scholarly journals Crystallization and first data collection of the putative transfer protein TraN from the Gram-positive conjugative plasmid pIP501

Author(s):  
Nikolaus Goessweiner-Mohr ◽  
Christian Fercher ◽  
Mohammad Yaser Abajy ◽  
Elisabeth Grohmann ◽  
Walter Keller

Conjugative plasmid transfer is the most important route for the spread of resistance and virulence genes among bacteria. Consequently, bacteria carrying conjugative plasmids are a substantial threat to human health, especially hospitalized patients. Whilst detailed information about the process has been obtained for Gram-negative type-4 secretion systems, little is known about the corresponding mechanisms in Gram-positive (G+) bacteria. The successful purification and crystallization of the putative transfer protein TraN from the G+ conjugative model plasmid pIP501 ofEnterococcus faecalisare presented. Native crystals diffracted to 1.8 Å resolution on a synchrotron beamline. The crystals belonged to space groupP21, with unit-cell parametersa= 32.88,b = 54.94,c= 57.71 Å, β = 91.89° and two molecules per asymmetric unit.

1999 ◽  
Vol 55 (2) ◽  
pp. 522-524 ◽  
Author(s):  
Randall L. Oliver ◽  
Jacqueline M. Tremblay ◽  
George M. Helmkamp ◽  
Lynwood R. Yarbrough ◽  
Natalie W. Breakfield ◽  
...  

Phosphatidylinositol-transfer protein (PITP) is a soluble, ubiquitously expressed, highly conserved protein encoded by two genes in humans, rodents and other mammals. A cDNA encoding the alpha isoform of the rat gene was expressed to high levels in Escherichia coli, the protein purified and the homogeneous protein used for crystallization studies. Crystals of rat PITP-α were obtained by vapor-diffusion techniques using the sitting-drop method. Crystals grow within two weeks by vapor-diffusion techniques in the presence of polyethylene glycol 4000. Both crystal forms pack in the monoclinic space group P21. Crystal form I has unit-cell parameters a = 44.75, b = 74.25, c = 48.32 Å and β = 114.14°. Unit-cell parameters for crystal form II are a = 47.86, b = 73.59, c = 80.49 Å and β = 98.54°. Crystal form I has a Vm of 2.295 Å3 Da−1 and an estimated solvent content of 46.4% with one molecule per asymmetric unit, while crystal form II has a Vm of 2.196 Å3 Da−1 and an estimated solvent content of 44.0%, assuming two molecules per asymmetric unit.


2003 ◽  
Vol 67 (2) ◽  
pp. 277-301 ◽  
Author(s):  
Elisabeth Grohmann ◽  
Günther Muth ◽  
Manuel Espinosa

SUMMARY Conjugative transfer of bacterial plasmids is the most efficient way of horizontal gene spread, and it is therefore considered one of the major reasons for the increase in the number of bacteria exhibiting multiple-antibiotic resistance. Thus, conjugation and spread of antibiotic resistance represents a severe problem in antibiotic treatment, especially of immunosuppressed patients and in intensive care units. While conjugation in gram-negative bacteria has been studied in great detail over the last decades, the transfer mechanisms of antibiotic resistance plasmids in gram-positive bacteria remained obscure. In the last few years, the entire nucleotide sequences of several large conjugative plasmids from gram-positive bacteria have been determined. Sequence analyses and data bank comparisons of their putative transfer (tra) regions have revealed significant similarities to tra regions of plasmids from gram-negative bacteria with regard to the respective DNA relaxases and their targets, the origins of transfer (oriT), and putative nucleoside triphosphatases NTP-ases with homologies to type IV secretion systems. In contrast, a single gene encoding a septal DNA translocator protein is involved in plasmid transfer between micelle-forming streptomycetes. Based on these clues, we propose the existence of two fundamentally different plasmid-mediated conjugative mechanisms in gram-positive microorganisms, namely, the mechanism taking place in unicellular gram-positive bacteria, which is functionally similar to that in gram-negative bacteria, and a second type that occurs in multicellular gram-positive bacteria, which seems to be characterized by double-stranded DNA transfer.


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.


1999 ◽  
Vol 55 (8) ◽  
pp. 1459-1461 ◽  
Author(s):  
Núria Verdaguer ◽  
Thomas C. Marlovits ◽  
Jerónimo Bravo ◽  
David I. Stuart ◽  
Dieter Blaas ◽  
...  

Human rhinoviruses, the major cause of mild recurrent infections of the upper respiratory tract, are small icosahedral particles. Over 100 different serotypes have been identified. The majority (91 serotypes) use intercellular adhesion molecule 1 as the cell-attachment site; ten serotypes (the minor group) bind to members of the low-density lipoprotein receptor. Three different crystal forms of the minor-group human rhinovirus serotype 2 (HRV2) were obtained by the hanging-drop vapour-diffusion technique using ammonium sulfate and sodium/potassium phosphate as precipitants. Monoclinic crystals, space group P21, diffracted at least to 2.8 Å resolution, and two complete virus particles were located in the crystal asymmetric unit. A second type of crystals had a compact cubic like morphology and diffracted beyond 2.5 Å resolution. These crystals belong to a primitive orthorhombic space group, with unit-cell parameters a = 309.3, b = 353.5, c = 759.6 Å, and contain one virus particle in the asymmetric unit. A third type of crystals, with a prismatic shape and belonging to space group I222, was also obtained under similar crystallization conditions. These latter crystals, with unit-cell parameters a = 308.7, b = 352.2, c = 380.5 Å, diffracted to high resolution (beyond 1.8 Å) and contained 15 protomers per asymmetric unit; this requires that three perpendicular crystal twofold axes coincide with three of the viral particle's dyad axes.


