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Z Dauter

Publications and source records attributed to Z Dauter.

At least 127 records · Page 7Linked to original sources
PubMed1992

Crystallization of recombinant chitobiase from Serratia marcescens.

We are currently investigating the biochemical and structural properties of both chitin degrading enzymes chitinase and chitobiase from Serratia marcescens. Previously we have reported the first crystallization and characterization of chitinase crystals (Vorgias et al., 1992). In this communication we present the first crystallization of chitobiase. The protein was synthesized in Escherichia coli and purified to homogeneity using cation exchange chromatography and fast protein liquid chromatography. The crystals have the shape of small prisms and the space group is P2(1) with beta = 101.0 degrees and unit cell dimensions a = 63.2 A, b = 133.2 A, c = 55.1 A. They diffract X-rays to about 2.5 A resolution and are suitable for three-dimensional structural analysis.

Acetylglucosaminidase↗
PubMed1992

Three-dimensional structure of catalase from Micrococcus lysodeikticus at 1.5 A resolution.

The three-dimensional crystal structure of catalase from Micrococcus lysodeikticus has been solved by multiple isomorphous replacement and refined at 1.5 A resolution. The subunit of the tetrameric molecule of 222 symmetry consists of a single polypeptide chain of about 500 amino acid residues and one haem group. The crystals belong to space group P4(2)2(1)2 with unit cell parameters a = b = 106.7 A, c = 106.3 A, and there is one subunit of the tetramer per asymmetric unit. The amino acid sequence has been tentatively determined by computer graphics model building and comparison with the known three-dimensional structure of beef liver catalase and sequences of several other catalases. The atomic model has been refined by Hendrickson and Konnert's least-squares minimisation against 94,315 reflections between 8 A and 1.5 A. The final model consists of 3,977 non-hydrogen atoms of the protein and haem group, 426 water molecules and one sulphate ion. The secondary and tertiary structures of the bacterial catalase have been analyzed and a comparison with the structure of beef liver catalase has been made.

Amino Acid Sequence↗
PubMed1992

Crystallization and preliminary X-ray analysis of the complex between a mouse Fab fragment and a single IgG-binding domain from streptococcal protein G.

The Fab fragment of a mouse immunoglobulin G1, complexed with a single IgG-binding domain from streptococcal protein G, has been crystallized in a form suitable for analysis by X-ray diffraction. The needle-shaped crystals were grown from polyethylene glycol 4000 using vapour diffusion methods and diffract to 2.3 A resolution. The space group is P2(1)2(1)2(1) (a = 64.5 A, b = 70.5 A and c = 120.1 A), with one Fab-protein G domain complex in the asymmetric unit. Solution of the three-dimensional structure of the complex will permit a detailed analysis of the molecular interactions between protein G and the Fab portion of IgG.

Animals↗
PubMed1992

High-resolution X-ray structures of pig metmyoglobin and two CD3 mutants: Mb(Lys45----Arg) and Mb(Lys45----Ser).

The structure of pig aquometmyoglobin has been refined to a crystallographic R-factor of 19.8% against X-ray diffraction data between 10- and 1.75-A spacing. The final structural model comprises two molecules of pig myoglobin, 233 water molecules, and two sulfate ions. A water molecule is coordinated to each of the heme iron atoms with an average Fe-OH2 bond distance of 2.19 A, and the mean Fe-N epsilon (proximal histidine-93) distance is 2.20 A. In contrast to the structure of sperm whale metmyoglobin, the iron is not significantly displaced from the plane of the heme. At the entrance to the heme pocket, the side-chain amino group of lysine-45 (CD3) is well-defined in the electron density map and forms salt-bridging interactions with the heme 6-propionate and with a sulfate ion. Serine and arginine replacements have been made previously at position 45 to examine the proposal that the CD3 side chain acts as a barrier to ligand entry into the protein. Crystal structures of the arginine-45 and serine-45 mutant metmyoglobins have been solved to 1.9 and 2.0 A resolution, respectively. In both cases the structural changes are confined to the site of mutation. Arginine-45 takes up a conformation closely similar to that observed for this residue in wild-type sperm whale myoglobin, in which it makes more extensive charge-charge and charge-dipole interactions and appears to restrict the movement of the distal histidine away from the ligand. The hydroxyl group of serine-45 is disordered, but it is clear that the effect of the mutation is to open up the solvent-exposed face of the heme pocket.

