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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
34
pubmed:dateCreated
2000-9-25
pubmed:abstractText
The Vibrio parahaemolyticus sodium/glucose transporter (vSGLT) is a bacterial member of the SGLT gene family. Wild-type and mutant vSGLT proteins were expressed in Escherichia coli, and transport activity was measured in intact cells and plasma membrane vesicles. Two cysteine-less vSGLT proteins exhibited sugar transport rates comparable with that of the wild-type protein. Six residues in two regions of vSGLT known to be of functional importance in SGLT1 were replaced individually with cysteine in the cysteine-less protein. Characterization of these single cysteine-substituted vSGLTs showed that two residues (Gly-151 and Gln-428) are essential for transport function, whereas the other four residues (Leu-147, Leu-149, Ala-423, and Gln-425) are not. 2-Aminoethylmethanethiosulfonate (MTSEA) blocked Na(+)/glucose transport by only the transporter bearing a cysteine at position 425 (Q425C). MTSEA inhibition was reversed by dithiothreitol and blocked by the presence of both Na(+) and d-glucose, indicating that conformational changes of the vSGLT protein are involved in Na(+)/glucose transport. A split version of vSGLT was generated by co-expression of the N-terminal (N(7)) and C-terminal (C(7)) halves of the transporter. The split vSGLT maintained Na(+)-dependent glucose transport activity. Chemical cross-linking of split vSGLT, with a cysteine in each N(7) and C(7) fragment, suggested that hydrophilic loops between helices 4 and 5 and between helices 10 and 11 are within 8 A of each other. We conclude that the mechanism of Na(+)/glucose transport by vSGLT is similar to mammalian SGLTs and that further studies on vSGLT will provide novel insight to the structure and function of this class of cotransporters.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
275
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
25959-64
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Characterization of the Vibrio parahaemolyticus Na+/Glucose cotransporter. A bacterial member of the sodium/glucose transporter (SGLT) family.
pubmed:affiliation
Department of Physiology, UCLA School of Medicine, Los Angeles, California 90095-1751, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.