A study on L-threonine and L-serine uptake in Escherichia coli K-12

Khozov, A.A.; Bubnov, D.M.; Plisov, E.D.; Vybornaya, T.V.; Yuzbashev, T.V.; Agrimi, G.; Messina, E.; Stepanova, A.A.; Kudina, M.D.; Alekseeva, N.V.; Netrusov, A.I.; Sineoky, S.P.

Авторы: Khozov A.A., Bubnov D.M., Plisov E.D., Vybornaya T.V., Yuzbashev T.V., Agrimi G., Messina E., Stepanova A.A., Kudina M.D., Alekseeva N.V., Netrusov A.I., Sineoky S.P.
Журнал: Frontiers in microbiology
Том: 14
Год издания: 2023
Издательство: Frontiers Research Foundation
Местоположение издательства: Switzerland
Первая страница: 1151716
Последняя страница: 1151716
Номер статьи: 1151716
DOI: 10.3389/fmicb.2023.1151716
Аннотация: In the current study, we report the identification and characterization of the yifKgene product as a novel amino acid carrier in E. coli K-12 cells. Both phenotypicand biochemical analyses showed that YifK acts as a permease specific toL-threonine and, to a lesser extent, L-serine. An assay of the effect of uncouplersand composition of the reaction medium on the transport activity indicates thatYifK utilizes a proton motive force to energize substrate uptake. To identify theremaining threonine carriers, we screened a genomic library prepared fromthe yifK-mutant strain and found that brnQ acts as a multicopy suppressor ofthe threonine transport defect caused by yifK disruption. Our results indicatethat BrnQ is directly involved in threonine uptake as a low-affinity but high-fluxtransporter, which forms the main entry point when the threonine concentrationin the external environment reaches a toxic level. By abolishing YifK and BrnQactivity, we unmasked and quantified the threonine transport activity of theLIV-I branched chain amino acid transport system and demonstrated that LIV-Icontributes significantly to total threonine uptake. However, this contribution islikely smaller than that of YifK. We also observed the serine transport activity ofLIV-I, which was much lower compared with that of the dedicated SdaC carrier,indicating that LIV-I plays a minor role in the serine uptake. Overall, these findingsallow us to propose a comprehensive model of the threonine/serine uptakesubsystem in E. coli cells
Добавил в систему: Нетрусов Александр Иванович

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A study on L-threonine and L-serine uptake in Escherichia coli K-12статья

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