Animals↗
PubMed1992

Crystallization and preliminary crystallographic studies of glucosamine-6-phosphate deaminase from Escherichia coli K12.

Hexameric glucosamine-6-phosphate deaminase from Escherichia coli has been crystallized isomorphously with both phosphate and ammonium sulphate as precipitants, over a wide pH range (6.0 to 9.0). The crystals belong to space group R32 and the cell parameters in the hexagonal setting are a = b = 125.9 A and c = 223.2 A. A complete native data set was collected to 2.1 A resolution. Self-rotation function studies suggest that the hexamers sit on the 3-fold axis and have point group symmetry 32, with a non-crystallographic dyad relating two monomers linked by an interchain disulfide bridge. A possible packing for the unit cell is proposed.

Aldose-Ketose Isomerases↗
PubMed1992

Crystallization of recombinant chitinase from the cloned chiA gene of Serratia marcescens.

The chiA gene encoding for the chitinase enzyme from Serratia marcescens was efficiently overexpressed under the pL promoter and the enzyme was secreted into the growth medium. The chitinase was purified to homogeneity using affinity chromatography on a Phenyl-Sepharose column and the protein was successfully crystallized. The crystals are presently in the form of small needles in space group C222(1) and have unit cell dimensions a = 204(+/- 0.5) A, b = 134(+/- 0.5) A, c = 60(+/- 0.5) A. The crystals diffract X-rays to about 3 A resolution and are suitable for three-dimensional structural analysis.

Chitinases↗
PubMed1992

A TIM barrel protein without enzymatic activity? Crystal-structure of narbonin at 1.8 A resolution.

The major protein component in seeds is storage protein. These have no known enzymatic activity and act to provide amino acids as a source of metabolites in the developing seedling. We report here the first three dimensional crystal structure of a seed storage globulin at high resolution. The molecule of the 2S globulin, narbonin, from Vicia narbonensis L., consists of an eight-stranded parallel alpha/beta barrel structure similar to that observed in triose phosphate isomerase (TIM). Narbonin is the first protein with this topology possessing no known enzymatic activity. Because of the lack of sequence information most of the primary structure was determined directly from the electron density.

Amino Acid Sequence↗
PubMed1992

Initiating a crystallographic study of a class II fructose-1,6-bisphosphate aldolase.

We have reproducibly crystallized the metal-dependent Class II fructose-1,6-bisphosphate aldolase from Escherichia coli. Crystals in the shape of truncated hexagonal bipyramids have unit cell dimensions of a = b = 78.4 A, c = 290.6 A and are suitable for a detailed structural analysis. The space group has been identified as P6(1)22 or enantiomorph. Data sets to approximately 2.9 A resolution have been recorded using both the Rigaku R-AXIS IIc image plate area detector coupled to a copper target rotating anode X-ray source and using the MAR image plate systems with synchrotron radiation at the EMBL outstation DESY in Hamburg, and at S.R.S. Daresbury. Diffraction beyond 2.5 A has been observed when large freshly grown crystals are used with the synchrotron beam. A data set to this resolution has been collected. Several putative heavy-atom derivative data sets have also been measured using synchrotron radiation facilities and analysis of these data sets is in progress.

Crystallization↗
PubMed1992

The polypeptide chain fold in tyrosine phenol-lyase, a pyridoxal-5'-phosphate-dependent enzyme.

The tyrosine phenol lyase (EC 4.1.99.2) from Citrobacter intermedius has been crystallised in the apo form by vapour diffusion. The space group is P2(1)2(1)2. The unit cell has dimensions a = 76.0 A, b = 138.3 A, c = 93.5 A and it contains two subunits of the tetrameric molecule in the asymmetric unit. Diffraction data for the native enzyme and two heavy atom derivatives have been collected with synchrotron radiation and an image plate scanner. The structure has been solved at 2.7 A resolution by isomorphous replacement with subsequent modification of the phases by averaging the density around the non-crystallographic symmetry axis. The electron density maps clearly show the relative orientation of the subunits and most of the trace of the polypeptide chain. Each subunit consists of two domains. The topology of the large domain appears to be similar to that of the aminotransferases.

