Tryptic digestion of the A protein (a! subunit) of the tryptophan synthetase of Escherichia coli and separation of tryptic peptides by column and paper chromatography yielded 22 nonoverlapping peptides of the total of 25 anticipated on the basis of total amino acid composition of the A protein. The amino acid composition and sequence of each purified peptide were determined. These peptides acco...

Gartner, Theodore K. (University of California, Davis), and Monica Riley. Isolation of mutants affecting tryptophanase production in Escherichia coli. J. Bacteriol. 89:313-318. 1965.-Mutants of Escherichia coli K-12 were isolated which appear to have suffered an alteration in the regulation system governing tryptophanase synthesis. A novel selection method was used to isolate tryptophanase muta...

13C-NMR has been used to follow the tryptophan synthase (EC 4.2.1.20)-catalysed hydrogen-deuterium exchange of the pro-2R and pro-2S protons of [2-13C]glycine. The first- and second-order rate constants for exchange when the alpha 2 beta 2 enzyme complex is or is not saturated with glycine have been determined at pH 7.0 and 7.8. At pH 7.8 the effects of binding the allosteric effector, DL-alpha...

Sufficient evidence has accumulated in recent years, in part through gene enzyme studies in microorganisms (Bonner, 1951; Yanofsky, 1956), to implicate the gene as a regulator of certain qualitative and quantitative aspects of protein formation (Horowitz, 1956). Although examples of alterations in protein structure arising through gene mutation are limited in number, there are many cases in whi...

ion of the a-proton. The rate constant for the converkz sion of Intermediate 1 to Intermediate II with [a-Hlserine as Therefore, /L.~ = kZ = 3.17 s-1. substrate which we have obtained from stopped flow absorption For [a-Dlserine, kobs = 2.74 s-l = kz + kmz; kLJkz = 3. measurements (kobs = 6.3 s-l) is about 2 times higher than the Therefore, k-2 = 3 kt; k-z = 2.05 s-1; and kp = 0.685 s-1. rate c...

URING the past decade, a large number of td mutants have been isolated. These mutants represent alterations of the td locus, which controls the formation of tryptophan synthetase (TSase) in Neurospora crassa. Extensive biochemical and immunological studies have shown that these allelic mutants differ from each other in their ability to form protein (CRM, “crossreacting material”) serologically ...

Understanding protein tertiary and quaternary structures is crucial to a better understanding of their biological functions. Here we illustrate for tryptophan synthase that tandem mass spectrometry (MS/MS) reveals not only protein subunit architectures, but also protein unfolding behavior when coupled with ion mobility (IM). In the present study, we verified the subunit arrangement with surface...

The ability to acquire iron from the extracellular environment is a key determinant of pathogenicity in mycobacteria. Mycobacterium tuberculosis acquires iron exclusively via the siderophore mycobactin T, the biosynthesis of which depends on the production of salicylate from chorismate. Salicylate production in other bacteria is either a two-step process involving an isochorismate synthase (cho...