Functionally important amino acids in rice sucrose transporter OsSUT1

Ye Sun, Zi Lin, Anke Reinders, John M. Ward

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Six conserved, charged amino acids within membrane spans in rice sucrose transporter OsSUT1 were identified using a three-dimensional structural model based on the crystal structures of three major facilitator superfamily (MFS) proteins: LacY, GlpT, and EmrD. These positions in OsSUT1 were selected for mutagenesis and biochemical assays. Among the six mutants, D177N completely lost transport function, D331N retained only a small fraction of sucrose uptake activity (2.3% of that of the wild type), and R335H and E336Q also displayed a substantial decrease in transport activity. D329N functioned as well as wild-type OsSUT1. R188K did not transport sucrose but showed a H+ leak that was inhibited by sucrose, indicating that R188K had uncoupled sucrose and H+ translocation. This demonstrates that charged amino acids within membrane spans are important for the transport mechanism of OsSUT1 as they are in lactose permease.

Original languageEnglish (US)
Pages (from-to)3284-3291
Number of pages8
JournalBiochemistry
Volume51
Issue number15
DOIs
StatePublished - Apr 17 2012

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Sucrose
Amino Acids
Membranes
Mutagenesis
Structural Models
Assays
Crystal structure
Oryza
lactose permease

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Functionally important amino acids in rice sucrose transporter OsSUT1. / Sun, Ye; Lin, Zi; Reinders, Anke; Ward, John M.

In: Biochemistry, Vol. 51, No. 15, 17.04.2012, p. 3284-3291.

Research output: Contribution to journalArticle

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