scholarly journals Crystallization and preliminary X-ray diffraction studies of the GhKCH2 motor domain: alteration of pH significantly improved the quality of the crystals

Author(s):  
Xinghua Qin ◽  
Ziwei Chen ◽  
Tao Xu ◽  
Ping Li ◽  
Guoqin Liu

GhKCH2, a member of the kinesin superfamily, is a plant-specific microtubule-dependent motor protein from cotton with the ability to bind to both microtubules and microfilaments. Here, the motor domain of GhKCH2 (GhKCH2MD; amino acids 371–748) was overexpressed inEscherichia coli, purified and crystallized using the sitting-drop vapour-diffusion method. The pH of the crystallization buffer was shown to have a significant effect on the crystal morphology and diffraction quality. The crystals belonged to space groupP212121, with unit-cell parametersa= 60.7,b= 78.6,c= 162.8 Å, α = β = γ = 90°. The Matthews coefficient and solvent content were calculated as 2.27 Å3 Da−1and 45.87%, respectively. X-ray diffraction data for GhKCH2MD were collected on beamline BL17U1 at Shanghai Synchrotron Radiation Facility and processed to 2.8 Å resolution.

Author(s):  
Natalia Pakharukova ◽  
Minna Tuittila ◽  
Sari Paavilainen ◽  
Anton Zavialov

The attachment of many Gram-negative pathogens to biotic and abiotic surfaces is mediated by fimbrial adhesins, which are assembledviathe classical, alternative and archaic chaperone–usher (CU) pathways. The archaic CU fimbrial adhesins have the widest phylogenetic distribution, yet very little is known about their structure and mechanism of assembly. To elucidate the biogenesis of archaic CU systems, structural analysis of the Csu fimbriae, which are used byAcinetobacter baumanniito form stable biofilms and cause nosocomial infection, was focused on. The major fimbriae subunit CsuA/B complexed with the CsuC chaperone was purified from the periplasm ofEscherichia colicells co-expressing CsuA/B and CsuC, and the complex was crystallized in PEG 3350 solution using the hanging-drop vapour-diffusion method. Selenomethionine-labelled CsuC–CsuA/B complex was purified and crystallized under the same conditions. The crystals diffracted to 2.40 Å resolution and belonged to the hexagonal space groupP6422, with unit-cell parametersa=b= 94.71,c = 187.05 Å, α = β = 90, γ = 120°. Initial phases were derived from a single anomalous diffraction (SAD) experiment using the selenomethionine derivative.


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.


Author(s):  
Lilan Zhang ◽  
Puya Zhao ◽  
Chun-Chi Chen ◽  
Chun-Hsiang Huang ◽  
Tzu-Ping Ko ◽  
...  

β-1,3–1,4-Glucanases catalyze the specific hydrolysis of internal β-1,4-glycosidic bonds adjacent to the 3-O-substituted glucose residues in mixed-linked β-glucans. The thermophilic glycoside hydrolase CtGlu16A fromClostridium thermocellumexhibits superior thermal profiles, high specific activity and broad pH adaptability. Here, the catalytic domain of CtGlu16A was expressed inEscherichia coli, purified and crystallized in the trigonal space groupP3121, with unit-cell parametersa=b= 74.5,c= 182.9 Å, by the sitting-drop vapour-diffusion method and diffracted to 1.95 Å resolution. The crystal contains two protein molecules in an asymmetric unit. Further structural determination and refinement are in progress.


Author(s):  
Lihan Zhang ◽  
Jing Chen ◽  
Takahiro Mori ◽  
Yan Yan ◽  
Wen Liu ◽  
...  

AntE fromStreptomycessp. NRRL 2288 is a crotonyl-CoA carboxylase/reductase that catalyzes the reductive carboxylation of various α,β-unsaturated acyl-CoAs to provide the building block at the C7 position for antimycin A biosynthesis. Recombinant AntE expressed inEscherichia coliwas crystallized by the sitting-drop vapour-diffusion method. The crystals belonged to space groupI222 orI212121, with unit-cell parametersa= 76.4,b= 96.7,c= 129.6 Å, α = β = γ = 90.0°. A diffraction data set was collected at the KEK Photon Factory to 2.29 Å resolution.


2000 ◽  
Vol 56 (1) ◽  
pp. 64-66 ◽  
Author(s):  
B. Gopal ◽  
R. A. Cox ◽  
M. J. Colston ◽  
G. G. Dodson ◽  
S. J. Smerdon ◽  
...  

N-utilizing substance B (NusB) is a protein which forms part of a complex assembly in transcriptional antitermination in Mycobacterium tuberculosis. It forms a heterodimer with the product of the NusE gene (identical to the ribosomal protein S10) and mediates the process of transcriptional antitermination by forming the core complex with the nut site of the ribosomal RNA along with other protein factors. NusB has been cloned and overexpressed in Escherichia coli and crystallized using the hanging-drop vapour-diffusion method. The space group is P212121, with unit-cell parameters a = 46.6, b = 64.2, c = 90.1 Å. A native data set complete to 1.6 Å resolution has been collected from a single crystal.


