scholarly journals Data collection with a tailored X-ray beam size at 2.69 Å wavelength (4.6 keV): sulfur SAD phasing of Cdc23Nterm

2016 ◽  
Vol 72 (3) ◽  
pp. 403-412 ◽  
Author(s):  
Michele Cianci ◽  
Matthew R. Groves ◽  
David Barford ◽  
Thomas R. Schneider
Keyword(s):  
Data Collection ◽  
Anaphase Promoting Complex ◽  
X Ray ◽  
Cell Parameters ◽  
Structure Solution ◽  
Sad Phasing ◽  
A Subunit ◽  
Anomalous Signal ◽  
Crystal Twinning ◽  
Methionine Residues

The capability to reach wavelengths of up to 3.1 Å at the newly established EMBL P13 beamline at PETRA III, the new third-generation synchrotron at DESY in Hamburg, provides the opportunity to explore very long wavelengths to harness the sulfur anomalous signal for phase determination. Data collection at λ = 2.69 Å (4.6 keV) allowed the crystal structure determination by sulfur SAD phasing of Cdc23Nterm, a subunit of the multimeric anaphase-promoting complex (APC/C). At this energy, Cdc23Ntermhas an expected Bijvoet ratio 〈|Fanom|〉/〈F〉 of 2.2%, with 282 residues, including six cysteines and five methionine residues, and two molecules in the asymmetric unit (65.4 kDa; 12 Cys and ten Met residues). Selectively illuminating two separate portions of the same crystal with an X-ray beam of 50 µm in diameter allowed crystal twinning to be overcome. The crystals diffracted to 3.1 Å resolution, with unit-cell parametersa=b= 61.2,c = 151.5 Å, and belonged to space groupP43. The refined structure to 3.1 Å resolution has anRfactor of 18.7% and anRfreeof 25.9%. This paper reports the structure solution, related methods and a discussion of the instrumentation.

scholarly journals Optimization in S-SAD phasing - difference between solved and unsolved structure

2014 ◽  
Vol 70 (a1) ◽  
pp. C613-C613
Author(s):  
Jan Stránský ◽  
Tomáš Kovaľ ◽  
Lars Østergaard ◽  
Jarmila Dušková ◽  
Tereza Skálová ◽  
...  
Keyword(s):  
Data Processing ◽  
De Novo ◽  
Protein Structures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Solution ◽  
Sad Phasing ◽  
Optimal Values ◽  
Grant Agency ◽  
Intensity Reading

Development of X-ray diffraction technologies have made de novo phasing of protein structures by single-wavelength anomalous dispersion by sulphur (S-SAD) more common. As anomalous differences in the sulphur atomic factors are in the order of errors of measurement, careful intensity reading and data processing are crucial. S-SAD was used for de novo phasing of a small 12 kDa protein with 4 sulphur atoms per molecule at 2.3 Å, where the data did not enable a straightforward structure solution. Data processing was performed using XDS [1] and scaling using XSCALE. The sulphur substructure was determined by SHELXD [2] and phases were obtained from SHELXE [2]. Both algorithms strongly depend on input parameters and default values did not lead to the correct phases. Therefore a systematic search of optimal values of several parameters was used to find a solution. This method helped to confirm sulphur substructure and to differentiate the handedness of the solutions. Moreover, a script for comfortable conversion of SHELX outputs to MTZ format was developed, using programmes included in the CCP4 package [3]. The previously unsolvable protein structure was successfully resolved with the described procedure. This work was supported by the Grant Agency of the Czech Technical University in Prague, (SGS13/219/OHK4/3T/14), the Czech Science Foundation (P302/11/0855), project BIOCEV CZ.1.05/1.1.00/02.0109 from the ERDF.

scholarly journals Data-collection strategy for challenging native SAD phasing

2016 ◽  
Vol 72 (3) ◽  
pp. 421-429 ◽  
Author(s):  
Vincent Olieric ◽  
Tobias Weinert ◽  
Aaron D. Finke ◽  
Carolin Anders ◽  
Dianfan Li ◽  
...  
Keyword(s):  
Data Collection ◽  
Data Sets ◽  
Yield Data ◽  
Guide Rna ◽  
Multiple Data ◽  
Data Collection Strategy ◽  
Sad Phasing ◽  
Anomalous Signal ◽  
Multiple Data Sets ◽  
Low X

