Premium
Projection structure and molecular architecture of OxlT, a bacterial membrane transporter
Author(s) -
Heymann Jürgen A.W.,
Sarker Rafiquel,
Hirai Teruhisa,
Shi Dan,
Milne Jacqueline L.S.,
Maloney Peter C.,
Subramaniam Sriram
Publication year - 2001
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/20.16.4408
Subject(s) - major facilitator superfamily , biology , projection (relational algebra) , transmembrane protein , transmembrane domain , superfamily , oxalate , membrane protein , transporter , membrane , membrane transport protein , protein structure , biophysics , crystallography , computational biology , biochemistry , computer science , physics , chemistry , algorithm , gene , receptor , nuclear physics
The major facilitator superfamily (MFS) represents the largest collection of evolutionarily related members within the class of membrane ‘carrier’ proteins. OxlT, a representative example of the MFS, is an oxalate‐transporting membrane protein in Oxalobacter formigenes . From an electron crystallographic analysis of two‐dimensional crystals of OxlT, we have determined the projection structure of this membrane transporter. The projection map at 6 Å resolution indicates the presence of 12 transmembrane helices in each monomer of OxlT, with one set of six helices related to the other set by an approximate internal two‐fold axis. The projection map reveals the existence of a central cavity, which we propose to be part of the pathway of oxalate transport. By combining information from the projection map with related biochemical data, we present probable models for the architectural arrangement of transmembrane helices in this protein superfamily.