scholarly journals The hyperthermophilic cystathionine γ-synthase from the aerobic crenarchaeonSulfolobus tokodaii: expression, purification, crystallization and structural insights

Author(s):  
Dan Sato ◽  
Tomoo Shiba ◽  
Sae Mizuno ◽  
Ayaka Kawamura ◽  
Shoko Hanada ◽  
...  

Cystathionine γ-synthase (CGS; EC 2.5.1.48), a pyridoxal 5′-phosphate (PLP)-dependent enzyme, catalyzes the formation of cystathionine from an L-homoserine derivative and L-cysteine in the first step of the transsulfuration pathway. Recombinant CGS from the thermoacidophilic archaeonSulfolobus tokodaii(StCGS) was overexpressed inEscherichia coliand purified to homogeneity by heat treatment followed by hydroxyapatite and gel-filtration column chromatography. The purified enzyme shows higher enzymatic activity at 353 K under basic pH conditions compared with that at 293 K. Crystallization trials yielded three crystal forms from different temperature and pH conditions. Form I crystals (space groupP21; unit-cell parametersa= 58.4,b= 149.3,c= 90.2 Å, β = 108.9°) were obtained at 293 K under acidic pH conditions using 2-methyl-2,4-pentanediol as a precipitant, whereas under basic pH conditions the enzyme crystallized in form II at 293 K (space groupC2221; unit-cell parametersa= 117.7,b= 117.8,c= 251.3 Å) and in form II′ at 313 K (space groupC2221; unit-cell parametersa= 107.5,b= 127.7,c= 251.1 Å) using polyethylene glycol 3350 as a precipitant. X-ray diffraction data were collected to 2.2, 2.9 and 2.7 Å resolution for forms I, II and II′, respectively. Structural analysis of these crystal forms shows that the orientation of the bound PLP in form II is significantly different from that in form II′, suggesting that the change in orientation of PLP with temperature plays a role in the thermophilic enzymatic activity of StCGS.

Author(s):  
Jintang Lei ◽  
Xun Cai ◽  
Xiaodan Ma ◽  
Li Zhang ◽  
Yuwen Li ◽  
...  

The Bam machinery, which is highly conserved from bacteria to humans, is well recognized as the apparatus responsible for the insertion and folding of most outer membrane proteins in Gram-negative bacteria. InEscherichia coli, the Bam machinery consists of five components (i.e.BamA, BamB, BamC, BamD and BamE). In comparison, there are only four partners inHaemophilus influenzae: a BamB homologue is not found in its genome. In this study, the recombinant expression, purification, crystallization and preliminary X-ray diffraction analysis ofH. influenzaeBamD and BamCD complex are reported. The genes encoding BamC and BamD were cloned into a pET vector and expressed inE. coli. Affinity, ion-exchange and gel-filtration chromatography were used to obtain high-purity protein for further crystallographic characterization. Using the hanging-drop vapour-diffusion technique, BamD and BamCD protein crystals of suitable size were obtained using protein concentrations of 70 and 50 mg ml−1, respectively. Preliminary X-ray diffraction analysis showed that the BamD crystals diffracted to 4.0 Å resolution and belonged to space groupP212121, with unit-cell parametersa= 54.5,b= 130.5,c= 154.7 Å. The BamCD crystals diffracted to 3.8 Å resolution and belonged to space groupI212121, with unit-cell parametersa= 101.6,b= 114.1,c= 234.9 Å.


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.


1999 ◽  
Vol 55 (4) ◽  
pp. 907-909 ◽  
Author(s):  
Jun Masuda ◽  
Tetsuya Yamaguchi ◽  
Takamasa Tobimatsu ◽  
Tetsuo Toraya ◽  
Kyoko Suto ◽  
...  

Two crystal forms of Klebsiella oxytoca diol dehydratase complexed with cyanocobalamin have been obtained and preliminary crystallographic experiments have been performed. The crystals belong to two different space groups, depending on the crystallization conditions. One crystal (form I) belongs to space group P212121 with unit-cell parameters a = 76.2, b = 122.3, c = 209.6 Å, and diffracts to 2.2 Å resolution using an X-ray beam from a synchrotron radiation source. The other crystal (form II) belongs to space group P21 with unit-cell parameters a = 75.4, b = 132.7, c = 298.8 Å, β = 91.9°, and diffracts to 3.0 Å resolution. For the purpose of structure determination, a heavy-atom derivative search was carried out and some mercuric derivatives were found to be promising. Structure analysis by the multiple isomorphous replacement method is now under way.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Myroslava Horiacha ◽  
Galyna Nychyporuk ◽  
Rainer Pöttgen ◽  
Vasyl Zaremba