Recent improvements in data-collection strategies have pushed the limits of native SAD (single-wavelength anomalous diffraction) phasing, a method that uses the weak anomalous signal of light elements naturally present in macromolecules. These involve the merging of multiple data sets from either multiple crystals or from a single crystal collected in multiple orientations at a low X-ray dose. Both approaches yield data of high multiplicity while minimizing radiation damage and systematic error, thus ensuring accurate measurements of the anomalous differences. Here, the combined use of these two strategies is described to solve cases of native SAD phasing that were particular challenges: the integral membrane diacylglycerol kinase (DgkA) with a low Bijvoet ratio of 1% and the large 200 kDa complex of the CRISPR-associated endonuclease (Cas9) bound to guide RNA and target DNA crystallized in the low-symmetry space groupC2. The optimal native SAD data-collection strategy based on systematic measurements performed on the 266 kDa multiprotein/multiligand tubulin complex is discussed.

A solution-free crystal-mounting platform for native SAD

2020 ◽  
Vol 76 (10) ◽  
pp. 938-945
Author(s):  
Jian Yu ◽  
Akira Shinoda ◽  
Koji Kato ◽  
Isao Tanaka ◽  
Min Yao
Keyword(s):  
Data Collection ◽  
Nucleic Acids ◽  
Protein Structures ◽  
Anomalous Scattering ◽  
X Rays ◽  
Long Wavelength ◽  
Light Atoms ◽  
Sad Phasing ◽  
Anomalous Signal

The native SAD phasing method uses the anomalous scattering signals from the S atoms contained in most proteins, the P atoms in nucleic acids or other light atoms derived from the solution used for crystallization. These signals are very weak and careful data collection is required, which makes this method very difficult. One way to enhance the anomalous signal is to use long-wavelength X-rays; however, these wavelengths are more strongly absorbed by the materials in the pathway. Therefore, a crystal-mounting platform for native SAD data collection that removes solution around the crystals has been developed. This platform includes a novel solution-free mounting tool and an automatic robot, which extracts the surrounding solution, flash-cools the crystal and inserts the loop into a UniPuck cassette for use in the synchrotron. Eight protein structures (including two new structures) have been successfully solved by the native SAD method from crystals prepared using this platform.

scholarly journals Crystallization and preliminary X-ray analysis of the NAD+-reducing [NiFe] hydrogenase fromHydrogenophilus thermoluteolusTH-1

2015 ◽  
Vol 71 (1) ◽  
pp. 96-99 ◽  
Author(s):  
Midori Taketa ◽  
Hanae Nakagawa ◽  
Mao Habukawa ◽  
Hisao Osuka ◽  
Kiyohito Kihira ◽  
...  
Keyword(s):  
Diffusion Method ◽  
Asymmetric Unit ◽  
Dispersion Method ◽  
Unit Cell Parameters ◽  
Solvent Content ◽  
X Ray ◽  
Cell Parameters ◽  
Vapour Diffusion ◽  
Anomalous Signal ◽  
Th 1

NAD+-reducing [NiFe] hydrogenases catalyze the oxidoreduction of dihydrogen concomitant with the interconversion of NAD+and NADH. Here, the isolation, purification and crystallization of the NAD+-reducing [NiFe] hydrogenase fromHydrogenophilus thermoluteolusTH-1 are reported. Crystals of the NAD+-reducing [NiFe] hydrogenase were obtained within one week from a solution containing polyethylene glycol using the sitting-drop vapour-diffusion method and micro-seeding. The crystal diffracted to 2.58 Å resolution and belonged to space groupC2, with unit-cell parametersa= 131.43,b= 189.71,c= 124.59 Å, β = 109.42°. Assuming the presence of two NAD+-reducing [NiFe] hydrogenase molecules in the asymmetric unit,VMwas calculated to be 2.2 Å3 Da−1, which corresponds to a solvent content of 43%. Initial phases were determined by the single-wavelength anomalous dispersion method using the anomalous signal from the Fe atoms.

