scholarly journals Crystal Structure of the NAD Biosynthetic Enzyme Quinolinate Synthase

2005 ◽  
Vol 280 (29) ◽  
pp. 26645-26648 ◽  
Author(s):  
Haruhiko Sakuraba ◽  
Hideaki Tsuge ◽  
Kazunari Yoneda ◽  
Nobuhiko Katunuma ◽  
Toshihisa Ohshima
Keyword(s):  
Crystal Structure ◽  
Biosynthetic Enzyme ◽  
Quinolinate Synthase

scholarly journals 2P048 Crystal structure of the NAD biosynthetic enzyme quinolinate synthase

2005 ◽  
Vol 45 (supplement) ◽  
pp. S131
Author(s):  
H. Sakuraba ◽  
K. Yoneda ◽  
T. Ohshima ◽  
H. Tsuge ◽  
N. Katunuma
Keyword(s):  
Crystal Structure ◽  
Biosynthetic Enzyme ◽  
Quinolinate Synthase

Crystal structure of MqnD (TTHA1568), a menaquinone biosynthetic enzyme from Thermus thermophilus HB8

2009 ◽  
Vol 168 (3) ◽  
pp. 575-581 ◽  
Author(s):  
Ryoichi Arai ◽  
Kazutaka Murayama ◽  
Tomomi Uchikubo-Kamo ◽  
Madoka Nishimoto ◽  
Mitsutoshi Toyama ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Thermus Thermophilus ◽  
Biosynthetic Enzyme ◽  
Thermus Thermophilus Hb8

scholarly journals The Crystal Structure of the Novobiocin Biosynthetic Enzyme NovP: The First Representative Structure for the TylF O-Methyltransferase Superfamily

2010 ◽  
Vol 395 (2) ◽  
pp. 390-407 ◽  
Author(s):  
Inmaculada Gómez García ◽  
Clare E.M. Stevenson ◽  
Isabel Usón ◽  
Caren L. Freel Meyers ◽  
Christopher T. Walsh ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Biosynthetic Enzyme

scholarly journals Structure of the Bacillus anthracis dTDP-L-rhamnose-biosynthetic enzyme dTDP-4-dehydrorhamnose reductase (RfbD)

2017 ◽  
Vol 73 (12) ◽  
pp. 644-650
Author(s):  
Ashley Law ◽  
Alexander Stergioulis ◽  
Andrei S. Halavaty ◽  
George Minasov ◽  
Wayne F. Anderson ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Cell Wall ◽  
Bacillus Anthracis ◽  
Biosynthetic Pathway ◽  
Biosynthetic Enzyme ◽  
Cell Wall Polysaccharides ◽  
Positive Bacterium ◽  
Conserved Residues ◽  
Therapeutic Development ◽  
Deadly Disease

Bacillus anthracis is the causative agent of the deadly disease Anthrax. Its use in bioterrorism and its ability to re-emerge have brought renewed interest in this organism. B. anthracis is a Gram-positive bacterium that adds L-rhamnose to its cell-wall polysaccharides using the activated donor dTDP-β-L-rhamnose. The enzymes involved in the biosynthesis of the activated donor are absent in humans, which make them ideal targets for therapeutic development to combat pathogens. Here, the 2.65 Å resolution crystal structure of the fourth enzyme in the dTDP-β-L-rhamnose-biosynthetic pathway from B. anthracis, dTDP-4-dehydro-β-L-rhamnose reductase (RfbD), is presented in complex with NADP+. This enzyme catalyzes the reduction of dTDP-4-dehydro-β-L-rhamnose to dTDP-β-L-rhamnose. Although the protein was co-crystallized in the presence of Mg2+, the protein lacks the conserved residues that coordinate Mg2+.

A Rich Man, Poor Man Story ofS-Adenosylmethionine and Cobalamin Revisited

2018 ◽  
Vol 87 (1) ◽  
pp. 555-584 ◽  
Author(s):  
Jennifer Bridwell-Rabb ◽  
Tsehai A.J. Grell ◽  
Catherine L. Drennan
Keyword(s):  
Crystal Structure ◽  
Three Dimensional ◽  
Structural Data ◽  
Biosynthetic Enzyme ◽  
Structural Motifs ◽  
Compare And Contrast ◽  
Radical Enzymes

S-adenosylmethionine (AdoMet) has been referred to as both “a poor man's adenosylcobalamin (AdoCbl)” and “a rich man's AdoCbl,” but today, with the ever-increasing number of functions attributed to each cofactor, both appear equally rich and surprising. The recent characterization of an organometallic species in an AdoMet radical enzyme suggests that the line that differentiates them in nature will be constantly challenged. Here, we compare and contrast AdoMet and cobalamin (Cbl) and consider why Cbl-dependent AdoMet radical enzymes require two cofactors that are so similar in their reactivity. We further carry out structural comparisons employing the recently determined crystal structure of oxetanocin-A biosynthetic enzyme OxsB, the first three-dimensional structural data on a Cbl-dependent AdoMet radical enzyme. We find that the structural motifs responsible for housing the AdoMet radical machinery are largely conserved, whereas the motifs responsible for binding additional cofactors are much more varied.

scholarly journals The Crystal Structure of Fe4S4 Quinolinate Synthase Unravels an Enzymatic Dehydration Mechanism That Uses Tyrosine and a Hydrolase-Type Triad

