Structural insight into the PTS sugar transporter EIIC
Jason G McCoy1, Elena J Levin1, Ming Zhou1
1Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
Biochimica Et Biophysica Acta
|March 25, 2014
Summary
The enzyme IIB (EIIC) component of the phosphotransferase system (PTS) transports and phosphorylates sugars in bacteria. Structural analysis reveals conserved residues and domain motion critical for this selective sugar uptake process.
Area of Science:
- Membrane protein structure and function
- Bacterial sugar transport mechanisms
- Biochemistry and biophysics of membrane proteins
Background:
- The enzyme IIB (EIIC) component of the phosphotransferase system (PTS) facilitates selective sugar transport across bacterial membranes.
- Sugar phosphorylation by EIIC prevents efflux and is crucial for bacterial carbohydrate utilization and signaling.
Purpose of the Study:
- To review the structural features of EIIC and its role in concentrative, selective sugar transport.
- To use the N,N'-diacetylchitobiose transporter structure as a template for understanding the glucose superfamily of PTS transporters.
Main Methods:
- Comparative analysis of EIIC protein sequences.
- Utilizing crystal structure data of a related transporter as a model.
- Examining structural variations and conserved residues within the glucose superfamily.
Main Results:
- EIIC transporters within the glucose superfamily may display topological variations.
- Conserved histidine and glutamate residues are implicated in sugar binding and phosphorylation.
- A proposed transport model involves rigid body motion and loop movement for substrate access.
Conclusions:
- Preliminary understanding of EIIC transport mechanisms is established.
- Sequence diversity necessitates further structural studies of various EIIC members and conformations.
- Additional structural data is required to fully elucidate the conformational changes involved in transport.
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