Author(s):  
Sachin Wakadkar ◽  
Li-Qing Zhang ◽  
Duo-Chuan Li ◽  
Teemu Haikarainen ◽  
Prathusha Dhavala ◽  
...  

Cu,Zn superoxide dismutase (Cu,ZnSOD) from the thermophilic fungusChaetomium thermophilumwas expressed inPichia pastorisand purified. Crystals were grown in over 120 conditions but only those produced with 1.4 Msodium potassium phosphate pH 8.2 as precipitant were suitable for structural studies. Data were collected to 1.9 Å resolution at 100 K from a single crystal using a synchrotron-radiation source. The crystals belonged to space groupP61/P65, with unit-cell parametersa= 90.2,c= 314.5 Å and eight molecules in the asymmetric unit. Elucidation of the crystal structure will provide insights into the active site of the enzyme and a better understanding of the structure–activity relationship, assembly and thermal stability of Cu,ZnSODs.


Author(s):  
Seoung Min Bong ◽  
Seung Won Yang ◽  
Ji-Woong Choi ◽  
Seung Jun Kim ◽  
Byung Il Lee

Myotubularin-related protein 1 is a phosphatase that dephosphorylates phospholipids such as phosphatidylinositol 3-phosphate or phosphatidylinositol 3,5-bisphosphate. In this study, human MTMR1 was overexpressed inEscherichia coli, purified and crystallized at 277 K using polyethylene glycol 20 000 as a precipitant. Diffraction data were collected to 2.0 Å resolution using synchrotron radiation. The crystals belonged to space groupP1, with unit-cell parametersa= 67.219,b= 96.587,c= 97.581 Å, α = 87.597, β = 86.072, γ = 77.327°. Assuming the presence of four molecules in the asymmetric unit, the calculated Matthews coefficient value was 2.61 Å3 Da−1and the corresponding solvent content was 52.9%.


2014 ◽  
Vol 70 (10) ◽  
pp. 1424-1427 ◽  
Author(s):  
José A. Brito ◽  
André Gutierres ◽  
Kevin Denkmann ◽  
Christiane Dahl ◽  
Margarida Archer

The ability to perform the very simple oxidation of two molecules of thiosulfate to tetrathionate is widespread among prokaryotes. Despite the prevalent occurrence of tetrathionate formation and its well documented significance within the sulfur cycle, little is known about the enzymes that catalyze the oxidative condensation of two thiosulfate anions. To fill this gap, the thiosulfate dehydrogenase (TsdA) enzyme from the purple sulfur bacteriumAllochromatium vinosumwas recombinantly expressed inEscherichia coli, purified and crystallized, and a crystallographic data set was collected. The crystals belonged to the monoclinic space groupC2, with unit-cell parametersa= 79.2,b= 69.9,c= 57.9 Å, β = 129.3°, contained one monomer per asymmetric unit and diffracted to a resolution of 1.98 Å.


1999 ◽  
Vol 55 (9) ◽  
pp. 1616-1617
Author(s):  
I. Polikarpov ◽  
R. T. de Oliveira ◽  
J. Abrahão-Neto

L-Asparaginase is an enzyme which hydrolyzes asparagine to produce aspartic acid and ammonia. It is an effective chemotherapeutic drug, especially in the treatment of acute lymphoblastic leukaemia in children. The enzyme from Escherichia coli was crystallized in a new crystal form with space group C2, unit-cell parameters a = 76.3 (0), b = 134.6 (2), c = 64.8 (7) Å, β = 110.5 (1)° and a dimer in the asymmetric unit. Synchrotron-radiation diffraction data have been collected to 1.95 Å resolution.


Author(s):  
Shutao Xie

Uba5 is the smallest ubiquitin-like molecule-activating enzyme and contains an adenylation domain and a C-terminal region. This enzyme only exists in multicellular organisms. The mechanism through which the enzyme recognizes and activates ubiquitin-fold modifier 1 (Ufm1) remains unknown. In this study, Uba5 adenylation domains with different C-terminal region lengths were cloned, expressed and purified. The results of anin vitrotruncation assay suggest that Uba5 residues 57–363 comprise the minimal fragment required for the high-efficiency activation of Ufm1. Crystallization of Uba5 residues 57–363 was performed at 277 K using PEG 3350 as the precipitant, and crystals optimized by microseeding diffracted to 2.95 Å resolution, with unit-cell parametersa=b= 97.66,c= 144.83 Å, α = β = 90, γ = 120°. There is one molecule in the asymmetric unit; the Matthews coefficient and the solvent content were calculated to be 2.93 Å3 Da−1and 58.1%, respectively.


Sign in / Sign up

Export Citation Format

Share Document