2014 ◽  
Vol 136 (14) ◽  
pp. 5253-5256 ◽  
Author(s):  
Mickaël V. Cherrier ◽  
Alice Chan ◽  
Claudine Darnault ◽  
Debora Reichmann ◽  
Patricia Amara ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Dehydration Mechanism ◽  
Quinolinate Synthase

Crystal Structure Determination of Glycerol-Containing Lipids from Electron Diffraction Data. Use of Analog Compounds Based upon Configurational Isomers of Cyclopentane-1, 2, 3-TRIOL

1977 ◽  
Vol 35 ◽  
pp. 24-25
Author(s):  
Douglas L. Dorset ◽  
Anthony J. Hancock
Keyword(s):  
Crystal Structure ◽  
Electron Diffraction ◽  
Diffraction Data ◽  
Structure Determination ◽  
Crystal Surface ◽  
Coherent Scattering ◽  
Crystal Structure Determination ◽  
Electron Diffraction Data ◽  
Polar Group ◽  
Axis Orientation

Lipids containing long polymethylene chains were among the first compounds subjected to electron diffraction structure analysis. It was only recently realized, however, that various distortions of thin lipid microcrystal plates, e.g. bends, polar group and methyl end plane disorders, etc. (1-3), restrict coherent scattering to the methylene subcell alone, particularly if undistorted molecular layers have well-defined end planes. Thus, ab initio crystal structure determination on a given single uncharacterized natural lipid using electron diffraction data can only hope to identify the subcell packing and the chain axis orientation with respect to the crystal surface. In lipids based on glycerol, for example, conformations of long chains and polar groups about the C-C bonds of this moiety still would remain unknown.One possible means of surmounting this difficulty is to investigate structural analogs of the material of interest in conjunction with the natural compound itself. Suitable analogs to the glycerol lipids are compounds based on the three configurational isomers of cyclopentane-1,2,3-triol shown in Fig. 1, in which three rotameric forms of the natural glycerol derivatives are fixed by the ring structure (4-7).

Spherulitic crystal growth in the prodissoconch larval of Crassostrea virginica

1983 ◽  
Vol 41 ◽  
pp. 518-519
Author(s):  
George G. Cocks ◽  
Louis Leibovitz ◽  
DoSuk D. Lee
Keyword(s):  
Crystal Structure ◽  
Crassostrea Virginica ◽  
Crystal Orientation ◽  
Developmental Changes ◽  
Gastrula Stage ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Stages Of Growth ◽  
Early Stages ◽  
Initial Deposition

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.

Transmission Electron Microscopy studies of the vacancy ordering in YSI2-X thin films

1991 ◽  
Vol 49 ◽  
pp. 562-563
Author(s):  
F.-R. Chen ◽  
T. L. Lee ◽  
L. J. Chen
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Thin Films ◽  
Diffraction Pattern ◽  
Annealing Temperature ◽  
Lattice Mismatch ◽  
Si Substrate ◽  
Metal Thin Films ◽  
Transmission Electron ◽  
Vacancy Ordering

YSi2-x thin films were grown by depositing the yttrium metal thin films on (111)Si substrate followed by a rapid thermal annealing (RTA) at 450 to 1100°C. The x value of the YSi2-x films ranges from 0 to 0.3. The (0001) plane of the YSi2-x films have an ideal zero lattice mismatch relative to (111)Si surface lattice. The YSi2 has the hexagonal AlB2 crystal structure. The orientation relationship with Si was determined from the diffraction pattern shown in figure 1(a) to be and . The diffraction pattern in figure 1(a) was taken from a specimen annealed at 500°C for 15 second. As the annealing temperature was increased to 600°C, superlattice diffraction spots appear at position as seen in figure 1(b) which may be due to vacancy ordering in the YSi2-x films. The ordered vacancies in YSi2-x form a mesh in Si plane suggested by a LEED experiment.

Crystal Structure Analysis of Cu-Zr Alloys by Convergent Beam Diffraction

1981 ◽  
Vol 39 ◽  
pp. 354-355
Author(s):  
A. F. Marshall ◽  
J. W. Steeds ◽  
D. Bouchet ◽  
S. L. Shinde ◽  
R. G. Walmsley
Keyword(s):  
Crystal Structure ◽  
Point Group ◽  
Intermetallic Phase ◽  
Three Dimensional ◽  
Crystal Structure Analysis ◽  
Ion Milling ◽  
Composition And Structure ◽  
Unit Cells ◽  
Sputter Deposited ◽  
Convergent Beam

Convergent beam electron diffraction is a powerful technique for determining the crystal structure of a material in TEM. In this paper we have applied it to the study of the intermetallic phases in the Cu-rich end of the Cu-Zr system. These phases are highly ordered. Their composition and structure has been previously studied by microprobe and x-ray diffraction with sometimes conflicting results.The crystalline phases were obtained by annealing amorphous sputter-deposited Cu-Zr. Specimens were thinned for TEM by ion milling and observed in a Philips EM 400. Due to the large unit cells involved, a small convergence angle of diffraction was used; however, the three-dimensional lattice and symmetry information of convergent beam microdiffraction patterns is still present. The results are as follows:1) 21 at% Zr in Cu: annealed at 500°C for 5 hours. An intermetallic phase, Cu3.6Zr (21.7% Zr), space group P6/m has been proposed near this composition (2). The major phase of our annealed material was hexagonal with a point group determined as 6/m.

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