Tryptophan super-repressors with alanine 77 changes.
نویسندگان
چکیده
منابع مشابه
Intragenic complementation between Escherichia coli trp repressors with different defects in the tryptophan-binding pocket.
Site-directed mutagenesis of the trpR gene (encoding the trp repressor, TrpR) was used to replace Gly85 with tryptophan (Trp or W), in order to place Trp near its normal location in the L-tryptophan(L-W)-binding pocket. The resulting mutant protein (G85W) exhibits weak, but significant repressor activity in vivo that is independent of the presence of L-W in the media. This mutant negatively com...
متن کاملProduction of a novel tryptophan analog, beta-1-indazole-L-alanine with tryptophan synthase of Escherichia coli.
The tryptophan synthase alpha 2 beta 2 complex from Escherichia coli has been found to catalyze the beta-replacement reaction of L-serine with indazole, an indole analog which has a nitrogen atom at the 2-position (pyrazole ring). The reaction product was isolated and identified as beta-indazolealanine by mass spectrometric, elemental and NMR analyses. Careful assignment of 1H- and 13C-signals ...
متن کاملRepressors
Jacques Monod and Francois Jacob, our heroes, described a gene-regulatory world run exclusively by repressors. The activities of repressors, their abilities to bind DNA as we later learned, would be controlled — helped or hindered — by small molecules that bind these proteins. They showed [1] that networks of considerable complexity could be created with such a regulatory system. There was no n...
متن کاملRegulated by the Tryptophan and Tyrosine Repressors in Escherichia coli K-12t
The regulation of transcription of the gene for the tryptophan-specffic permease, mtr, was evaluated in several genetically marked Escherichia coli strains through the use of a single-copy lacZ reporter system. The expression of mtr was repressed 97-fold by tryptophan via the Trp repressor and induced 10-fold by phenylalanine or tyrosine via the Tyr repressor. By primer extension analysis two d...
متن کاملTryptophan catabolism by tryptophan pyrrolase in rat liver. The effect of tryptophan loads and changes in tryptophan pyrrolase activity.
We investigated how changes in tryptophan pyrrolase activity and tryptophan loads affect the breakdown of tryptophan was estimated by injecting rats with [ring-2-14-C]tryptophan and measuring respiratory 14-CO2. We concluded, contrary to previous reports, that induction of tryptophan pyrrolase definitely will increase the rate of tryptophan breakdown. Tryptophan loads also increase tryptophan b...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1993
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(18)53618-8