The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)

Purification and characterization of trp aporepressor.

We have isolated homogeneous trp aporepressor from an overproducing strain of Escherichia coli carrying a plasmid containing trpR preceded by tandem trp operon promoters. Dye-affinity and ion-exchange chromatography were used in conjunction with a gel electrophoresis assay in which the repressor, when bound to the trp operator, protects an Rsa I restriction site from endonuclease cleavage. Crystals suitable for x-ray diffraction studies were grown from a variety of concentrated salt solutions. Hydrodynamic properties and electrophoretic analysis of unmodified and covalently crosslinked aporepressor show that the free aporepressor has an isoelectric point of 5.9 and is a dimer containing two identical 12.5-kilodalton subunits in the presence or absence of L-tryptophan. The repressor . operator complex binds poorly to nitrocellulose filters, but restriction-site protection studies indicate that, in the presence of tryptophan, one dimer is bound to the operator site with an apparent dissociation constant less than 2 X 10(-9) M. Preliminary equilibrium dialysis experiments suggest that tryptophan binds to the aporepressor with a dissociation constant of 1.6 X 10(-5) M.[1]


  1. Purification and characterization of trp aporepressor. Joachimiak, A., Kelley, R.L., Gunsalus, R.P., Yanofsky, C., Sigler, P.B. Proc. Natl. Acad. Sci. U.S.A. (1983) [Pubmed]
WikiGenes - Universities