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

2019 ◽  
Vol 75 (12) ◽  
pp. 731-737 ◽  
Author(s):  
Abhin Kumar Megta ◽  
Airi Palva ◽  
Ingemar von Ossowski ◽  
Vengadesan Krishnan
Keyword(s):  
Lactobacillus Rhamnosus ◽  
Crystal Form ◽  
Data Sets ◽  
Structural Factors ◽  
Lysine Methylation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
Dual Functional ◽  
Anomalous Signal

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.

scholarly journals Successful data recovery from oscillation photographs containing strong polycrystalline diffraction rings from an unknown small-molecule contaminant: preliminary structure solution ofSalmonella typhimuriumpyridoxal kinase (PdxK)

2014 ◽  
Vol 70 (4) ◽  
pp. 526-529 ◽  
Author(s):  
G. Deka ◽  
J. N. Kalyani ◽  
J. F. Benazir ◽  
H. S. Savithri ◽  
M. R. N. Murthy
Keyword(s):  
Small Molecule ◽  
Vitamin B ◽  
Molecular Replacement ◽  
X Ray Diffraction ◽  
Pyridoxal Kinase ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
E Coli ◽  
Structure Solution

Pyridoxal kinase (PdxK; EC 2.7.1.35) belongs to the phosphotransferase family of enzymes and catalyzes the conversion of the three active forms of vitamin B6, pyridoxine, pyridoxal and pyridoxamine, to their phosphorylated forms and thereby plays a key role in pyridoxal 5′-phosphate salvage. In the present study, pyridoxal kinase fromSalmonella typhimuriumwas cloned and overexpressed inEscherichia coli, purified using Ni–NTA affinity chromatography and crystallized. X-ray diffraction data were collected to 2.6 Å resolution at 100 K. The crystal belonged to the primitive orthorhombic space groupP212121, with unit-cell parametersa= 65.11,b= 72.89,c= 107.52 Å. The data quality obtained by routine processing was poor owing to the presence of strong diffraction rings caused by a polycrystalline material of an unknown small molecule in all oscillation images. Excluding the reflections close to powder/polycrystalline rings provided data of sufficient quality for structure determination. A preliminary structure solution has been obtained by molecular replacement with thePhaserprogram in theCCP4 suite usingE. colipyridoxal kinase (PDB entry 2ddm) as the phasing model. Further refinement and analysis of the structure are likely to provide valuable insights into catalysis by pyridoxal kinases.

scholarly journals Advancing Native-SAD Phasing at Synchrotron with 13 Real-life Case Studies

2014 ◽  
Vol 70 (a1) ◽  
pp. C601-C601
Author(s):  
Meitian Wang
Keyword(s):  
Data Collection ◽  
Single Crystal ◽  
Measurement Errors ◽  
Model Building ◽  
De Novo ◽  
Real Life ◽  
Data Sets ◽  
X Ray ◽  
Recent Developments ◽  
Sad Phasing

The key step in elucidating de novo 3D X-ray structures relies on the incorporation of heavy elements into proteins or crystals. Selenomethionine incorporation or heavy metal derivatization are however not always possible and require additional efforts. Exploiting anomalous signals from intrinsically present elements like S, P, and Ca2+ from proteins and nucleic acids, as well as Cl-, SO42-, and PO42- from crystallization solutions, is therefore an appealing alternative. Such a method has been shown to be valid by collecting data from several crystals and combining them(1). Recent developments at macromolecular crystallography beamlines are however pushing the limits of what could be obtained out of a single crystal. Here we introduce a novel data collection routine for native-SAD phasing, which distributes tolerable X-ray life-doses to very high multiplicity X-ray diffraction data sets measured at 6 keV energy and at different crystal orientations on a single crystal. This allows the extraction of weak anomalous signals reliably by reducing both systematic and random measurement errors. The data collection method has been applied successfully to thirteen real-life examples including membrane proteins, a protein/DNA complex, and a large protein complex. In addition to de novo structure determination, we advocate such a data collection protocol for molecular replacement solvable structures where unbiased phase information is crucial in objective map interpretation and model building, especially for medium and low-resolution cases.

