Tryptophan biosynthetic pathway in the Enterobacteriaceae: some physical properties of the enzymes

Abstract

Several physical properties of the first four enzymatic activities of the tryptophan pathway were examined using gel filtration and ion exchange chromatography. Five different patterns were noted. Differences in the anthranilate synthetase (AS) and phosphoribosylanthranilate transferase (PRT) defined these patterns. In all the organisms studied phosphoribosylanthranilate isomerase and indoleglycerol phosphate synthetase co-eluted from both diethylaminoethyl-cellulose and G-200 and thus probably are contained in a single polypeptide of 50,000 daltons. An AS-PRT complex was found in Citrobacter species, Enterobacter cloacae, and Erwinia dissolvens. In all the other bacteria examined AS and PRT were separate molecules. In Serratia marcescens, S. marinorubra, and Enterobacter liquefaciens, AS was 140,000 daltons and PRT was 45,000 daltons. In Erwinia carotavora and Enterobacter hafniae the AS was the same size as the Serratia species but the PRT was larger at 67,000 daltons. Two Proteus species had an AS and PRT of the same size as E. carotavora and E. hafniae but the Proteus AS was different in that it partially dissociated upon gel filtration. Aeramonas formicans was unique in its possession of an AS with a molecular weight of 220,000. The PRT of A. formicans was found to elute at 67,000 daltons. Possible paths of evolution of the tryptophan enzymes are discussed in terms of the reults of this study. The results presented here are also considered with respect to existing taxonomic schemes of the enteric bacteria. ucts of these genes, five different distribution patterns were found. These results were considered with respect to existing phylogenetic schemes and were used to clarify some of the natural relationships among the fungi. 239 on July 31, 2020 by guest

Dysregulation of serine biosynthesis contributes to the growth defect of a Mycobacterium tuberculosis crp mutant

“…Serine can be used for biosynthesis of glycine, cysteine and tryptophan in many organisms (Pizer, 1965;Ulane and Ogur, 1972;Largen and Belser, 1975;Kitabatake et al, 2000). In the present study, addition of glycine and cysteine, but not tryptophan, enhanced the growth of the crp mutants at levels similar to those observed with addition of serine.…”

Tryptophan biosynthesis in the marine luminous bacterium Vibrio harveyi

“…Largen and Belser (18) studied these two enzymes in 12 enteric bacterial species by using gel filtration and ion-exchange chromatography; five different patterns were observed. These authors found that the physical nature of the first two enzymes of the pathway correlates well with position in the usual taxonomic scheme for the enteric bacteria (18). The tryptophan enzymes of V. harveyi exhibit the gener#l characteristics of the enzymes of the Proteus and Erwinia species studied by Largen and Belser.…”

“…Characterization of the tryptophan biosynthetic enzymes has been useful in the classification and comparison of different bacteria. For example, in the so-called "type 1" enteric organisms (including E. coli, Salmonella typhimurium, Enterobacter aerogenes, and Erwinia dissolvens), AS and PRT activities are associated in a multimeric complex having a relatively high molecular weight (18). Not only are both components necessary for full AS function, but also (in E. coli and S. typhimurium at least) the association of AS and PRT in a complex causes the PRT activity to become sensitive to feedback inhibition by tryptophan.…”

Kinetic properties of Serratia marcescens adenosine 5'-diphosphate glucose pyrophosphorylase

“…Both enzymes were centrifuged at 30,000 x g for 10 min and redissolved in 0.05 M HEPES buffer, pH 7.0, containing 2 mM dithioerythritol and were dialyzed overnight against 100 volumes of the same buffer. Pyridoxal-phosphate activated the HY strain enzyme about 30%, whereas 3-phosphoglycerate activated the HY strain and S. liquefaciens enzymes 20 and 9%, respectively. None of the other metabolites tested stimulated activity.…”

“…In a study of other enzyme activities in the tryptophan biosynthetic pathway, it was observed that the anthanilate synthase (EC 4.1.3.27) and anthranilate phosphoribosyl transferase (EC 2.4.2.18) activities reside in a single large enzyme complex in E. coli, Salmonella sp., and E. aerogenes (7,20). In S. marcescens, S. marinorubra, and Enterobacter liquefaciens (now classified as Serratia liquefa- VOL.…”