Abstract Phase formation in the solid solution TbNiIn1−x Ga x at 873 K was investigated in the full concentration range by means of powder X-ray diffraction and EDX analysis. The samples were synthesized by arc-melting of the pure metals with subsequent annealing at 873 K for one month. The influence of the substitution of indium by gallium on the type of structure and solubility was studied. The solubility ranges have been determined and changes of the unit cell parameters were calculated on the basis of powder X-ray diffraction data: TbNiIn1–0.4Ga0–0.6 (ZrNiAl-type structure, space group P 6 ‾ 2 m $P‾{6}2m$ , a = 0.74461(8)–0.72711(17) and c = 0.37976(5)–0.37469(8) nm); TbNiIn0.2–0Ga0.8–1.0 (TiNiSi-type structure, space group Pnma, а = 0.68950(11)–0.68830(12), b = 0.43053(9)–0.42974(6), с = 0.74186(10)–0.73486(13) nm). The crystal structures of TbNiGa (TiNiSi type, Pnma, a = 0.69140(5), b = 0.43047(7), c = 0.73553(8) nm, wR2=0.0414, 525 F 2 values, 21 variables), TbNiIn0.83(1)Ga0.17(1) (ZrNiAl type, P 6 ‾ 2 m $P‾{6}2m$ , a = 0.74043(6), c = 0.37789(3) nm, wR2 = 0.0293, 322 F 2 values, 16 variables) and TbNiIn0.12(2)Ga0.88(2) (TiNiSi type, Pnma, a = 0.69124(6), b = 0.43134(9), c = 0.74232(11) nm, wR2 = 0.0495, 516 F 2 values, 21 variables) have been determined. The characteristics of the solid solutions and the variations of the unit cell parameters are briefly discussed.


Minerals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 486 ◽  
Author(s):  
Andrey A. Zolotarev ◽  
Elena S. Zhitova ◽  
Maria G. Krzhizhanovskaya ◽  
Mikhail A. Rassomakhin ◽  
Vladimir V. Shilovskikh ◽  
...  

The technogenic mineral phases NH4MgCl3·6H2O and (NH4)2Fe3+Cl5·H2O from the burned dumps of the Chelyabinsk coal basin have been investigated by single-crystal X-ray diffraction, scanning electron microscopy and high-temperature powder X-ray diffraction. The NH4MgCl3·6H2O phase is monoclinic, space group C2/c, unit cell parameters a = 9.3091(9), b = 9.5353(7), c = 13.2941(12) Å, β = 90.089(8)° and V = 1180.05(18) Å3. The crystal structure of NH4MgCl3·6H2O was refined to R1 = 0.078 (wR2 = 0.185) on the basis of 1678 unique reflections. The (NH4)2Fe3+Cl5·H2O phase is orthorhombic, space group Pnma, unit cell parameters a = 13.725(2), b = 9.9365(16), c = 7.0370(11) Å and V = 959.7(3) Å3. The crystal structure of (NH4)2Fe3+Cl5·H2O was refined to R1 = 0.023 (wR2 = 0.066) on the basis of 2256 unique reflections. NH4MgCl3·6H2O is stable up to 90 °C and then transforms to the less hydrated phase isotypic to β-Rb(MnCl3)(H2O)2 (i.e., NH4MgCl3·2H2O), the latter phase being stable up to 150 °C. (NH4)2Fe3+Cl5·H2O is stable up to 120 °C and then transforms to an X-ray amorphous phase. Hydrogen bonds provide an important linkage between the main structural units and play the key role in determining structural stability and physical properties of the studied phases. The mineral phases NH4MgCl3·6H2O and (NH4)2Fe3+Cl5·H2O are isostructural with natural minerals novograblenovite and kremersite, respectively.


2020 ◽  
Vol 84 (4) ◽  
pp. 608-615
Author(s):  
Ian E. Grey ◽  
Emre Yoruk ◽  
Stéphanie Kodjikian ◽  
Holger Klein ◽  
Catherine Bougerol ◽  
...  

