scholarly journals SpaB, an atypically adhesive basal pilin from the lactobacillar SpaCBA pilus: crystallization and X-ray diffraction analysis

Author(s):  
Abhin Kumar Megta ◽  
Airi Palva ◽  
Ingemar von Ossowski ◽  
Vengadesan Krishnan

The SpaB pilin is recognized as the basal subunit of the sortase-dependent SpaCBA pilus, which is known to be produced by the Gram-positive Lactobacillus rhamnosus GG, a gut-adapted commensal advocated to have health benefits. Despite seeming to function as an archetypal basal pilin by serving as the terminal subunit in pilus assembly, SpaB also assumes an atypical role as a mucoadhesive protein. To shed light on the structural factors that contribute to this dual functional behaviour, a recombinant form of the L. rhamnosus GG SpaB pilin was produced and purified for crystallization and X-ray diffraction experiments. The crystallization of SpaB remained particularly challenging until the implementation of a three-pronged crystallization approach involving C-terminal tail truncation, surface lysine methylation and magnesium additives. Ultimately, hexagonal crystals of SpaB were produced and were able to diffract to a resolution of 2.4 Å. This crystal form belonged to space group P6522 or P6122, with unit-cell parameters a = b = 51.53, c = 408.22 Å, α = β = 90.0, γ = 120.0°. Obtaining an interpretable electron-density map via single-wavelength anomalous diffraction (SAD) using iodide-derivative data sets did not succeed owing to the weak anomalous signal. As an alternative, attempts to provide phases by molecular replacement using the iodide-SAD data from SpaB and a collection of distant homology models (<28% sequence identity) are in progress.

Author(s):  
Fang Lu ◽  
Bei Zhang ◽  
Yong Liu ◽  
Ying Song ◽  
Gangxing Guo ◽  
...  

Phytases are phosphatases that hydrolyze phytates to less phosphorylatedmyo-inositol derivatives and inorganic phosphate. β-Propeller phytases, which are very diverse phytases with improved thermostability that are active at neutral and alkaline pH and have absolute substrate specificity, are ideal substitutes for other commercial phytases. PhyH-DI, a β-propeller phytase fromBacillussp. HJB17, was found to act synergistically with other single-domain phytases and can increase their efficiency in the hydrolysis of phytate. Crystals of native and selenomethionine-substituted PhyH-DI were obtained using the vapour-diffusion method in a condition consisting of 0.2 Msodium chloride, 0.1 MTris pH 8.5, 25%(w/v) PEG 3350 at 289 K. X-ray diffraction data were collected to 3.00 and 2.70 Å resolution, respectively, at 100 K. Native PhyH-DI crystals belonged to space groupC121, with unit-cell parametersa = 156.84,b = 45.54,c = 97.64 Å, α = 90.00, β = 125.86, γ = 90.00°. The asymmetric unit contained two molecules of PhyH-DI, with a corresponding Matthews coefficient of 2.17 Å3 Da−1and a solvent content of 43.26%. Crystals of selenomethionine-substituted PhyH-DI belonged to space groupC2221, with unit-cell parametersa = 94.71,b= 97.03,c= 69.16 Å, α = β = γ = 90.00°. The asymmetric unit contained one molecule of the protein, with a corresponding Matthews coefficient of 2.44 Å3 Da−1and a solvent content of 49.64%. Initial phases for PhyH-DI were obtained from SeMet SAD data sets. These data will be useful for further studies of the structure–function relationship of PhyH-DI.


2014 ◽  
Vol 70 (12) ◽  
pp. 1675-1682 ◽  
Author(s):  
Roie Dann ◽  
Shifra Lansky ◽  
Noa Lavid ◽  
Arie Zehavi ◽  
Valery Belakhov ◽  
...  

