Novel inositol catabolic pathway in Thermotoga maritima

Summary myo‐inositol (MI) is a key sugar alcohol component of various metabolites, e.g. phosphatidylinositol‐based phospholipids that are abundant in animal and plant cells. The seven‐step pathway of MI degradation was previously characterized in various soil bacteria including Bacillus subtilis. Th...

Full description

Saved in:
Bibliographic Details
Published in:Environmental microbiology 2013-08, Vol.15 (8), p.2254-2266
Main Authors: Rodionova, Irina A., Leyn, Semen A., Burkart, Michael D., Boucher, Nathalie, Noll, Kenneth M., Osterman, Andrei L., Rodionov, Dmitry A.
Format: Article
Language:English
Subjects:
Bacillus subtilis
Bacillus subtilis - enzymology
Bacillus subtilis - genetics
Bacteriology
Dehydrogenases
Enzymes - genetics
Enzymes - metabolism
Gene Order
Hydrolysis
Inositol - chemistry
Inositol - metabolism
Microbiology
Multigene Family
Protein Binding
Substrate Specificity
Thermotoga
Thermotoga maritima
Thermotoga maritima - enzymology
Thermotoga maritima - genetics
Thermotoga maritima - metabolism
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Summary myo‐inositol (MI) is a key sugar alcohol component of various metabolites, e.g. phosphatidylinositol‐based phospholipids that are abundant in animal and plant cells. The seven‐step pathway of MI degradation was previously characterized in various soil bacteria including Bacillus subtilis. Through a combination of bioinformatics and experimental techniques we identified a novel variant of the MI catabolic pathway in the marine hyperthermophilic bacterium Thermotoga maritima. By using in vitro biochemical assays with purified recombinant proteins we characterized four inositol catabolic enzymes encoded in the TM0412–TM0416 chromosomal gene cluster. The novel catabolic pathway in T. maritima starts as the conventional route using the myo‐inositol dehydrogenase IolG followed by three novel reactions. The first 2‐keto‐myo‐inositol intermediate is oxidized by another, previously unknown NAD‐dependent dehydrogenase TM0412 (named IolM), and a yet unidentified product of this reaction is further hydrolysed by TM0413 (IolN) to form 5‐keto‐l‐gluconate. The fourth step involves epimerization of 5‐keto‐l‐gluconate to d‐tagaturonate by TM0416 (IolO). T. maritima is unable to grow on myo‐inositol as a single carbon source. The determined in vitro specificity of the InoEFGK (TM0418–TM0421) transporter to myo‐inositol‐phosphate suggests that the novel pathway in Thermotoga utilizes a phosphorylated derivative of inositol.
ISSN:1462-2912
1462-2920
DOI:10.1111/1462-2920.12096