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Journal ArticleDOI

Specific binding of leucyl transfer rna to an immature form of l-threonine deaminase: its implications in repression

01 Aug 1970-Proceedings of the National Academy of Sciences of the United States of America (National Academy of Sciences)-Vol. 66, Iss: 4, pp 1027-1035
TL;DR: The in vitro assembly of L-threonine deaminase from its constituent parts results in the formation of an inactive species of this enzyme which specifically and reversibly binds leucyl-tRNA.
Abstract: The in vitro assembly of L-threonine deaminase from its constituent parts results in the formation of an inactive species of this enzyme which specifically and reversibly binds leucyl-tRNA. The native, catalytically active enzyme, which is derived from this species in the presence of maturation-inducing ligands, does not bind tRNA. The possible involvement of this protein-tRNA complex in the repression of the ilv (ADE) operon is discussed.
Citations
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Journal ArticleDOI
TL;DR: Presentation de la sixieme carte genetique de Salmonella typhimurium comprenant 532 genes, plus de quelques nouvelles methodes et de nouveaux materiels pour l'analyse genetiques.

650 citations

Journal ArticleDOI
01 Mar 1974-Science
TL;DR: Autogenous regulation provides the cell with means for accomplishing a number of different regulatory tasks, each suited to better satisfying the needs of the organism for its survival.
Abstract: A new term, autogenous regulation, is used to describe a phenomenon that is not a new discovery but rather is newly appreciated as a mechanism common to a number of systems in both prokaryotic and eukaryotic organisms. In this mechanism the product of a structural gene regulates expression of the operon in which that structural gene resides. In many (perhaps all) cases, the regulatory gene product has several functions, since it may act not only as a regulatory protein but also as an enzyme, structural protein, or antibody, for example. In a few cases, this protein is the multimeric allosteric enzyme that catalyzes the first step of a metabolic pathway, gearing together the two most important mechanisms for controlling the biosynthesis of metabolites in bacterial cells—feedback inhibition and repression. Autogenous regulation may provide a mechanism for amplification of gene expression (84); for severe and prolonged inactivation of gene expression (85); for buffering the response of structural genes to changes in the environment (45, 52); and for maintaining a constant intracellular concentration of a protein, independent of cell size or growth rate (86). Thus, autogenous regulation provides the cell with means for accomplishing a number of different regulatory tasks, each suited to better satisfying the needs of the organism for its survival.

183 citations

Journal ArticleDOI
TL;DR: The coordinate system used in this edition is neither minutes of transfer time in conjugation crosses nor units representing "phage lengths" of DNA of the transducing phage P22, as used in earlier editions, but centisomes and kilobases based on physical analysis of the lengths of DNA segments between genes.

163 citations

Journal ArticleDOI
TL;DR: A procedure has been devised for the purification of the biosynthetic l-threonine deaminase from a genetically derepressed mutant, strain TIR8, of Escherichia coli K-12, which produces a purifying of 400-fold relative to derepression enzyme levels and 4000-foldrelative to repressed levels.

82 citations