Geobacillus stearothermophilusT6 is a thermophilic bacterium that possesses an extensive hemicellulolytic system, including over 40 specific genes that are dedicated to this purpose. For the utilization of xylan, the bacterium uses an extracellular xylanase which degrades xylan to decorated xylo-oligomers that are imported into the cell. These oligomers are hydrolyzed by side-chain-cleaving enzymes such as arabinofuranosidases, acetylesterases and a glucuronidase, and finally by an intracellular xylanase and a number of β-xylosidases. One of these β-xylosidases is Xyn52B2, a GH52 enzyme that has already proved to be useful for various glycosynthesis applications. In addition to its demonstrated glycosynthase properties, interest in the structural aspects of Xyn52B2 stems from its special glycoside hydrolase family, GH52, the structures and mechanisms of which are only starting to be resolved. Here, the cloning, overexpression, purification and crystallization of Xyn52B2 are reported. The most suitable crystal form that has been obtained belonged to the orthorhombicP212121space group, with average unit-cell parametersa = 97.7,b= 119.1,c = 242.3 Å. Several X-ray diffraction data sets have been collected from flash-cooled crystals of this form, including the wild-type enzyme (3.70 Å resolution), the E335G catalytic mutant (2.95 Å resolution), a potential mercury derivative (2.15 Å resolution) and a selenomethionine derivative (3.90 Å resolution). These data are currently being used for detailed three-dimensional structure determination of the Xyn52B2 protein.


1999 ◽  
Vol 55 (9) ◽  
pp. 1616-1617
Author(s):  
I. Polikarpov ◽  
R. T. de Oliveira ◽  
J. Abrahão-Neto

L-Asparaginase is an enzyme which hydrolyzes asparagine to produce aspartic acid and ammonia. It is an effective chemotherapeutic drug, especially in the treatment of acute lymphoblastic leukaemia in children. The enzyme from Escherichia coli was crystallized in a new crystal form with space group C2, unit-cell parameters a = 76.3 (0), b = 134.6 (2), c = 64.8 (7) Å, β = 110.5 (1)° and a dimer in the asymmetric unit. Synchrotron-radiation diffraction data have been collected to 1.95 Å resolution.


Author(s):  
Tatyana N. Safonova ◽  
Nadezhda N. Mordkovich ◽  
Konstantin M. Polyakov ◽  
Valentin A. Manuvera ◽  
Vladimir P. Veiko ◽  
...  

Uridine phosphorylase (UDP, EC 2.4.2.3), a key enzyme in the pyrimidine salvage pathway, catalyses the reversible phosphorolysis of uridine to uracil and ribose 1-phosphate. The gene expression of UDP fromShewanella oneidensisMR-1 was performed in the recipient strainEscherichia coli. The UDP protein was crystallized on earth (in the free form and in complex with uridine as the substrate) by the hanging-drop vapour-diffusion method at 296 K and under microgravity conditions (in the free form) aboard the Russian Segment of the International Space Station by the capillary counter-diffusion method. The data sets were collected to a resolution of 1.9 Å from crystals of the free form grown on earth, 1.6 Å from crystals of the complex with uridine and 0.95 Å from crystals of the free form grown under microgravity. All crystals belong to the space groupP21and have similar unit-cell parameters. The crystal of uridine phosphorylase grown under microgravity diffracted to ultra-high resolution and gave high-quality X-ray diffraction data.


2015 ◽  
Vol 71 (5) ◽  
pp. 1095-1101 ◽  
Author(s):  
Manuela Gorgel ◽  
Andreas Bøggild ◽  
Jakob Jensen Ulstrup ◽  
Manfred S. Weiss ◽  
Uwe Müller ◽  
...  

Exploiting the anomalous signal of the intrinsic S atoms to phase a protein structure is advantageous, as ideally only a single well diffracting native crystal is required. However, sulfur is a weak anomalous scatterer at the typical wavelengths used for X-ray diffraction experiments, and therefore sulfur SAD data sets need to be recorded with a high multiplicity. In this study, the structure of a small pilin protein was determined by sulfur SAD despite several obstacles such as a low anomalous signal (a theoretical Bijvoet ratio of 0.9% at a wavelength of 1.8 Å), radiation damage-induced reduction of the cysteines and a multiplicity of only 5.5. The anomalous signal was improved by merging three data sets from different volumes of a single crystal, yielding a multiplicity of 17.5, and a sodium ion was added to the substructure of anomalous scatterers. In general, all data sets were balanced around the threshold values for a successful phasing strategy. In addition, a collection of statistics on structures from the PDB that were solved by sulfur SAD are presented and compared with the data. Looking at the quality indicatorRanom/Rp.i.m., an inconsistency in the documentation of the anomalousRfactor is noted and reported.