2014 ◽  
Vol 70 (12) ◽  
pp. 1683-1687 ◽  
Author(s):  
Hanbin Jeong ◽  
Byoung Heon Kang ◽  
Changwook Lee

Hsp90 is a molecular chaperone responsible for the assembly and regulation of many cellular client proteins. In particular, Trap1, a mitochondrial Hsp90 homologue, plays a pivotal role in maintaining mitochondrial integrity, protecting against apoptosis in cancer cells. The N (N-terminal)-M (middle) domain of human Trap1 was crystallized in complex with Hsp90 inhibitors (PU-H71 and BIIB-021) by the hanging-drop vapour-diffusion method at pH 6.5 and 293 K using 15% PEG 8K as a precipitant. Diffraction data were collected from crystals of the Trap1–PU-H71 (2.7 Å) and Trap1–BIIB-021 (3.1 Å) complexes to high resolution at a synchrotron-radiation source. Preliminary X-ray diffraction analysis revealed that both crystals belonged to space groupP41212 orP43212, with unit-cell parametersa=b= 69.2,c= 252.5 Å, and contained one molecule per asymmetric unit according to Matthews coefficient calculations.


2014 ◽  
Vol 70 (9) ◽  
pp. 1211-1214 ◽  
Author(s):  
Fang-Fang Chen ◽  
Yu-Yung Chang ◽  
Chao-Cheng Cho ◽  
Chun-Hua Hsu

Plant-type APS reductase (APR), which catalyzes the reduction of activated sulfate to sulfite in plants, consists of a reductase domain and a C-terminal redox domain showing sequence homology to thioredoxin but possessing the activity of glutaredoxin. In order to understand the structural and biochemical properties of the redox domain of plant-type APS reductase, the C-terminal domain of APR1 (APR1C) fromArabidopsis thalianawas crystallized using the sitting-drop vapour-diffusion method. X-ray diffraction data were collected to a resolution of 2.70 Å on the SPXF beamline BL13B1 at the NSRRC, Taiwan. The crystals belonged to space groupP43212 orP41212, with unit-cell parametersa=b= 58.2,c= 86.7 Å. With one molecule per asymmetric unit, the crystal volume per unit protein weight (VM) is 2.64 Å3 Da−1, which corresponds to a solvent content of approximately 53.49%. Further structure-based functional studies of APR1C would extend knowledge of the molecular mechanism and regulation of APR.


Author(s):  
Hackwon Do ◽  
Il-Sup Kim ◽  
Young-Saeng Kim ◽  
Sun-Young Shin ◽  
Jin-Ju Kim ◽  
...  

Dehydroascorbate reductase fromOryza sativaL.japonica(OsDHAR), a key enzyme in the regeneration of vitamin C, maintains reduced pools of ascorbic acid to detoxify reactive oxygen species. In previous studies, the overexpression of OsDHAR in transgenic rice increased grain yield and biomass as well as the amount of ascorbate, suggesting that ascorbate levels are directly associated with crop production in rice. Hence, it has been speculated that the increased level of antioxidants generated by OsDHAR protects rice from oxidative damage and increases the yield of rice grains. However, the crystal structure and detailed mechanisms of this important enzyme need to be further elucidated. In this study, recombinant OsDHAR protein was purified and crystallized using the sitting-drop vapour-diffusion method at pH 8.0 and 298 K. Plate-shaped crystals were obtained using 0.15 Mpotassium bromide, 30%(w/v) PEG MME 2000 as a precipitant, and the crystals diffracted to a resolution of 1.9 Å on beamline 5C at the Pohang Accelerator Laboratory. The X-ray diffraction data indicated that the crystal contained one OsDHAR molecule in the asymmetric unit and belonged to space groupP21with unit-cell parametersa= 47.03,b= 48.38,c= 51.83 Å, β = 107.41°.


Author(s):  
Dan Huang ◽  
Yanan Zhang ◽  
Yanxiang Zhao ◽  
Junfeng Liu ◽  
You-Liang Peng

RGA5-A, a component of the Pia resistance-protein complex (RGA4/RGA5-A) fromOryza sativaL.japonica, has the ability to interact physically with the effector protein AVR-Pia fromMagnaporthe oryzaeviaits effector-interaction domain RGA5-A_S. The interaction between RGA5-A and AVR-Pia relieves the repression of RGA4, leading to AVR-independent cell death by the freed RGA4. To further understand the details of this interaction, the effector-interaction domain RGA5-A_S was expressed inEscherichia coliand purified to homogeneity. The purified recombinant protein His-RGA5-A_S was successfully crystallized using the sitting-drop vapour-diffusion method. A single crystal obtained using 0.2Mammonium citrate, 25%(w/v) PEG 3350 diffracted to 2.43 Å resolution. It belonged to space groupP4122 orP4322, with unit-cell parametersa=b= 55.2,c= 78.2 Å, α = β = γ = 90°.


Author(s):  
Hui Li ◽  
Hongyan Zhao ◽  
Laikuan Zhu ◽  
Lihua Hong ◽  
Hong Zhang ◽  
...  

S-Ribosylhomocysteinase (LuxS) encoded by theluxSgene fromStreptococcus mutansplays a crucial role in the quorum-sensing system. LuxS was solubly expressed inEscherichia coliwith high yield. The purity of the purified target protein, which was identified by SDS–PAGE and MALDI–TOF MS analysis, was >95%. The protein was crystallized using the hanging-drop vapour-diffusion method with PEG 3350 as the primary precipitant. X-ray diffraction data were collected at Beijing Synchrotron Radiation Facility (BSRF). Diffraction by the crystal extended to 2.4 Å resolution and the crystal belonged to space groupC2221, with unit-cell parametersa= 55.3,b= 148.7,c= 82.8 Å.


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