scholarly journals PsEst3, a new psychrophilic esterase from the Arctic bacterium Paenibacillus sp. R4: crystallization and X-ray crystallographic analysis

Author(s):  
Hyun Kim ◽  
Ae Kyung Park ◽  
Jun Hyuck Lee ◽  
Seung Chul Shin ◽  
Hyun Park ◽  
...  

Esterases are very useful biocatalysts in industry: they hydrolyze esters and split them into a carboxylic acid and an alcohol. The psychrophilic esterase PsEst3 was obtained from Paenibacillus sp. R4, which was isolated from the active layer of the permafrost in Council, Alaska. PsEst3 was successfully overexpressed using a psychrophilic chaperonin co-expression system and was purified by nickel-affinity and size-exclusion chromatography. Recombinant PsEst3 was crystallized at 290 K using the hanging-drop vapour-diffusion method. X-ray diffraction data were collected to 2.1 Å resolution. The crystal was determined to belong to space group P4132 or P4332, with unit-cell parameters a = b = c = 145.33 Å. Further crystallographic analysis needs to be conducted to investigate the structure and function of this esterase.

2015 ◽  
Vol 71 (11) ◽  
pp. 1396-1400 ◽  
Author(s):  
Sze Lei Pang ◽  
Kok Lian Ho ◽  
Jitka Waterman ◽  
Aik-Hong Teh ◽  
Fook Tim Chew ◽  
...  

Dermatophagoides farinaeis one of the major house dust mite (HDM) species that cause allergic diseases. N-terminally His-tagged recombinant Der f 21 (rDer f 21), a group 21 allergen, with the signal peptide truncated was successfully overexpressed in anEscherichia coliexpression system. The purified rDer f 21 protein was initially crystallized using the sitting-drop vapour-diffusion method. Well diffracting protein crystals were obtained after optimization of the crystallization conditions using the hanging-drop vapour-diffusion method with a reservoir solution consisting of 0.19 MTris–HCl pH 8.0, 32% PEG 400 at 293 K. X-ray diffraction data were collected to 1.49 Å resolution using an in-house X-ray source. The crystal belonged to theC-centered monoclinic space groupC2, with unit-cell parametersa= 123.46,b= 27.71,c= 90.25 Å, β = 125.84°. The calculated Matthews coefficient (VM) of 2.06 Å3 Da−1suggests that there are two molecules per asymmetric unit, with a solvent content of 40.3%. Despite sharing high sequence identity with Blo t 5 (45%) and Blo t 21 (41%), both of which were determined to be monomeric in solution, size-exclusion chromatography, static light scattering and self-rotation function analysis indicate that rDer f 21 is likely to be a dimeric protein.


Author(s):  
Thien-Hoang Ho ◽  
Myoung-Ki Hong ◽  
Ho-Phuong-Thuy Ngo ◽  
Lin-Woo Kang

RNA polymerase (RNAP) plays a crucial role in gene expression in all organisms. It is a multiprotein complex that produces primary transcript RNA. Generally, the basal transcription apparatus in archaea is simpler than the eukaryotic RNA polymerase II counterpart. To understand the structure and function of archaeal RNAP, theTON-0309gene encoding DNA-directed RNA polymerase subunit L (ToRNAP_L) fromThermococcus onnurineusNA1 was cloned and the protein was overexpressed inEscherichia coli, purified and crystallized. The purified protein was crystallized using the hanging-drop vapour-diffusion method and the crystal diffracted to 2.10 Å resolution. The crystal belonged to the hexagonal space groupP6122, with unit-cell parametersa=b= 42.3,c= 211.2 Å. One molecule was present in the asymmetric unit, with a correspondingVMof 2.5 Å3 Da−1and a solvent content of 50.0%.


