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Citrate pH (citrate + ph)
Kinds of Citrate pH Selected AbstractsCrystallization and preliminary X-ray analysis of the glycogen synthase from Pyrococcus abyssiACTA CRYSTALLOGRAPHICA SECTION D, Issue 12 2003Cristina Horcajada Glycogen synthase catalyzes the transfer of glucosyl residues from ADP- or UDP-glucose to the non-reducing end of a growing ,-1,4-glucan chain. To date, no crystallographic structure of an animal/fungal glycogen synthase (family 3 of the glycosyl transferases) or a bacterial/plant glycogen/starch synthase (family 5) has been reported. This paper describes the recombinant expression, crystallization and preliminary X-ray analysis of the glycogen synthase from the hyperthermophilic archaeon Pyrococcus abyssi, the smallest enzyme of the members of families 3 and 5 of the glycosyl transferases. Crystals from this protein and from its selenomethionyl variant were grown in 100,mM sodium citrate pH 5.6 containing 20% PEG and 20% dioxane by the hanging-drop vapour-diffusion method at 293,K. The crystals, which grew as thin needles, diffracted to 3.5,Å resolution and belong to space group C2, with unit-cell parameters a = 202, b = 73, c = 149,Å, , = 131°. The crystallographic and biochemical data are consistent with either a dimer or a tetramer in the crystal asymmetric unit and a volume solvent content of 70 or 39%, respectively. [source] Crystallization and preliminary X-ray analysis of bucain, a novel toxin from the Malayan krait Bungarus candidusACTA CRYSTALLOGRAPHICA SECTION D, Issue 10-2 2002L. Watanabe Bucain is a three-finger toxin, structurally homologous to snake-venom muscarinic toxins, from the venom of the Malayan krait Bungarus candidus. These proteins have molecular masses of approximately 6000,8000,Da and encompass the potent curaremimetic neurotoxins which confer lethality to Elapidae and Hydrophidae venoms. Bucain was crystallized in two crystal forms by the hanging-drop vapour-diffusion technique in 0.1,M sodium citrate pH 5.6, 15% PEG 4000 and 0.15,M ammonium acetate. Form I crystals belong to the monoclinic system space group C2, with unit-cell parameters a = 93.73, b = 49.02, c = 74.09,Å, , = 111.32°, and diffract to a nominal resolution of 1.61,Å. Form II crystals also belong to the space group C2, with unit-cell parameters a = 165.04, b = 49.44, c = 127.60,Å, , = 125.55°, and diffract to a nominal resolution of 2.78,Å. The self-rotation function indicates the presence of four and eight molecules in the crystallographic asymmetric unit of the form I and form II crystals, respectively. Attempts to solve these structures by molecular-replacement methods have not been successful and a heavy-atom derivative search has been initiated. [source] Crystallization of the Mycobacterium tuberculosis cell-division protein FtsZACTA CRYSTALLOGRAPHICA SECTION D, Issue 12 2000Adelaine K. W. Leung Mycobacterium tuberculosis FtsZ (MtbFtsZ), an essential protein in bacterial cell division, has been crystallized in the presence of a new inhibitor of MtbFtsZ polymerization and GTPase activity, ethyl (6-amino-2,3-dihydro-4-phenyl-1H -pyrido[4,3- b][1,4]diazepin-8-yl)carbamate (SRI-7614). Crystals of the MtbFtsZ,SRI-7614 complex (form I, 30% polyethylene glycol 4000, 0.1,M sodium citrate pH 5.6, 0.2,M NH4OAc, 293,K) belong to space group P61 or P65, with unit-cell parameters a = 88.78, c = 178.02,Å, and diffract to 2.3,Å resolution. A second crystal form, of the GDP complex, grows in the presence or absence of Mg2+ from PEG 4000 at 277,K or from (NH4)2SO4 at 293,K, respectively (form II, space group P6222 or P6422, with unit-cell parameters a = 135.02, c = 328.97,Å or a = 129.30, c = 327.97,Å, respectively). Complete data sets to ,7,Å resolution have been collected from both. Exceptional form II crystals diffract to at least 4.5,Å resolution. Determination of the MtbFtsZ structure may advance the design of improved inhibitors of FtsZ polymerization. [source] Crystallization and preliminary X-ray analysis of the major peanut allergen Ara,h,1 core regionACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 9 2010Cerrone Cabanos Peanuts contain some of the most potent food allergens known to date. Ara,h,1 is one of the three major peanut allergens. As a first step towards three-dimensional structure elucidation, recombinant Ara,h,1 core region was cloned, expressed in Escherichia coli and purified to homogeneity. Crystals were obtained using 0.1,M sodium citrate pH 5.6, 0.1,M NaCl, 15% PEG 400 as precipitant. The crystals diffracted to 2.25,Å resolution using synchrotron radiation and belonged to the monoclinic space group C2, with unit-cell parameters a = 156.521, b = 88.991, c = 158.971,Å, , = 107.144°. Data were collected at the BL-38B1 station of SPring-8 (Hyogo, Japan). [source] The purification, crystallization and preliminary structural characterization of FAD-dependent monooxygenase PhzS, a phenazine-modifying enzyme from Pseudomonas aeruginosaACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 10 2006Neelakshi Gohain The blue chloroform-soluble bacterial metabolite pyocyanin (1-hydroxy-5-methyl-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,Å, , = , = 90, , = 110.5°. They contain two monomers of PhzS in the asymmetric unit and diffract to a resolution of 2.4,Å. Seleno- l -methionine-labelled PhzS also crystallizes in space group C2, but the unit-cell parameters change to a = 70.6, b = 76.2, c = 80.2,Å, , = , = 90, , = 110.5° and the diffraction limit is 2.7,Å. [source] The purification, crystallization and preliminary structural characterization of PhzM, a phenazine-modifying methyltransferase from Pseudomonas aeruginosaACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 9 2006Neelakshi 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-hydroxy-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,Å, , = 96.3, , = 106.6, , = 106.9°. They contain one dimer in the asymmetric unit and diffract to a resolution of 1.8,Å. Anomalous data to 2.3,Å resolution have been collected from seleno- l -methionine-labelled PhzM. [source] | ||||||||||