Chemical Phenomena↗
PubMed1992

Crystal structure of a dUTPase.

The enzyme dUTPase catalyses the hydrolysis of dUTP and maintains a low intracellular concentration of dUTP so that uracil cannot be incorporated into DNA. dUTPase from Escherichia coli is strictly specific for its dUTP substrate, the active site discriminating between nucleotides with respect to the sugar moiety as well as the pyrimidine base. Here we report the three-dimensional structure of E. coli dUTPase determined by X-ray crystallography at a resolution of 1.9 A. The enzyme is a symmetrical trimer, and of the 152 amino acid residues in the subunit, the first 136 are visible in the crystal structure. The tertiary structure resembles a jelly-roll fold and does not show the 'classical' nucleotide-binding domain. In the quaternary structure there is a complex interaction between the subunits that may be important in catalysis. This possibility is supported by the location of conserved elements in the sequence.

Amino Acid Sequence↗
PubMed1992

Refinement of rubredoxin from Desulfovibrio vulgaris at 1.0 A with and without restraints.

X-ray data have been recorded from crystals of rubredoxin derived from the bacterium Desulfovibrio vulgaris to a resolution of 1.0 A using in part synchrotron radiation and in part X-rays from a sealed-tube Mo K alpha source. In both cases an imaging-plate scanner was used as detector. The space group of the crystals is P2(1) with cell dimensions a = 19.97, b = 41.45, c = 24.41 A and beta = 108.3 degrees. The overall merging R(I) factor between symmetry-related reflections was 5.8%. The model was refined by least-squares minimization initially with stereochemical restraints to an R factor of 16.4%. Only atomic positional parameters and isotropic temperature factors for non-H atoms were used in the refinement. There were 18,532 independent X-ray observations for a total of 1916 atomic parameters. A round of unrestrained refinement gave an R factor of 16.0%, acceptable geometry for more than 90% of the protein atoms, but emphasized the disorder inherent in eight of the residues. A final round of restrained refinement gave an R factor of 14.7%. Three of the 389 protein atoms in the molecule, in the side chain of Lys2, have been assigned zero occupancy in the model. A total of eight atoms in three side chains have been assigned two conformations, giving 393 protein atomic sites in the model. In addition there is one Fe atom, a sulfate ion and 102 water sites. 339 H atoms were included at their calculated positions, which were not refined. There is clear evidence for anisotropic thermal motion. This has not been incorporated in the present model.

Crystallization↗
PubMed1991

Complex between the subtilisin from a mesophilic bacterium and the leech inhibitor eglin-C.

The alkaline proteinase from the mesophilic bacterium Bacillus mesentericus has been crystallized in a 1:1 complex with the inhibitor eglin-C from the medical leech. The crystals have cell dimensions of a = 43.0, b = 71.9, c = 48.3 A and beta = 110.0 degrees and are in the space group P2(1). Three-dimensional data to 2.0 A have been recorded on film from a single crystal. The orientation and position of the complex in the unit cell have been established using the refined coordinates of subtilisin Carlsberg and of eglin-C as independent models. The structure of the complex has been refined by restrained least-squares minimization. The crystallographic R factor (= sigma[magnitude of Fo - magnitude of Fc[/sigma magnitude of Fo) is 15.1% including two Ca2+ ions and 312 water molecules. The structure is discussed in terms of its physicochemical properties in solution and its relation to other Bacillus subtilisins.

Amino Acid Sequence↗
PubMed1991

Cloning, overexpression, purification and crystallisation of ribosomal protein L9 from Bacillus stearothermophilus.

The cloning, sequencing and overexpression of the gene coding for Bacillus stearothermophilus ribosomal protein L9 is described. The sequence corresponds directly to that presented for the protein itself by classical methods, differing at only a few amino acid positions. The purification and crystallisation of the corresponding L9 protein is presented. The crystals are isomorphous to those described for L9 obtained by conventional methods.

Amino Acid Sequence↗
PubMed1991

X-ray structure of an unusual Ca2+ site and the roles of Zn2+ and Ca2+ in the assembly, stability, and storage of the insulin hexamer.