Structure of sodiumpara-hydroxybenzoate, NaO2C–C6H4OH by powder diffraction: application of a phenomenological model of anisotropic peak width

1999 ◽  
Vol 32 (4) ◽  
pp. 761-769 ◽  
Author(s):  
R. E. Dinnebier ◽  
R. Von Dreele ◽  
P. W. Stephens ◽  
S. Jelonek ◽  
J. Sieler
Keyword(s):  
Powder Diffraction ◽  
Phenomenological Model ◽  
Hydrogen Bridge ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Structure Solution ◽  
Diffraction Angle ◽  
Peak Widths ◽  
Additional Hydrogen

Theab initiostructure solution of sodiumpara-hydroxybenzoate from high-resolution X-ray powder diffraction data is reported. The compound is of interest with respect to understanding the mechanism of Kolbe–Schmitt type reactions. It crystallizes in space groupP21,Z= 2, with unit-cell parametersa= 16.0608 (3),b=  5.38291 (9),c=  3.63834 (6) Å, β =  92.8692 (5)° andV=  314.153 Å3. The compound consists of layers of distorted NaO6prisms perpendicular to theaaxis and phenol rings perpendicular to these layers pointing up and down. The molecular structure is held together by van der Waals forces between the phenyl groups of different layers and additional hydrogen-bridge bonding between the phenolate oxygen atoms. The sample showed powder peak widths which are not a smooth function of diffraction angle; a recently implemented phenomenological model was able to describe this effect sufficiently well to obtain excellent Rietveld fits to the data. The accuracy of modeling the data makes this one of the rare cases where the position of a hydrogen atom could be unambiguously determined by powder techniques.

scholarly journals Experimental evidence for the benefits of higher X-ray energies for macromolecular crystallography

2021 ◽  
Author(s):  
S. L. S. Storm ◽  
D. Axford ◽  
R. L. Owen
Keyword(s):  
High Resolution ◽  
Data Collection ◽  
High Energy ◽  
Limiting Factor ◽  
Macromolecular Crystallography ◽  
Resolution Limit ◽  
Energy Data ◽  
X Ray ◽  
Structure Solution ◽  
Unit Dose

AbstractX-ray induced radiation damage is a limiting factor for the macromolecular crystallographer and data must often be merged from many crystals to yield complete datasets for structure solution of challenging samples. Increasing the X-ray energy beyond the typical 10-15 keV range promises to provide an extension of crystal lifetime via an increase in diffraction efficiency. To date however hardware limitations have negated any possible gains. Through the first use of a Cadmium Telluride Eiger2 detector and a beamline optimised for high energy data collection, we show that at higher energies fewer crystals will be required to obtain complete data, as the diffracted intensity per unit dose increases by a factor of more than 3 between 12.4 and 25 keV. Additionally, those higher energy data provide more information, evidenced by an increase in high-resolution limit of up to 0.3 Å, pointing to a high energy future for synchrotron-based macromolecular crystallography.

scholarly journals Synchrotron microcrystal native-SAD phasing at a low energy

IUCrJ ◽  
2019 ◽  
Vol 6 (4) ◽  
pp. 532-542 ◽  
Author(s):  
Gongrui Guo ◽  
Ping Zhu ◽  
Martin R. Fuchs ◽  
Wuxian Shi ◽  
Babak Andi ◽  
...  
Keyword(s):  
Data Analysis ◽  
Data Collection ◽  
Diffraction Data ◽  
De Novo ◽  
Low Energy ◽  
Anomalous Scattering ◽  
Free Electron Lasers ◽  
X Ray ◽  
Structural Evaluation ◽  
Sad Phasing

De novo structural evaluation of native biomolecules from single-wavelength anomalous diffraction (SAD) is a challenge because of the weakness of the anomalous scattering. The anomalous scattering from relevant native elements – primarily sulfur in proteins and phosphorus in nucleic acids – increases as the X-ray energy decreases toward their K-edge transitions. Thus, measurements at a lowered X-ray energy are promising for making native SAD routine and robust. For microcrystals with sizes less than 10 µm, native-SAD phasing at synchrotron microdiffraction beamlines is even more challenging because of difficulties in sample manipulation, diffraction data collection and data analysis. Native-SAD analysis from microcrystals by using X-ray free-electron lasers has been demonstrated but has required use of thousands of thousands of microcrystals to achieve the necessary accuracy. Here it is shown that by exploitation of anomalous microdiffraction signals obtained at 5 keV, by the use of polyimide wellmounts, and by an iterative crystal and frame-rejection method, microcrystal native-SAD phasing is possible from as few as about 1 200 crystals. Our results show the utility of low-energy native-SAD phasing with microcrystals at synchrotron microdiffraction beamlines.

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