AbstractBulachite specimens from Cap Garonne, France, comprise two intimately mixed hydrated aluminium arsenate minerals with the same Al:As ratio of 2:1 and with different water contents. The crystal structures of both minerals have been solved using data from low-dose electron diffraction tomography combined with synchrotron powder X-ray diffraction. One of the minerals has the same powder X-ray diffraction pattern (PXRD) as for published bulachite. It has orthorhombic symmetry, space group Pnma with unit-cell parameters a = 15.3994(3), b = 17.6598(3), c = 7.8083(1) Å and Z = 4, with the formula [Al6(AsO4)3(OH)9(H2O)4]⋅2H2O. The second mineral is a higher hydrate with composition [Al6(AsO4)3(OH)9(H2O)4]⋅8H2O. It has the same Pnma space group and unit-cell parameters a = 19.855(4), b = 17.6933(11) and c = 7.7799(5) Å i.e. almost the same b and c parameters but a much larger a parameter. The structures are based on polyhedral layers, parallel to (100), of composition [Al6(AsO4)3(OH)9(H2O)4] and with H-bonded H2O between the layers. The layers contain [001] spiral chains of edge-shared octahedra, decorated with corner connected AsO4 tetrahedra that are the same as in the mineral liskeardite. The spiral chains are joined together by octahedral edge-sharing to form layers parallel to (100). Synchrotron PXRD patterns collected at different temperatures during heating of the specimen show that the higher-hydrate mineral starts transforming to bulachite when heated to 50°C, and the transformation is complete between 75 and 100°C.


Author(s):  
Janice A. Frias ◽  
Brandon R. Goblirsch ◽  
Lawrence P. Wackett ◽  
Carrie M. Wilmot

OleC, a biosynthetic enzyme involved in microbial hydrocarbon biosynthesis, has been crystallized. Synchrotron X-ray diffraction data have been collected to 3.4 Å resolution. The crystals belonged to space groupP3121 orP3221, with unit-cell parametersa=b= 98.8,c= 141.0 Å.


2015 ◽  
Vol 71 (11) ◽  
pp. 1416-1420 ◽  
Author(s):  
Chen Pan ◽  
Yong-lin Hu ◽  
Xiang-ning Jiang ◽  
Ying Gai

CouR fromRhodopseudomonas palustrisis a member of the MarR transcriptional regulator family. It regulates the expression of CouA and CouB, enzymes that are involved in the degradation ofp-coumarate.In vivo, CouR binds to a DNA fragment containing thecouABpromoter and suppresses the expression of CouA and CouB, while binding ofp-coumaroyl-CoA attenuates its affinity towards DNA and activates the expression of CouA and CouB. Here, the crystallization and X-ray diffraction analyses of CouR alone and in complex withp-coumaroyl-CoA are reported. Apo and ligand-complexed CouR crystals diffracted to 2.5 and 3.3 Å resolution, respectively. The crystals of apo CouR belonged to space groupP22121, with unit-cell parametersa= 62.78,b = 76.15,c = 87.38 Å, whereas the crystals of the CouR–ligand complex belonged to space groupP212121, with unit-cell parametersa= 61.37,b= 69.82,c = 70.32 Å. The crystals were predicted to contain two CouR molecules or CouR–ligand complexes per asymmetric unit.


1994 ◽  
Vol 9 (3) ◽  
pp. 187-188 ◽  
Author(s):  
Hee-Lack Choi ◽  
Naoya Enomoto ◽  
Nobuo Ishizawa ◽  
Zenbe-e Nakagawa

X-ray powder diffraction data for Ti2O2(C2O4)(OH)2·H2O were obtained. The crystal system was determined to be orthorhombic with space group C2221. The unit cell parameters were refined to a = 1.0503(2) nm, b = 1.5509(3) nm, and c = 0.9700(1) nm.


Author(s):  
San Hadži ◽  
Abel Garcia-Pino ◽  
Kenn Gerdes ◽  
Jurij Lah ◽  
Remy Loris

The HigA2 antitoxin and the HigBA2 toxin–antitoxin complex fromVibrio choleraewere crystallized in complex with their operator box. Screening of 22 different DNA duplexes led to two crystal forms of HigA2 complexes and one crystal form of a HigBA2 complex. Crystals of HigA2 in complex with a 17 bp DNA duplex belong to space groupP3221, with unit-cell parametersa=b= 94.0,c= 123.7 Å, and diffract to 2.3 Å resolution. The second form corresponding to HigA2 in complex with a 19 bp duplex belong to space groupP43212 and only diffract to 3.45 Å resolution. Crystals of the HigBA2 toxin–antitoxin were obtained in complex with a 31 bp duplex and belonged to space groupP41212, with unit-cell parametersa=b= 113.6,c= 121.1 Å. They diffract to 3.3 Å resolution.


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