Author(s):  
Srinivasan Rengachari ◽  
Philipp Aschauer ◽  
Christian Sturm ◽  
Monika Oberer

The protein Yju3p is the orthologue of monoglyceride lipases in the yeastSaccharomyces cerevisiae. A soluble variant of this lipase termed s-Yju3p (38.3 kDa) was generated and purified to homogeneity by affinity and size-exclusion chromatography. s-Yju3p was crystallized in a vapour-diffusion setup at 293 K and a complete data set was collected to 2.4 Å resolution. The crystal form was orthorhombic (space groupP212121), with unit-cell parametersa= 77.2,b= 108.6,c= 167.7 Å. The asymmetric unit contained four molecules with a solvent content of 46.4%.


Author(s):  
Yasumitsu Sakamoto ◽  
Yoshiyuki Suzuki ◽  
Ippei Iizuka ◽  
Chika Tateoka ◽  
Saori Roppongi ◽  
...  

Dipeptidyl aminopeptidase BII fromPseudoxanthomonas mexicanaWO24 (DAP BII) is able to cleave a variety of dipeptides from the amino-terminus of substrate peptides. For crystallographic studies, DAP BII was overproduced inEscherichia coli, purified and crystallized using the hanging-drop vapour-diffusion method. X-ray diffraction data to 2.3 Å resolution were collected using an orthorhombic crystal form belonging to space groupP212121, with unit-cell parametersa= 76.55,b= 130.86,c= 170.87 Å. Structural analysis by the multi-wavelength anomalous diffraction method is in progress.


Author(s):  
Saori Roppongi ◽  
Chika Tateoka ◽  
Mayu Fujimoto ◽  
Ippei Iizuka ◽  
Saori Morisawa ◽  
...  

Dipeptidyl aminopeptidase IV (DAP IV or DPP IV) fromPseudoxanthomonas mexicanaWO24 (PmDAP IV) preferentially cleaves substrate peptides with Pro or Ala at the P1 position [NH2-P2-P1(Pro/Ala)-P1′-P2′…]. For crystallographic studies, the periplasmic form of PmDAP IV was overproduced inEscherichia coli, purified and crystallized in complex with the tripeptide Lys-Pro-Tyr using the hanging-drop vapour-diffusion method. Kinetic parameters of the purified enzyme against a synthetic substrate were also determined. X-ray diffraction data to 1.90 Å resolution were collected from a triclinic crystal form belonging to space groupP1, with unit-cell parametersa= 88.66,b= 104.49,c = 112.84 Å, α = 67.42, β = 68.83, γ = 65.46°. Initial phases were determined by the molecular-replacement method usingStenotrophomonas maltophiliaDPP IV (PDB entry 2ecf) as a template and refinement of the structure is in progress.


2020 ◽  
Vol 76 (4) ◽  
pp. 366-374 ◽  
Author(s):  
Fotini Karavassili ◽  
Alexandros Valmas ◽  
Maria Dimarogona ◽  
Anastasia E. Giannopoulou ◽  
Stavroula Fili ◽  
...  

In this study, the first crystal structure of a novel crystal form of human insulin bound to meta-cresol in an acidic environment is reported. The combination of single-crystal and powder X-ray diffraction crystallography led to the detection of a previously unknown monoclinic phase (P21). The structure was identified from the powder patterns and was solved using single-crystal diffraction data at 2.2 Å resolution. The unit-cell parameters at pH 6.1 are a = 47.66, b = 70.36, c = 84.75 Å, β = 105.21°. The structure consists of two insulin hexamers per asymmetric unit. The potential use of this insulin form in microcrystalline drugs is discussed.


Author(s):  
Yasumitsu Sakamoto ◽  
Yoshiyuki Suzuki ◽  
Ippei Iizuka ◽  
Chika Tateoka ◽  
Saori Roppongi ◽  
...  

Dipeptidyl peptidase 11 fromPorphyromonas gingivalis(PgDPP11) preferentially cleaves substrate peptides with Asp and Glu at the P1 position [NH2–P2–P1(Asp/Glu)–P1′–P2′…]. For crystallographic studies, PgDPP11 was overproduced inEscherichia coli, purified and crystallized using the hanging-drop vapour-diffusion method. X-ray diffraction data to 1.82 Å resolution were collected from an orthorhombic crystal form belonging to space groupC2221, with unit-cell parametersa= 99.33,b= 103.60,c= 177.33 Å. Structural analysis by the multi-wavelength anomalous diffraction method is in progress.


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