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Biochemical and Structural Characterization of the Carbohydrate Transport Substrate-binding-protein SP0092
Published on: October 2, 2017
The sodium/galactose symporter crystal structure is a dynamic, not so occluded state
1Department of Computational Biology, School of Medicine, University of Pittsburgh, 3064 BST3, 3501 Fifth Ave, Pittsburgh, PA 15213, USA. enz1@pitt.edu
Molecular Biosystems
|April 2, 2010
Summary
Molecular dynamics simulations reveal how the sodium/galactose symporter (vSGLT) transports galactose and sodium ions. Key residues and dynamic interactions are identified, offering insights into transporter function.
Area of Science:
- Structural biology
- Biochemistry
- Computational biology
Background:
- The sodium/galactose symporter (vSGLT) from Vibrio parahaemolyticus shares core architecture with other transporters like LeuT.
- vSGLT is uniquely crystallized in a substrate-bound, inward-facing conformation.
Purpose of the Study:
- To investigate the dynamics and coordination of galactose and sodium ions in vSGLT.
- To identify key residues and mechanisms involved in substrate and ion transport.
Main Methods:
- Utilized molecular dynamics simulations totaling approximately 0.1 microseconds.
- Analyzed interactions between ions, substrate, and transporter residues.
Main Results:
- Identified novel residues interacting with Na+ and galactose.
- Demonstrated Na+ ion can escape to the intracellular space from the crystallized conformation.
- Identified Asp189 as a likely Na+ binding residue on the intracellular pathway.
- Showed galactose release involves Tyr263 rotation without major backbone changes.
- Revealed the crystal structure represents one of many dynamic binding poses.
Conclusions:
- vSGLT dynamics reveal a flexible binding pocket with versatile interactions.
- The study provides a deeper understanding of sodium-galactose symporter mechanism and ion translocation.
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