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Journal ArticleDOI

Phase annealing in SHELX-90: direct methods for larger structures

George M. Sheldrick
- 01 Jun 1990 - 
- Vol. 46, Iss: 6, pp 467-473
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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.

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Citations
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Mixed-Ligand Copper(II)-phenolate Complexes: Effect of Coligand on Enhanced DNA and Protein Binding, DNA Cleavage, and Anticancer Activity

TL;DR: The observed IC50 values reveal that complex 4, which effects conformational change on DNA and binds to BSA more strongly, exhibits a cytotoxicity higher than the other complexes, suggesting that 4 can be explored further as a potential anticancer drug.
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SIR2011: a new package for crystal structure determination and refinement

TL;DR: SIR2011, the successor of SIR2004, is the latest program of the SIR suite and can solve ab initio crystal structures of small- and medium-size molecules, as well as protein structures, using X-ray or electron diffraction data.
Journal ArticleDOI

Crystal structure of a mammalian phosphoinositide-specific phospholipase C delta.

TL;DR: The 2.4-Å structure of phospholipase Cδ1 reveals a multidomain protein incorporating modules shared by many signalling proteins that suggests a mechanism for membrane attachment and Ca2+ -dependent hydrolysis of second-messenger precursors.
Journal ArticleDOI

Silver(I)−Polynitrile Network Solids for Anion Exchange: Anion-Induced Transformation of Supramolecular Structure in the Crystalline State

TL;DR: In this article, the counteranion self-assembly of Ag(C14H20N6) has been used for the selfassembly of supramolecular solids whose topologies depend on the counter-anion.
Journal ArticleDOI

Self-Assembly of Tetra- and Hexanuclear Circular Helicates

TL;DR: The self-assembly of the tris-bipyridine ligands BI and BII with iron(II) salts yields polynuclear complexes displaying structures of cyclic double-helix type, termed circular helicates [n]cH (of order n).
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.