Metal ion binding to the insulin hexamer has been investigated by crystallographic analysis. Cadmium, lead, and metal-free hexamers have been refined to R values of 0.181, 0.172, and 0.172, against data of 1.9-, 2.5-, and 2.5-A resolution, respectively. These structures have been compared with each other and with the isomorphous two-zinc insulin. The structure of the metal-free hexamer shows that the His(B10) imidazole rings are arranged in a preformed site that binds a water molecule and is poised for Zn2+ coordination. The structure of the cadmium derivative shows that the binding of Cd2+ at the center of the hexamer is unusual. There are three symmetry-related sites located within 2.7 A of each other, and this position is evidently one-third occupied. It is also shown that the coordinating B13 glutamate side chains of this derivative have two partially occupied conformations. One of these conformations is two-thirds occupied and is very similar to that seen in two-zinc insulin. The other, one-third-occupied conformation, is seen to coordinate the one-third-occupied metal ion. The binding of Ca2+ to insulin is assumed to be essentially identical with that of Cd2+. Thus, we conclude that the Ca2+ binding site in the insulin hexamer is unlike that of any other known calcium binding protein. The crystal structures reported herein explain how binding of metal ions stabilizes the insulin hexamer. The role of metal ions in hexamer assembly and dissociation is discussed.

Animals↗
PubMed1990

Purification and crystallization of 15-lipoxygenase from rabbit reticulocytes.

We report a new purification of rabbit reticulocyte 15-lipoxygenase that has resulted in the first crystallization of a mammalian lipoxygenase. The enzyme was purified to homogeneity (greater than 98% pure by SDS-PAGE) using high pressure liquid chromatography on hydrophobic-interaction, hydroxyapatite and cation-exchange columns. Crystals were grown by the vapor diffusion method from concentrated solutions of the protein in sodium phosphate buffer, pH 7.0. The hexagonal, rod-shaped crystals were on average 0.09 mm x 0.09 mm x 0.4 mm, with approximate unit cell dimensions of a = b = 260 A, c = 145 A. The crystals diffract to 5 A resolution.

Animals↗
PubMed1990

Refinement of glucose isomerase from Streptomyces albus at 1.65 A with data from an imaging plate.

The structure of 'metal-free' glucose isomerase of Streptomyces albus strain number YT ATCC 21132 has been analysed and refined at 1.65 A. The space group is I222, with cell dimensions a = 93.9 (1), b = 99.7 (1) and c = 102.9 (1) A, and there is one monomer of the tetrameric molecule per asymmetric unit. The data were recorded from two crystals of the protein using synchrotron radiation from the EMBL beamline X11 at DESY, Hamburg. Data were recorded with an imaging plate scanner designed and built in the EMBL Hamburg outstation. The total data-collection time was less than 12 h and the processing of all data took less than 2 days. The coordinates of the Arthrobacter glucose isomerase refined at a resolution of 2.5 A were used as a starting model. The structure of the protein and of 445 associated water molecules in the asymmetric unit were refined by restrained least-squares minimization using all data between 8 and 1.65 A to a final R factor of 14.1%.

Aldose-Ketose Isomerases↗
PubMed1990

Preliminary crystallographic analysis of the breakage-reunion domain of the Escherichia coli DNA gyrase A protein.

The 64 x 10(3) Mr N-terminal breakage-reunion domain of the Escherichia coli DNA gyrase A protein was purified from an over-expressing strain. When complexed with the gyrase B protein, this truncated A protein has all of the enzymic properties of the full-length counterpart, although with reduced efficiency in some cases. The 64 x 10(3) Mr protein has been crystallized in several forms, a number of which were too small for crystallographic analysis. However, two forms grew to sufficient size for preliminary X-ray analysis. Both forms were tetragonal with a primitive lattice. One form (type I) had cell dimensions of a = b = 170 A, c = 145 A a space group of either P41212 (P43212) or P42212, and diffracted to 6 A resolution. The type II crystals had cell dimensions of a = b = 177 A, c = 175 A, a space group of P41212 (P43212) or P42212, and diffracted to at least 4.5 A resolution. Both crystal forms apparently contained four subunits (possibly a tetramer) in the asymmetric unit. We are attempting to increase the size and quality of these crystals.

DNA Topoisomerases, Type II↗