An approach to membrane protein structure without crystals

Paul L. Sorgen, Yonglin Hu, Lan Guan, H. Ronald Kaback, Mark E. Girvin

Research output: Contribution to journalArticlepeer-review

82 Scopus citations


The lactose permease of Escherichia coli catalyzes coupled translocation of galactosides and H+ across the cell membrane. It is the best-characterized member of the Major Facilitator Superfamily, a related group of membrane proteins with 12 transmembrane domains that mediate transport of various substrates across cell membranes. Despite decades of effort and their functional importance in all kingdoms of life, no high-resolution structures have been solved for any member of this family. However, extensive biochemical, genetic, and biophysical studies on lactose permease have established its transmembrane topology, secondary structure, and numerous interhelical contacts. Here we demonstrate that this information is sufficient to calculate a structural model at the level of helix packing or better.

Original languageEnglish (US)
Pages (from-to)14037-14040
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number22
StatePublished - Oct 29 2002
Externally publishedYes


  • Bioenergetics
  • Engineered divalent metal-binding sites
  • Lactose permease
  • Membrane transport
  • Site-directed thiol cross-linking

ASJC Scopus subject areas

  • General


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