Metabolism of d -Arabinose: a New Pathway in Escherichia coli

Abstract

Several growth characteristics of Escherichia coli K-12 suggest that growth on l -fucose results in the synthesis of all the enzymes necessary for growth on d -arabinose. Conversely, when a mutant of E. coli is grown on d -arabinose, all of the enzymes necessary for immediate growth on l -fucose are present. Three enzymes of the l -fucose pathway in E. coli , l -fucose isomerase, l -fuculokinase, and l -fuculose-l-phospháte aldolase possess activity on d -arabinose, d -ribulose, and d -ribulose-l-phosphate, respectively. The products of the aldolase, with d -ribulose-l-phosphate as substrate, are dihydroxyacetone phosphate and glycolaldehyde. l -Fucose, but not d -arabinose, is capable of inducing these activities in wild-type E. coli . In mutants capable of utilizing d -arabinose as sole source of carbon and energy, these activities are induced in the presence of d -arabinose and in the presence of l -fucose. Mutants unable to utilize l -fucose, selected from strains capable of growth on d -arabinose, are found to have lost the ability to grow on d -arabinose. Enzymatic analysis of cell-free extracts, prepared from cultures of these mutants, reveals that a deficiency in any of the l -fucose pathway enzymes results in the loss of ability to utilize d -arabinose. Thus, the pathway of d -arabinose catabolism in E. coli K-12 is believed to be: d -arabinose ⇌ d -ribulose → d -ribulose-l-phosphate ⇌ dihydroxyacetone phosphate plus glycolaldehyde. Evidence is presented which suggests that the glycolaldehyde is further oxidized to glycolate.

Aldehyde dehydrogenase induction by glutamate in Escherichia coli

“…In this metabolic pathway, the enzyme oxidizes glycolaldehyde to glycolate. The formation of glycolaldehyde and its conversion to glycolate has also been reported in the aerobic metabolism of D-arabinose [6].…”

“…In this metabolic pathway, the enzyme oxidizes glycolaldehyde to glycolate. The formation of glycolaldehyde and its conversion to glycolate has also been reported in the aerobic metabolism of D-arabinose [6].Lastly, Baldoma and Aguilar [2] have described that ALDH is induced in wild-type E. coli by the addition of glutamate to late-exponential-phase cultures grown on glycerol, although in this ca \e inducer molecule and the mechanism in Iolved are not known. Veither succin+ semialdehyde nor glulamic 4-semialdehyde, both intermediare aldehydes in pathways derived from glutamate, was found to be inducer or substrate of the dehydrogenase [2, 71.…”

Description of Schaedlerella arabinophila gen. nov., sp. nov., a D-arabinose utilizing bacterium isolated from feces of C57BL/6J mice and a close relative of Clostridium sp. ASF 502

“…Although the total number of selected colonies may be too small to be conclusive about how selective the medium is towards TLL-A1 isolation, the results indicate that either the growth conditions are only suitable for TLL-A1, or that the diversity of D-arabinose utilizers in the murine gut is low. The exact mechanism of D-arabinose utilization by TLL-A1 remains to be elucidated through follow-up analysis, but it is has been shown for other organisms, such as E. coli , that growth may occur via a L-fucose degradation pathway (21). Considering that fucose is a common component of host glycans (22), together with the finding that the S. arabinophila genomes encode for a large repertoire of CAZymes, it seems plausible that S. arabinophila may be able to utilize a similar pathway for growth.…”

Peer Review #2 of "Genomic and functional analysis of Romboutsia ilealis CRIBT reveals adaptation to the small intestine (v0.1)"

“…For these different carbohydrates, the genes encoding the specific carbohydrate degradation enzymes were found distributed throughout the genome in Manuscript to be reviewed carbohydrate utilized by R. ilealis CRIB T that was not predicted based on the metabolic model, was D-arabinose. Although a separate arabinose transporter, similar to the maltose and sucrose transporters, could be identified in the genome R. ilealis CRIB T , no separate pathway for the use of D-arabinose could be predicted, However, it is likely that the L-fucose degradation pathway (encoded by genes CRIB_1294-CRIB_1298) is also used for D-arabinose utilization as is also observed in other intestinal species (LeBlanc & Mortlock 1971). In addition to the carbohydrates for which growth was studied, a gene cluster involved in the degradation of the host-derived carbohydrate sialic acid could be predicted (CRIB_613-CRIB_619) (Almagro-Moreno & Boyd 2009).…”