author(s):  
Dharmica A.H. Mistry ◽  
Joseph Haklani ◽  
Peter W. French
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Biological Samples ◽  
Molecular Mechanisms ◽  
Scalp Hair ◽  
Breast Cancer Patients ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray

A correlation between the presence of breast cancer and a change in the synchrotron-generated X-ray diffraction (XRD) pattern of hair has been reported in several publications by different groups, and on average XRD-based assays detect around 75% of breast cancer patients in blinded studies. To date, the molecular mechanisms leading to this alteration are largely unknown. We have determined that the alteration is likely to be due to the presence of one or more breast cancer-associated phospholipids. Further characterization of these lipids could be used to develop a novel, sensitive and specific screening test for breast cancer, based on hair initially, and potentially extendable to other biological samples.

scholarly journals Purification, crystallization, crystallographic analysis and phasing of the CRISPR-associated protein Csm2 from Thermotoga maritima

2015 ◽  
Vol 71 (10) ◽  
pp. 1223-1227 ◽  
Author(s):  
Gloria Gallo ◽  
Gilles Augusto ◽  
Giulliana Rangel ◽  
André Zelanis ◽  
Marcelo A. Mori ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Thermotoga Maritima ◽  
Recombinant Expression ◽  
Crystallographic Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Type Iiia ◽  
Associated Proteins ◽  
Sad Phasing ◽  
Interference Mechanism

The clusters of regularly interspaced short palindromic repeats (CRISPR)–CRISPR-associated proteins (Cas) system consists of an intriguing machinery of proteins that confer bacteria and archaea with immunity against phages and plasmids via an RNA-guided interference mechanism. Here, the cloning, recombinant expression in Escherichia coli BL21 (DE3), purification, crystallization and preliminary X-ray diffraction analysis of Csm2 from Thermotoga maritima are reported. Csm2 is thought to be a component of an important protein complex of the type IIIA CRISPR–Cas system, which is involved in the CRISPR–Cas RNA-guided interference pathway. The structure of Csm2 was solved via cadmium single-wavelength anomalous diffraction (Cd-SAD) phasing. Owing to its involvement in the CRISPR–Cas system, the crystal structure of this protein could be of importance in elucidating the mechanism of type IIIA CRISPR–Cas systems in bacteria and archaea.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

High Resolution Replication of Organoclay Surfaces

1982 ◽  
Vol 40 ◽  
pp. 576-577
Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys
Keyword(s):  
Clay Mineral ◽  
Organic Molecule ◽  
Organic Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Naturally Occurring ◽  
Silicate Layers ◽  
Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

Synthesis and characterization of TiN / Ti / AISI 410 coatings

2018 ◽  
Vol 2 (1) ◽  
pp. 7
Author(s):  
S Chirino ◽  
Jaime Diaz ◽  
N Monteblanco ◽  
E Valderrama
Keyword(s):  
Synthesis And Characterization ◽  
Photoemission Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Columnar Grains ◽  
Tin Thin Films ◽  
Steel Aisi ◽  
Interacting Surfaces ◽  
Stainless Steel Aisi

The synthesis and characterization of Ti and TiN thin films of different thicknesses was carried out on a martensitic stainless steel AISI 410 substrate used for tool manufacturing. The mechanical parameters between the interacting surfaces such as thickness, adhesion and hardness were measured. By means of the scanning electron microscope (SEM) the superficial morphology of the Ti/TiN interface was observed, finding that the growth was of columnar grains and by means of EDAX the existence of titanium was verified.  Using X-ray diffraction (XRD) it was possible to observe the presence of residual stresses (~ -3.1 GPa) due to the different crystalline phases in the coating. Under X-ray photoemission spectroscopy (XPS) it was possible to observe the molecular chemical composition of the coating surface, being Ti-N, Ti-N-O and Ti-O the predominant ones.

Studies on the Preparation, Characterization and Solubility of -Cyclodextrin-Roxythromycin Inclusion Complexes

2009 ◽  
Vol 2 (2) ◽  
pp. 523-530
Author(s):  
D. Nagasamy Venkatesh ◽  
S. Karthick ◽  
M. Umesh ◽  
G. Vivek ◽  
R.M. Valliappan ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Inclusion Complexes ◽  
Phase Solubility ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Ir Studies ◽  
Poorly Soluble ◽  
Poorly Soluble Drug

Roxythromycin/ β-cyclodextrin (Roxy/ β-CD) dispersions were prepared with a view to study the influence of β-CD on the solubility and dissolution rate of this poorly soluble drug. Phase-solubility profile indicated that the solubility of roxythromycin was significantly increased in the presence of β-cyclodextrin and was classified as AL-type, indicating the 1:1 stoichiometric inclusion complexes. Physical characterization of the prepared systems was carried out by differential scanning calorimetry (DSC), X-ray diffraction studies (XRD) and IR studies. Solid state characterization of the drug β-CD binary system using XRD, FTIR and DSC revealed distinct loss of drug crystallinity in the formulation, ostensibly accounting for enhancement of dissolution rate.

New Coordination Compounds of Fe(III) with Organic Ligands

2009 ◽  
Vol 59 (12) ◽  
Author(s):  
Mihaela Flondor ◽  
Ioan Rosca ◽  
Doina Sibiescu ◽  
Mihaela-Aurelia Vizitiu ◽  
Daniel-Mircea Sutiman ◽  
...  
Keyword(s):  
Chemical Analysis ◽  
Complex Compounds ◽  
Organic Ligands ◽  
X Ray Diffraction ◽  
X Ray ◽  
Elemental Chemical Analysis ◽  
Structural Formulae ◽  
Paramagnetic Properties

In this paper the synthesis and the study of some complex compounds of Fe(III) with ligands derived from: 2-(4-chloro-phenylsulfanyl)-1-(2-hydroxy-3,5-diiodo-phenyl)-ethanone (HL1), 1-(3,5-dibromo-2-hydroxy-phenyl)-2-phenylsulfanyl-ethanone(HL2), and 2-(4-chloro-phenylsulfanyl)-1-(3,5-dibromo-2-hydroxy-phenyl)-ethanone (HL3) is presented. The characterization of these complexes is based on method as: the elemental chemical analysis, IR and ESR spectroscopy, M�ssbauer, the thermogravimetric analysis and X-ray diffraction. Study of the IR and chemical analysis has evidenced that the precipitates form are a complexes and the combination ratio of M:L is 1:2. The central atoms of Fe(III) presented paramagnetic properties and a octaedric hybridization. Starting from this precipitation reactions, a method for the gravimetric determination of Fe(III) with this organic ligands has been possible. Based on the experimental data on literature indications, the structural formulae of the complex compounds are assigned.

Sign in / Sign up

Export Citation Format

Share Document