Document Detail


Model of the 3-D structure of the GLUT3 glucose transporter and molecular dynamics simulation of glucose transport.
MedLine Citation:
PMID:  11170207     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A molecular model of the three-dimensional (3-D) structure of the glucose transport protein, GLUT3, has been derived by homology modeling. The model was built on the basis of structural data from the MscL protein, which is a mechanosensitive ion channel, and general insights from aquaporin (a water permeation pore). Structurally conserved regions were defined by amino acid sequence comparisons, optimum interconnecting loops were selected from the protein databank, and amino (N)- and carboxy (C)-terminal ends of the protein were generated as random coil structures. The model was then subjected to energy minimization and molecular dynamics simulations in the presence of bound substrate (D-glucose). In the proposed structure of GLUT3, the 12 transmembrane (TM) helices form a right-hand barrel with a central hydrophilic pore. The pore is shaped like a funnel with dimensions of approximately 5-6 A by 8 A at its narrowest point. A network of polar and aromatic amino acids line the pore region and may facilitate the movement of glucose along the channel. A putative binding site for inhibitory ligands, such as forskolin and cytochalasin B, was identified on an intracellular aspect of the protein. Molecular dynamics studies showed that changes in the tilt and flexibility of key TM helices may modulate the opening of the pore to effect glucose transport. The proposed structure of GLUT3 may prove useful in guiding future experiments aimed at more precisely defining various functional regions of the transporter and may encourage efforts to develop models of other complex membrane proteins.
Authors:
D S Dwyer
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Proteins     Volume:  42     ISSN:  0887-3585     ISO Abbreviation:  Proteins     Publication Date:  2001 Mar 
Date Detail:
Created Date:  2001-02-22     Completed Date:  2001-04-26     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  8700181     Medline TA:  Proteins     Country:  United States    
Other Details:
Languages:  eng     Pagination:  531-41     Citation Subset:  IM    
Copyright Information:
Copyright 2001 Wiley-Liss, Inc.
Affiliation:
Departments of Psychiatry and Pharmacology, Louisiana State University Health Sciences Center, Shreveport 71130, USA. ddwyer@lsuhsc.edu
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MeSH Terms
Descriptor/Qualifier:
Amino Acid Sequence
Animals
Binding Sites
Biological Transport
Biophysical Phenomena
Biophysics
Escherichia coli Proteins*
Glucose / metabolism*
Glucose Transporter Type 3
Humans
Ion Channels / chemistry
Models, Molecular
Molecular Sequence Data
Molecular Structure
Monosaccharide Transport Proteins / chemistry*,  genetics,  metabolism
Nerve Tissue Proteins*
Protein Structure, Secondary
Protein Structure, Tertiary
Sequence Homology, Amino Acid
Thermodynamics
Water / chemistry
Chemical
Reg. No./Substance:
0/Escherichia coli Proteins; 0/Glucose Transporter Type 3; 0/Ion Channels; 0/Monosaccharide Transport Proteins; 0/MscL protein, E coli; 0/Nerve Tissue Proteins; 0/SLC2A3 protein, human; 50-99-7/Glucose; 7732-18-5/Water

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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