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Structural insight into glucose repression of the mannitol operon
Mangyu Choe1, Huitae Min1, Young-Ha Park1
1School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul, 00826, Korea.
Scientific Reports
|September 28, 2019
Summary
Glucose preference over mannitol in E. coli is regulated by the MtlR-HPr interaction. Phosphorylation of HPr hinders this interaction, ensuring sequential carbohydrate use.
Area of Science:
- Microbiology
- Molecular Biology
- Structural Biology
Background:
- Carbon catabolite repression ensures sequential carbohydrate utilization.
- Glucose represses mannitol transport/metabolism via MtlR in E. coli, despite shared PTS components.
Purpose of the Study:
- Determine the structural basis of glucose preference over mannitol.
- Understand how HPr phosphorylation affects MtlR interaction.
Main Methods:
- X-ray crystallography of the MtlR-HPr complex (3.5 Å resolution).
- Comparative sequence analysis.
Main Results:
- Identified dephosphorylated HPr as the regulator for glucose preference.
- Structural data reveals His15 phosphorylation on HPr causes electrostatic repulsion with MtlR.
- Phosphorylation site (His15) is near MtlR residues Glu108 and Glu140.
Conclusions:
- Structural insights explain how HPr phosphorylation impedes MtlR interaction.
- MtlR-HPr interaction mechanism for glucose preference is conserved in Enterobacteriaceae.
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