Structural insight into glucose repression of the mannitol operon

Mangyu Choe, Huitae Min, Young Ha Park, Yeon Ran Kim, Jae Sung Woo, Yeong Jae Seok

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9 Citations (Scopus)


Carbon catabolite repression is a regulatory mechanism to ensure sequential utilization of carbohydrates and is usually accomplished by repression of genes for the transport and metabolism of less preferred carbon compounds by a more preferred one. Although glucose and mannitol share the general components, enzyme I and HPr, of the phosphoenolpyruvate-dependent phosphotransferase system (PTS) for their transport, glucose represses the transport and metabolism of mannitol in a manner dependent on the mannitol operon repressor MtlR in Escherichia coli. In a recent study, we identified the dephosphorylated form of HPr as a regulator determining the glucose preference over mannitol by interacting with and augmenting the repressor activity of MtlR in E. coli. Here, we determined the X-ray structure of the MtlR-HPr complex at 3.5 Å resolution to understand how phosphorylation of HPr impedes its interaction with MtlR. The phosphorylation site (His15) of HPr is located close to Glu108 and Glu140 of MtlR and phosphorylation at His15 causes electrostatic repulsion between the two proteins. Based on this structural insight and comparative sequence analyses, we suggest that the determination of the glucose preference over mannitol solely by the MtlR-HPr interaction is conserved within the Enterobacteriaceae family.

Original languageEnglish
Article number13930
JournalScientific reports
Issue number1
Publication statusPublished - 2019 Dec 1

Bibliographical note

Funding Information:
We thank Chaehee Park and Dr. Hee-jung Choi for their assistance in protein thermal stability measurements and Seu-Na Lee for assistance in SEC-MALS experiment and gel filtration chromatography. We also thank Debora Kang for critical reading of the manuscript. This work was supported by the Samsung Science and Technology Foundation under Project Number SSTF-BA1501-13 and National Research Foundation Grants NRF-2018R1A5A1025077 and NRF-2019R1A2C2004143 funded by the Ministry of Science and ICT (to Y.J.S.) and Korea University Grant (to J.S.W.).

Publisher Copyright:
© 2019, The Author(s).

ASJC Scopus subject areas

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