scholarly journals Overexpression, purification, crystallization and structure determination of AspB, a putative aspartate aminotransferase fromMycobacterium tuberculosis

Author(s):  
Deepak Chandra Saroj ◽  
Khundrakpam Herojit Singh ◽  
Avishek Anant ◽  
Bichitra K. Biswal

A recombinant version of a putative aspartate aminotransferase, AspB (encoded by the ORF Rv3565), fromMycobacterium tuberculosis(Mtb) was overexpressed inM. smegmatisand purified to homogeneity using liquid chromatography. Crystals of AspB were grown in a condition consisting of 0.2 Mammonium phosphate monobasic, 0.1 Mcalcium chloride dihydrate employing the hanging-drop vapour-diffusion method at 298 K. The crystals diffracted to a limit of 2.50 Å resolution and belonged to the orthorhombic space groupP212121, with unit-cell parametersa= 93.27,b= 98.19,c= 198.70 Å. The structure of AspB was solved by the molecular-replacement method using a putative aminotransferase fromSilicibacter pomeroyi(PDB entry 3h14) as the search model. The template shares 46% amino-acid sequence identity withMtbAspB. The crystal asymmetric unit contains four AspB molecules (theMrof each is 42 035 Da).

Author(s):  
Hyung Jin Cha ◽  
Jae-Hee Jeong ◽  
Yeon-Gil Kim

Penicillin-binding proteins (PBPs), which mediate the peptidoglycan biosynthetic pathway in the bacterial cell wall, have been intensively investigated as a target for the design of antibiotics. In this study, PBPD2, a low-molecular-weight PBP encoded bylmo2812fromListeria monocytogenes, was overexpressed inEscherichia coli, purified and crystallized at 295 K using the sitting-drop vapour-diffusion method. The crystal belonged to the primitive orthorhombic space groupP212121, with unit-cell parametersa= 37.7,b= 74.7,c= 75.1 Å, and diffracted to 1.55 Å resolution. There was one molecule in the asymmetric unit. The preliminary structure was determined by the molecular-replacement method.


Author(s):  
Muhammad Tayyab ◽  
Naeem Rashid ◽  
Clement Angkawidjaja ◽  
Shigenori Kanaya ◽  
Muhammad Akhtar

A thermoalkalophilic lipase (LIPSBS) from the newly isolatedGeobacillusstrain SBS-4S which hydrolyzes a wide range of fatty acids has been characterized. In the present study, the crystallization of purified LIPSBSusing the sitting-drop vapour-diffusion method and its X-ray diffraction studies are described. The crystals belonged to the orthorhombic space groupP212121, with unit-cell parametersa= 55.13,b= 71.75,c= 126.26 Å. The structure was determined at 1.6 Å resolution by the molecular-replacement method using the lipase fromG. stearothermophilusL1 as a model.


Author(s):  
Eun-Jung Kim ◽  
Kyung-Jin Kim

(S)-3-Hydroxybutyryl-CoA dehydrogenase fromClostridium butyricum(CbHBD) is an enzyme that catalyzes the second step in the biosynthesis ofn-butanol from acetyl-CoA by the reduction of acetoacetyl-CoA to 3-hydroxybutyryl-CoA. TheCbHBD protein was crystallized using the hanging-drop vapour-diffusion method in the presence of 2 Mammonium sulfate, 0.1 MCAPS pH 10.5, 0.2 Mlithium sulfate at 295 K. X-ray diffraction data were collected to a maximum resolution of 2.3 Å on a synchrotron beamline. The crystal belonged to space groupR3, with unit-cell parametersa=b= 148.5,c= 201.6 Å. With four molecules per asymmetric unit, the crystal volume per unit protein weight (VM) is 3.52 Å3 Da−1, which corresponds to a solvent content of approximately 65.04%. The structure was solved by the molecular-replacement method and refinement of the structure is in progress.


2014 ◽  
Vol 70 (11) ◽  
pp. 1566-1569
Author(s):  
Eun-Jung Kim ◽  
Kyung-Jin Kim

Polyhydroxybutyrate (PHB) is a biopolymer that is in the spotlight because of its broad applications in bioplastics, fine chemicals, implant biomaterials and biofuels. PhaA fromRalstonia eutropha(RePhaA) is the first enzyme in the PHB biosynthetic pathway and catalyzes the condensation reaction of two acetyl-CoA molecules to give acetoacetyl-CoA.RePhaA was crystallized using the hanging-drop vapour-diffusion method in the presence of 20% polyethylene glycol monomethyl ether 2K, 0.1 MTris–HCl pH 8.5 and 0.2 MtrimethylamineN-oxide dihydrate at 295 K. X-ray diffraction data were collected to a maximum resolution of 1.96 Å on a synchrotron beamline. The crystal belonged to space groupP21, with unit-cell parametersa= 68.38,b= 105.47,c= 106.91 Å, α = γ = 90, β = 106.18°. With four subunits per asymmetric unit, the crystal volume per unit protein weight (VM) is 2.3 Å3 Da−1, which corresponds to a solvent content of approximately 46.2%. The structure was solved by the molecular-replacement method and refinement of the structure is in progress.