Author(s):  
Asaithambi Killivalavan ◽  
Ningning Zhuang ◽  
Young Shik Park ◽  
Kon Ho Lee

A UDP-glucose:tetrahydrobiopterin α-glucosyltransferase (BGluT) enzyme was discovered in the cyanobacteriumSynechococcussp. PCC 7942 which transfers a glucose moiety from UDP-glucose to tetrahydrobiopterin (BH4). BGluT protein was overexpressed with selenomethionine labelling for structure determination by the multi-wavelength anomalous dispersion method. The BGluT protein was purified by nickel-affinity and size-exclusion chromatography. It was then crystallized by the hanging-drop vapour-diffusion method using a well solution consisting of 0.1 Mbis-tris pH 5.5, 19%(w/v) polyethylene glycol 3350 with 4%(w/v) D(+)-galactose as an additive. X-ray diffraction data were collected to 1.99 Å resolution using a synchrotron-radiation source. The crystals belonged to the monoclinic space groupC2, with unit-cell parametersa= 171.35,b= 77.99,c = 53.77 Å, β = 90.27°.


2014 ◽  
Vol 70 (9) ◽  
pp. 1256-1259
Author(s):  
Mohan Zhao ◽  
Li Wang ◽  
Heng Zhang ◽  
Yuhui Dong ◽  
Yong Gong ◽  
...  

RsmI and RsmH are AdoMet-dependent methyltransferases that are responsible for the 2′-O-methylation andN4-methylation of C1402 ofEscherichia coli16S rRNA, respectively. Modification of this site has been found to play a role in fine-tuning the shape and function of the P-site to increase the decoding fidelity. It is interesting to study the mechanism by which C1402 can be methylated by both RsmI and RsmH. The crystal structure of RsmH in complex with AdoMet and cytidine has recently been determined and provided some implications forN4-methylation of this site. Here, the purification and crystallization of RsmI as well as its preliminary crystallographic analysis are reported. Co-crystallization of RsmI with AdoMet was carried out by the sitting-drop vapour-diffusion method and X-ray diffraction data were collected to 2.60 Å resolution on beamline 1W2B at BSRF. The crystal contained three molecules per asymmetric unit and belonged to space groupC2, with unit-cell parametersa= 121.9,b= 152.5,c= 54.2 Å, β = 93.4°.


Author(s):  
Chinar Pathak ◽  
Sun-Bok Jang ◽  
Hookang Im ◽  
Hye-Jin Yoon ◽  
Bong-Jin Lee

SAV0479, a hypothetical protein from the Mu50 strain of methicillin- and vancomycin-resistantStaphylococcus aureus, was selected for structure and function determination as part of a structural genomics project. Here, the cloning, overexpression, purification and crystallization of SAV0479 are reported. Crystals were obtained by the hanging-drop vapour-diffusion method and diffraction data were collected to a resolution of 2.8 Å. The crystals belonged to space groupP3121, with unit-cell parametersa=b= 81.48,c= 82.53 Å. Three monomers of SAV0479 are present in each asymmetric unit.


Author(s):  
Xiao Zhang ◽  
Xi-Mei Xue ◽  
Yu Yan ◽  
Jun Ye

ArsH is an NADPH-dependent flavin mononucleotide reductase and is frequently encoded as part of anarsoperon. The function of thearsHgene remains to be characterized. Crystallization and structural studies may contribute to elucidating the specific biological function of ArsH associated with arsenic resistance. ArsH fromSynechocystissp. strain PCC 6803 was overproduced, purified and crystallized. Crystals were obtained by the sitting-drop vapour-diffusion method. Diffraction data were collected and processed to a resolution of 1.6 Å. The crystals belonged to the tetragonal space groupI4122, with unit-cell parametersa=b= 127.94,c= 65.86 Å and one molecule in the asymmetric unit. Size-exclusion chromatography and molecular-replacement results showed that the ArsH formed a tetramer. Further structural analysis and comparison with ArsH fromSinorhizobium melilotiwill provide information about the oligomerization of ArsH.


