Relative activities and stabilities of mutant Escherichia coli tryptophan synthase alpha subunits
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چکیده
منابع مشابه
Solubilization and renaturation of overexpressed aggregates of mutant tryptophan synthase alpha-subunits.
Certain Escherichia coli tryptophan synthase mutant alpha-subunits encoded from mutagenized trpA-containing plasmids were overexpressed as insoluble aggregates which were seen as large, intracellular inclusion bodies. The insoluble aggregates were solubilized to various degrees by several neutral, chaotropic salts. The order of effectiveness of these salts (KSCN, NaI greater than NaNO3, LiBr gr...
متن کاملInteractions of tryptophan synthetase subunits in Escherichia coli containing mutationally altered beta2 subunits.
The (Y and /I2 subunits of tryptophan synthetase are specified by the A and B genes, respectively, of the trp operon in Escherichia coli. Missense mutations in trpB result in catalytically inactive /I2 subunits. In some cases, these mutations also diminish the catalytic and /I2 subunit stimulating activities of the (Y subunit in cell extracts. Analysis of repressor-negative (trpR) strains havin...
متن کاملRestoration of enzymic activity by complementation in vitro between mutant alpha subunits of tryptophan synthetase and between mutant subunits and fragments of the alpha subunit.
The wild type and all mutant OL chains of tryptophan synthetase tested can, following denaturation-renaturation, enter into stable dimeric structures. Only certain combinations of mutant a! chains yield diiers which have the enzymatic activity which the mutant monomers lack. Most OL chains with mutational alterations in the NH2-terminal half of the molecule will complement most a! chains that a...
متن کاملImmunochemical and enzymatic comparisons of the tryptophan synthase alpha subunits from five species of Enterobacteriaceae.
The reactive surface structures of alpha subunits of tryptophan synthase from Escherichia coli, Shigella dysenteriae, Salmonella typhimurium, Aerobacter aerogenes, and Serratia marcescens were compared by measuring (i) their reactivities in micro-complement-fixation assays with antibodies directed specifically to E. coli wild-type alpha subunit, (ii) their reactivities in enzyme neutralization ...
متن کاملStudy of cysteine residues in the alpha subunit of Escherichia coli tryptophan synthase. 1. Role in conformational stability.
To eludicate the role in conformational stability of Cys residues buried in the interior of a protein, the thermodynamic properties of denaturation of mutant alpha subunit of Escherichia coli tryptophan synthase, in which Ser, Ala, Val or Gly was substituted for each of the three Cys residues, were analyzed using calorimetry. The mutants were less stable than the wild type, indicating that Cys ...
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ژورنال
عنوان ژورنال: Journal of Bacteriology
سال: 1991
ISSN: 0021-9193,1098-5530
DOI: 10.1128/jb.173.6.1886-1893.1991