scholarly journals Ribokinase fromLeishmania donovani: purification, characterization and X-ray crystallographic analysis

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.

2014 ◽  
Vol 70 (12) ◽  
pp. 1675-1682 ◽  
Author(s):  
Roie Dann ◽  
Shifra Lansky ◽  
Noa Lavid ◽  
Arie Zehavi ◽  
Valery Belakhov ◽  
...  

Geobacillus stearothermophilusT6 is a thermophilic bacterium that possesses an extensive hemicellulolytic system, including over 40 specific genes that are dedicated to this purpose. For the utilization of xylan, the bacterium uses an extracellular xylanase which degrades xylan to decorated xylo-oligomers that are imported into the cell. These oligomers are hydrolyzed by side-chain-cleaving enzymes such as arabinofuranosidases, acetylesterases and a glucuronidase, and finally by an intracellular xylanase and a number of β-xylosidases. One of these β-xylosidases is Xyn52B2, a GH52 enzyme that has already proved to be useful for various glycosynthesis applications. In addition to its demonstrated glycosynthase properties, interest in the structural aspects of Xyn52B2 stems from its special glycoside hydrolase family, GH52, the structures and mechanisms of which are only starting to be resolved. Here, the cloning, overexpression, purification and crystallization of Xyn52B2 are reported. The most suitable crystal form that has been obtained belonged to the orthorhombicP212121space group, with average unit-cell parametersa = 97.7,b= 119.1,c = 242.3 Å. Several X-ray diffraction data sets have been collected from flash-cooled crystals of this form, including the wild-type enzyme (3.70 Å resolution), the E335G catalytic mutant (2.95 Å resolution), a potential mercury derivative (2.15 Å resolution) and a selenomethionine derivative (3.90 Å resolution). These data are currently being used for detailed three-dimensional structure determination of the Xyn52B2 protein.


Author(s):  
Marco Kloos ◽  
Antje Brüser ◽  
Jürgen Kirchberger ◽  
Torsten Schöneberg ◽  
Norbert Sträter

Whereas the three-dimensional structure and the structural basis of the allosteric regulation of prokaryotic 6-phosphofructokinases (Pfks) have been studied in great detail, knowledge of the molecular basis of the allosteric behaviour of the far more complex mammalian Pfks is still very limited. The human muscle isozyme was expressed heterologously in yeast cells and purified using a five-step purification protocol. Protein crystals suitable for diffraction experiments were obtained by the vapour-diffusion method. The crystals belonged to space groupP6222 and diffracted to 6.0 Å resolution. The 3.2 Å resolution structure of rabbit muscle Pfk (rmPfk) was placed into the asymmetric unit and optimized by rigid-body and groupB-factor refinement. Interestingly, the tetrameric enzyme dissociated into a dimer, similar to the situation observed in the structure of rmPfk.


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):  
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.


2014 ◽  
Vol 70 (9) ◽  
pp. 1206-1210 ◽  
Author(s):  
Chongyun Cheng ◽  
Jianhua Gu ◽  
Jing Su ◽  
Wei Ding ◽  
Jie Yin ◽  
...  

Fucokinase/L-fucose-1-P-guanylyltransferase (FKP) is a bifunctional enzyme which converts L-fucose to Fuc-1-P and thence to GDP-L-fucose through a salvage pathway. The molecular weights of full-length FKP (F-FKP) and C-terminally truncated FKP (C-FKP, residues 300–949) are 105.7 and 71.7 kDa, respectively. In this study, both recombinant F-FKP and C-FKP were expressed and purified. Size-exclusion chromatography experiments and analytical ultracentrifugation results showed that both F-FKP and C-FKP are trimers. Native F-FKP protein was crystallized by the vapour-diffusion method and the crystals belonged to space groupP212121and diffracted synchrotron X-rays to 3.7 Å resolution. The crystal unit-cell parameters area= 91.36,b= 172.03,c= 358.86 Å, α = β = γ = 90.00°. The three-dimensional features of the F-FKP molecule were observed by cryo-EM (cryo-electron microscopy). The preliminary cryo-EM experiments showed the F-FKP molecules as two parallel disc-shaped objects stacking together. Combining all results together, it is assumed that there are six FKP molecules in one asymmetric unit, which corresponds to a calculated Matthews coefficient of 2.19 Å3 Da−1with 43.83% solvent content. These preliminary crystallographic and cryo-EM microscopy analyses provide basic structural information on FKP.


