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Trehalose acts as a uridine 5′‐diphosphoglucose‐competitive inhibitor of trehalose 6‐phosphate synthase in Corynebacterium glutamicum
Author(s) -
Oide Shinichi,
Inui Masayuki
Publication year - 2017
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.14309
Subject(s) - trehalose , corynebacterium glutamicum , biology , biochemistry , corynebacterium , bacteria , atp synthase , phosphate , enzyme , gene , genetics
Trehalose is a compatible solute widely distributed in nature. The most prevalent pathway for its synthesis starts from condensation of glucose 6‐phosphate (Glc6 P ) and uridine 5′‐diphosphoglucose ( UDP ‐Glc) catalyzed by trehalose 6‐phosphate synthase ( TPS ). A previous laboratory evolution experiment with the bacterium Corynebacterium glutamicum generated strains adapted to supraoptimal temperatures, and the R328H substitution of the TPS encoded by otsA was shown to be associated with thermotolerance acquired by the evolved strains. In this study, we found that the OtsA:R328H substitution promotes both intra‐ and extracellular trehalose accumulation and demonstrated that build‐up of intracellular trehalose accounts for the Ots A R 328H ‐dependent thermotolerance, using the mycobacterial trehalose‐specific transporter. Counterintuitively, characterization of the recombinant OtsA proteins revealed that the mutation downshifts the temperature optimum of OtsA. A search for the molecular basis of Ots A R 328H ‐dependent enhancement of trehalose synthesis led to the unexpected findings that trehalose is an effective inhibitor of OtsA and that Ots A R 328H is highly tolerant to the trehalose‐mediated inhibition. The only available report on such feedback regulation of TPS is for the silk moth from over 50 years ago [Murphy TA and Wyatt GR (1965) J Biol Chem 240, 1500–1508]. While trehalose acts as a Glc6 P ‐competitive inhibitor in the silk moth, the disaccharide was found to inhibit OtsA in a UDP ‐Glc‐competitive manner in C. glutamicum , suggesting independent origins of the negative feedback regulations found for the two species. We showed that overexpression of the wild‐type OtsA counteracts the trehalose‐dependent regulation and restores the evolved strain‐like phenotype to the isogenic wild‐type otsA revertant, demonstrating that thermotolerance conferred by Ots A R 328H is attributable to its feedback‐resistant property.