Journal ArticleDOI
Phase annealing in SHELX-90: direct methods for larger structures
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TLDR
In this article, a phase annealing method, related to the simulated-annealing approach in other optimization problems, is proposed and it is shown that it can result in an improvement of up to an order of magnitude in the chances of solving large structures at atomic resolution.Abstract:
A number of extensions to the multisolution approach to the crystallographic phase problem are discussed in which the negative quartet relations play an important role. A phase annealing method, related to the simulated annealing approach in other optimization problems, is proposed and it is shown that it can result in an improvement of up to an order of magnitude in the chances of solving large structures at atomic resolution. The ideas presented here are incorporated in the program system SHELX-90; the philosophical and mathematical background to the direct-methods part (SHELXS) of this system is described.read more
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A bacterial collagen-binding domain with novel calcium-binding motif controls domain orientation
TL;DR: Investigation of the crystal structure of a collagen‐binding domain with an N‐terminal domain linker from Clostridium histolyticum class I collagenase reveals a β‐sheet sandwich fold with the linker adopting an α‐helix, which is confirmed by changes in the Stokes and hydrodynamic radii and by dynamic light scattering with and without calcium.
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Three coordinate divalent Group 14 element compounds with a β-diketiminate as supporting ligand L2MX [L2=PhNC(Me)CHC(Me)NPh, X=Cl, I; M=Ge, Sn]
TL;DR: In this article, the halide ligand of all compounds can either be removed by reaction with NaBPh4 leading to the cationic Ge(II) and Sn (II) species L2M+ or may be replaced by other groups after nucleophilic substitution giving L2MR compounds [R=N(SiMe3)2; M=Ge, Sn. M=Sn; R=OSO2CF3, N3].
Journal ArticleDOI
Synthesis of (1S,3aS)-8-(2,3,3a,4,5, 6-hexahydro-1H-phenalen-1-yl)-1-phenyl-1,3,8-triaza-spiro[4. 5]decan-4-one, a potent and selective orphanin FQ (OFQ) receptor agonist with anxiolytic-like properties.
Jürgen Wichmann,Geo Adam,Stephan Röver,Michael Hennig,Michelangelo Scalone,Cesura Andrea,Frank M. Dautzenberg,Francois Jenck +7 more
TL;DR: In vivo following intraperitoneal injection, compound 3c was found to decrease neophobia in a novel environment and to exhibit dose-dependent anxiolytic-like effects in the elevated plus-maze procedure, thus confirming the effects observed following intracerebroventricular infusion of the OFQ peptide in rat.
Journal ArticleDOI
The crystal structures of Zea mays and Arabidopsis 4-hydroxyphenylpyruvate dioxygenase.
TL;DR: The first x-ray structures of the plant HPPDs of Zea mays and Arabidopsis in their substrate-free form are reported, providing direct evidence that the C-terminal helix gates substrate access to the active site around a nonheme ferrous iron center.
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From Dicarboxylic Acid to Tetranuclear Metallamacrocyclic Complex and 1D and 2D Polymers
TL;DR: A series of metal carboxylate complexes have been synthesized by treating 2,6-dicarboxamido-(2-pyridyl)-pyridine (H2dcapp), pyridine-2,5-H2pda, and phenanthroline (phen) wi...
References
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Book
Crystallographic Computing 3: Data Collection, Structure Determination, Proteins and Databases
TL;DR: The latest in a series on crystallographic computing, this collection of 33 papers covers the full spectrum of computer applications in crystallography, including the use of micro-, mini-, and mainframe computers.