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):  
Yury A. Kislitsyn ◽  
Valeriya R. Samygina ◽  
Igor A. Dvortsov ◽  
Nataliya A. Lunina ◽  
Inna P. Kuranova ◽  
...  

The crystallization and preliminary X-ray diffraction analysis of the carbohydrate-binding module (CBM) from laminarinase Lic16A of the hyperthermophilic anaerobic bacteriumClostridium thermocellum(ctCBM54) are reported. Recombinant ctCBM54 was prepared using anEscherichia coli/pQE30 overexpression system and was crystallized by the hanging-drop vapour-diffusion method. X-ray diffraction data were collected to 2.1 Å resolution using synchrotron radiation. The crystals belonged to space groupP6322, with unit-cell parametersa=b= 130.15,c= 131.05 Å. The three-dimensional structure of ctCBM54 will provide valuable information about the structure–function relation of the laminarinase Lic16A and will allow the exploitation of this binding module in biotechnological applications.


Author(s):  
Andrea Štěpánková ◽  
Jarmila Dušková ◽  
Tereza Skálová ◽  
Jindřich Hašek ◽  
Tomáš Koval' ◽  
...  

The bacterial enzyme organophosphorus acid anhydrolase (OPAA) is able to catalyze the hydrolysis of both proline dipeptides (Xaa-Pro) and several types of organophosphate (OP) compounds. The full three-dimensional structure of the manganese-dependent OPAA enzyme is presented for the first time. This enzyme, which was originally isolated from the marine bacteriumAlteromonas macleodii, was prepared recombinantly inEscherichia coli. The crystal structure was determined at 1.8 Å resolution in space groupC2, with unit-cell parametersa= 133.8,b= 49.2,c= 97.3 Å, β = 125.0°. The enzyme forms dimers and their existence in solution was confirmed by dynamic light scattering and size-exclusion chromatography. The enzyme shares the pita-bread fold of its C-terminal domain with related prolidases. The binuclear manganese centre is located in the active site within the pita-bread domain. Moreover, an Ni2+ion from purification was localized according to anomalous signal. This study presents the full structure of this enzyme with complete surroundings of the active site and provides a critical analysis of its relationship to prolidases.


Author(s):  
Saori Kamachi ◽  
Junya Nagao ◽  
Masahiro Miyashita ◽  
Yoshiaki Nakagawa ◽  
Hisashi Miyagawa ◽  
...  

A novel scorpion venom peptide, La1 fromLiocheles australasiae, with a molecular weight of 7.8 kDa, is presumed to possess a single von Willebrand factor type C (VWC) domain, a common protein module, based on the position of eight Cys residues in its sequence. The biological function of La1 is still unknown. Deciphering its three-dimensional structure will be helpful in understanding its biological function. La1 was crystallized by the sitting-drop vapour-diffusion method using magnesium sulfate as a precipitant. The crystals belonged to the monoclinic space groupC2, with unit-cell parametersa= 63.0,b= 30.2,c= 32.3 Å, β = 108.5°, and diffracted to 1.9 Å resolution. The calculatedVMbased on one molecule per asymmetric unit was 1.87 Å3 Da−1. The solvent content was 34.1%.


Author(s):  
V. P. Martini ◽  
A. Glogauer ◽  
J. Iulek ◽  
E. M. Souza ◽  
F. O. Pedrosa ◽  
...  

LipC12, a true lipase from family I.1 of bacterial lipases which was previously isolated through a metagenomics approach, contains 293 amino acids. Among lipases of known three-dimensional structure, it has a sequence identity of 47% to the lipase fromPseudomonas aeruginosaPAO1. Recombinant N-terminally His6-tagged LipC12 protein was expressed inEscherichia coli, purified in a homogenous form and crystallized in several conditions, with the best crystals being obtained using 2.0 Msodium formate and 0.1 Mbis-tris propane pH 7.0. X-ray diffraction data were collected to 2.70 Å resolution. The crystals belonged to the tetragonal space groupP4122, with unit-cell parametersa=b= 58.62,c = 192.60 Å.


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