1999 ◽  
Vol 55 (11) ◽  
pp. 1920-1922 ◽  
Author(s):  
K. N. Rao ◽  
S. S. Hegde ◽  
R. J. Lewis ◽  
C. G. Suresh

A Bowman–Birk type trypsin/chymotrypsin inhibitor isolated from Vigna unguiculata seeds has been crystallized. Crystals were grown using the vapour-diffusion method at pH 4.0 using citrate/phosphate as a buffer and 30% saturated ammonium sulfate as precipitant. The crystals belonged to the monoclinic space group P21, with unit-cell parameters a = 32.4, b = 61.8, c = 32.9 Å, β = 114.5°. The Matthews coefficient calculated assuming two molecules in the asymmetric unit was 1.95 Å3 Da−1, which corresponds to a 37% solvent content. X-ray data were collected to 2.5 Å resolution from a flash-frozen crystal. The structure was solved using the molecular-replacement method using tracy soybean inhibitor structure (PDB entry 1pi2) as a model.


Author(s):  
Dongmin Yu ◽  
Xiaofang Chen ◽  
Zhongdong Xu ◽  
Honghua Ge

Dephospho-CoA kinases (DPCKs) are members of the kinase family that catalyze the final step in CoA biosynthesis. Their function is phosphorylation of the 3-hydroxyl group of the ribose using ATP as a phosphate donor. Structural changes induced by ATP binding play an important role during the DPCK catalytic cycle. In this work, DPCK fromLegionella pneumophilawas overexpressed inEscherichia coli. The purification, crystallization and preliminary X-ray analysis of crystals of this protein are described. The protein was crystallized in space groupP21212, with unit-cell parametersa= 36.29,b= 82.20,c= 81.80 Å, using the hanging-drop vapour-diffusion method. Diffraction data were collected at 100 K and the phases were determined using the molecular-replacement method.


2014 ◽  
Vol 70 (9) ◽  
pp. 1244-1248 ◽  
Author(s):  
Hackwon Do ◽  
Il-Sup Kim ◽  
Young-Saeng Kim ◽  
Sun-Young Shin ◽  
Jin-Ju Kim ◽  
...  

Monodehydroascorbate reductase (MDHAR; EC 1.6.5.4) is a key enzyme in the reactive oxygen species (ROS) detoxification system of plants. The participation of MDHAR in ascorbate (AsA) recycling in the ascorbate–glutathione cycle is important in the acquired tolerance of crop plants to abiotic environmental stresses. Thus, MDHAR represents a strategic target protein for the improvement of crop yields. Although physiological studies have intensively characterized MDHAR, a structure-based functional analysis is not available. Here, a cytosolic MDHAR (OsMDHAR) derived fromOryza sativaL.japonicawas expressed usingEscherichia colistrain NiCo21 (DE3) and purified. The purified OsMDHAR showed specific enzyme activity (approximately 380 U per milligram of protein) and was crystallized using the hanging-drop vapour-diffusion method at pH 8.0 and 298 K. The crystal diffracted to 1.9 Å resolution and contained one molecule in the asymmetric unit (the Matthews coefficientVMis 1.98 Å3 Da−1, corresponding to a solvent content of 38.06%) in space groupP41212 with unit-cell parametersa=b= 81.89,c= 120.4 Å. The phase of the OsMDHAR structure was resolved by the molecular-replacement method using a ferredoxin reductase fromAcidovoraxsp. strain KKS102 (PDB entry 4h4q) as a model.


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.


1999 ◽  
Vol 55 (11) ◽  
pp. 1952-1954 ◽  
Author(s):  
Franck Coste ◽  
Nadège Hervouet ◽  
Jacques Oberto ◽  
Charles Zelwer ◽  
Bertrand Castaing

The homodimeric form α2 of the Escherichia coli DNA-binding protein HU was crystallized by the hanging-drop vapour-diffusion method using PEG 4000 as a precipitant. The crystals belong to space group I222, with unit-cell parameters a = 31.09, b = 55.34, c = 117.63 Å, and contain one monomer per asymmetric unit. A full diffraction data set was collected to 2.3 Å resolution on a conventional X-ray source. The molecular-replacement method, using the HU crystallographic model from Bacillus stearothermophilus as a starting point, gave a reliable solution for the rotation and translation functions.


Author(s):  
Ruyi Ding ◽  
Cui Xu ◽  
Xu Chen ◽  
Mengyun Bao ◽  
Xiaoting Qiu

The 2-carboxy-6-hydroxyoctahydroindole moiety is an essential residue for the antithrombotic activity of aeruginosins, which are a class of cyanobacteria-derived bioactive linear tetrapeptides. The biosynthetic pathway of the 2-carboxy-6-hydroxyoctahydroindole moiety has not yet been resolved. AerF was indicated to be involved in the biosynthesis of the 2-carboxy-6-hydroxyoctahydroindole moiety. This study reports the cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of AerF fromMicrocystis aeruginosawith a C-terminal His6tag. The crystal diffracted to a maximum resolution of 1.38 Å and belonged to the tetragonal space groupP4322, with unit-cell parametersa=b= 101.581,c= 116.094 Å. The calculated Matthews coefficient and solvent content of the crystal were 2.47 Å3 Da−1and 50.32%, respectively. The initial model of the structure was obtained by the molecular-replacement method and refinement of the structure is in progress.


Sign in / Sign up

Export Citation Format

Share Document