2014 ◽  
Vol 70 (10) ◽  
pp. 1362-1367 ◽  
Author(s):  
Emmanuel Nji ◽  
Dianfan Li ◽  
Declan A. Doyle ◽  
Martin Caffrey

The prokaryotic lysine-specific permease (LysP) belongs to the amino acid–polyamine–organocation (APC) transporter superfamily. In the cell, members of this family are responsible for the uptake and recycling of nutrients, for the maintenance of a constant internal ion concentration and for cell volume regulation. The detailed mechanism of substrate selectivity and transport of L-lysine by LysP is not understood. A high-resolution crystal structure would enormously facilitate such an understanding. To this end, LysP fromPseudomonas aeruginosawas recombinantly expressed inEscherichia coliand purified to near homogeneity by immobilized metal ion-affinity chromatography (IMAC) and size-exclusion chromatography (SEC). Hexagonal- and rod-shaped crystals were obtained in the presence of L-lysine and the L-lysine analogue L-4-thialysine by vapour diffusion and diffracted to 7.5 Å resolution. The diffraction data were indexed in space groupP21, with unit-cell parametersa= 169.53,b= 169.53,c= 290.13 Å, γ = 120°.


Author(s):  
Anneli Wennman ◽  
Ernst H. Oliw ◽  
Saeid Karkehabadi

Lipoxygenases constitute a family of nonhaem metal enzymes with catalytic iron or, occasionally, catalytic manganese. Lipoxygenases oxidize polyunsaturated fatty acids with position specificity and stereospecificity to hydroperoxides, which contribute to inflammation and the development of cancer. Little is known about the structural differences between lipoxygenases with Fe or Mn and the metal-selection mechanism. APichia pastorisexpression system was used for the production of the manganese lipoxygenase of the take-all fungus of wheat,Gaeumannomyces graminis. The active enzyme was treated with α-mannosidase, purified to apparent homogeneity and subjected to crystal screening and X-ray diffraction. The crystals diffracted to 2.6 Å resolution and belonged to space groupC2, with unit-cell parametersa= 226.6,b= 50.6,c= 177.92 Å, β = 91.70°.


Author(s):  
Santhosh Gatreddi ◽  
Sayanna Are ◽  
Insaf Ahmed Qureshi

Leishmaniais an auxotrophic protozoan parasite which acquires D-ribose by transporting it from the host cell and also by the hydrolysis of nucleosides. The enzyme ribokinase (RK) catalyzes the first step of ribose metabolism by phosphorylating D-ribose using ATP to produce D-ribose-5-phosphate. To understand its structure and function, the gene encoding RK fromL. donovaniwas cloned, expressed and purified using affinity and size-exclusion chromatography. Circular-dichroism spectroscopy of the purified protein showed comparatively more α-helix in the secondary-structure content, and thermal unfolding revealed theTmto be 317.2 K. Kinetic parameters were obtained by functional characterization ofL. donovaniRK, and theKmvalues for ribose and ATP were found to be 296 ± 36 and 116 ± 9.0 µM, respectively. Crystals obtained by the hanging-drop vapour-diffusion method diffracted to 1.95 Å resolution and belonged to the hexagonal space groupP61, with unit-cell parametersa=b= 100.25,c= 126.77 Å. Analysis of the crystal content indicated the presence of two protomers in the asymmetric unit, with a Matthews coefficient (VM) of 2.45 Å3 Da−1and 49.8% solvent content. Further study revealed that human counterpart of this protein could be used as a template to determine the first three-dimensional structure of the RK from trypanosomatid parasites.


2015 ◽  
Vol 71 (9) ◽  
pp. 1156-1160 ◽  
Author(s):  
Tong Huo ◽  
Xiang Liu

Nonstructural protein 15 (nsp15), also called endoribonuclease, is a gene product of open reading frame 1b (ORF 1b) in coronaviruses. It is an important enzyme in the transcription/replication process involved in discontinuous negative-strand RNA synthesis. In this work, mutants of nsp15 fromHuman coronavirus 229E(HCoV-229E) were made based on structural analysis of the homologous nsp15s inSevere acute respiratory syndrome coronavirus(SARS-CoV) andMouse hepatitis virus(MHV). The I26A/N52A mutant of nsp15 was overexpressed, purified and crystallized, and this mutant led to a trimeric form rather than hexamers or monomers. Crystals of trimeric nsp15 were obtained by the hanging-drop vapour-diffusion method using polyethylene glycol as a precipitant and diffracted to 2.5 Å resolution. The crystals belonged to space groupC2221, with unit-cell parametersa= 85.9,b= 137.5,c= 423.1 Å, α = β = γ = 90°.


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