Preliminary Structural Characterization (preliminary + structural_characterization)

Distribution by Scientific Domains


Selected Abstracts


Preliminary structural characterization of human SOUL, a haem-binding protein

ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 7 2009
Filipe Freire
Human SOUL (hSOUL) is a 23,kDa haem-binding protein that was first identified as the PP23 protein isolated from human full-term placentas. Here, the overexpression, purification and crystallization of hSOUL are reported. The crystals belonged to space group P6422, with unit-cell parameters a = b = 145, c = 60,┼ and one protein molecule in the asymmetric unit. X-ray diffraction data were collected to 3.5,┼ resolution at the ESRF. A preliminary model of the three-dimensional structure of hSOUL was obtained by molecular replacement using the structures of murine p22HBP (PDB codes 2gov and 2hva), obtained by solution NMR, as search models. [source]


Native and nonnative conformational preferences in the urea-unfolded state of barstar

PROTEIN SCIENCE, Issue 12 2004
Neel S. Bhavesh
NMR, nuclear magnetic resonance; HSQC, hetero-nuclear single-quantum coherence Abstract The refolding of barstar from its urea-unfolded state has been studied extensively using various spectroscopic probes and real-time NMR, which provide global and residue-specific information, respectively, about the folding process. Here, a preliminary structural characterization by NMR of barstar in 8 M urea has been carried out at pH 6.5 and 25░C. Complete backbone resonance assignments of the urea-unfolded protein were obtained using the recently developed three-dimensional NMR techniques of HNN and HN(C)N. The conformational propensities of the polypeptide backbone in the presence of 8 M urea have been estimated by examining deviations of secondary chemical shifts from random coil values. For some residues that belong to helices in native barstar, 13C, and 13CO secondary shifts show positive deviations in the urea-unfolded state, indicating that these residues have propensities toward helical conformations. These residues are, however, juxtaposed by residues that display negative deviations indicative of propensities toward extended conformations. Thus, segments that are helical in native barstar are unlikely to preferentially populate the helical conformation in the unfolded state. Similarly, residues belonging to ,-strands 1 and 2 of native barstar do not appear to show any conformational preferences in the unfolded state. On the other hand, residues belonging to the ,-strand 3 segment show weak nonnative helical conformational preferences in the unfolded state, indicating that this segment may possess a weak preference for populating a helical conformation in the unfolded state. [source]


Crystallization and preliminary structural characterization of the two actin-depolymerization factors of the malaria parasite

ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 5 2010
Jani Huttu
The malaria parasite Plasmodium depends on its actin-based motor system for motility and host-cell invasion. Actin-depolymerization factors are important regulatory proteins that affect the rate of actin turnover. Plasmodium has two actin-depolymerization factors which seem to have different functions and display low sequence homology to the higher eukaryotic family members. Plasmodium actin-depolymerization factors 1 and 2 have been crystallized. The crystals diffracted X-rays to maximum resolutions of 2.0 and 2.1,┼ and belonged to space groups P3121 or P3221, with unit-cell parameters a = b = 68.8, c = 76.0,┼, and P21212, with unit-cell parameters a = 111.6, b = 57.9, c = 40.5,┼, respectively, indicating the presence of one or two molecules per asymmetric unit in both cases. [source]


The purification, crystallization and preliminary structural characterization of FAD-dependent monooxygenase PhzS, a phenazine-modifying enzyme from Pseudomonas aeruginosa

ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 10 2006
Neelakshi Gohain
The blue chloroform-soluble bacterial metabolite pyocyanin (1-hydroxy-5-şmethyl-phenazine) contributes to the survival and virulence of Pseudomonas aeruginosa, an important Gram-negative opportunistic pathogen of humans and animals. Little is known about the two enzymes, designated PhzM and PhzS, that function in the synthesis of pyocyanin from phenazine-1-carboxylic acid. In this study, the FAD-dependent monooxygenase PhzS was purified and crystallized from lithium sulfate/ammonium sulfate/sodium citrate pH 5.5. Native crystals belong to space group C2, with unit-cell parameters a = 144.2, b = 96.2, c = 71.7,┼, , = , = 90, , = 110.5░. They contain two monomers of PhzS in the asymmetric unit and diffract to a resolution of 2.4,┼. Seleno- l -şmethionine-labelled PhzS also crystallizes in space group C2, but the unit-cell parameters change to a = 70.6, b = 76.2, c = 80.2,┼, , = , = 90, , = 110.5░ and the diffraction limit is 2.7,┼. [source]


The purification, crystallization and preliminary structural characterization of PhzM, a phenazine-modifying methyltransferase from Pseudomonas aeruginosa

ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 9 2006
Neelakshi Gohain
Pyocyanin, phenazine-1-carboxylic acid and more than 70 related compounds collectively known as phenazines are produced by various species of Pseudomonas, including the fluorescent pseudomonad P. aeruginosa, a Gram-negative opportunistic pathogen in humans and animals. P. aeruginosa synthesizes a characteristic blue water-soluble compound called pyocyanin (1-şhydroxy-5-methyl-phenazine). Two enzymes designated PhzM and PhzS are involved in the terminal steps of its synthesis and very little is known about these enzymes. In this study, PhzM, a dimeric S -adenosylmethionine-dependent methyltransferase, was purified and crystallized from PEG 3350/sodium cacodylate/sodium citrate pH 6.5. The crystals belong to space group P1, with unit-cell parameters a = 46.1, b = 61.8, c = 69.6,┼, , = 96.3, , = 106.6, , = 106.9░. They contain one dimer in the asymmetric unit and diffract to a resolution of 1.8,┼. Anomalous data to 2.3,┼ resolution have been collected from seleno- l -şmethionine-labelled PhzM. [source]