Open AccessResidues in the pathway through a membrane transporter.
Author(s) -
RunTao Yan,
Peter C. Maloney
Publication year - 1995
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.92.13.5973
Subject(s) - transporter , transmembrane protein , cysteine , mutagenesis , transmembrane domain , membrane , biochemistry , amino acid , helix (gastropod) , chemistry , biophysics , chromosomal translocation , biology , mutation , gene , receptor , enzyme , ecology , snail
The structure of solute transporters is understood largely from analysis of their amino acid sequences, and more direct information is greatly needed. Here we report work that applies cysteine scanning mutagenesis to describe structure-function relations in UhpT, a bacterial membrane transporter. By using an impermeant SH-reactive agent to probe single-cysteine variants, we show that UhpT transmembrane segment 7 spans the membrane as an alpha-helix and that the central portion of this helix is exposed to both membrane surfaces, forming part of the translocation pathway through this transporter.