Structure and molecular mechanism of a nucleobase-cation-symport-1 family transporter
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The nucleobase-cation-symport-1 (NCS1) transporters are essential components of salvage pathways for nucleobases and related metabolites. Here, we report the 2.85-angstrom resolution structure of the NCS1 benzyl-hydantoin transporter, Mhp1, from Microbacterium liquefaciens. Mhp1 contains 12 transmembrane helices, 10 of which are arranged in two inverted repeats of five helices. The structures of the outward-facing open and substrate-bound occluded conformations were solved, showing how the outward-facing cavity closes upon binding of substrate. Comparisons with the leucine transporter LeuT(Aa) and the galactose transporter vSGLT reveal that the outward- and inward-facing cavities are symmetrically arranged on opposite sides of the membrane. The reciprocal opening and closing of these cavities is synchronized by the inverted repeat helices 3 and 8, providing the structural basis of the alternating access model for membrane transport.
Original language | English |
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Journal | Science |
Volume | 322 |
Issue number | 5902 |
Pages (from-to) | 709-713 |
ISSN | 0036-8075 |
DOIs | |
Publication status | Published - 2008 |
Bibliographical note
Keywords: Actinomycetales; Amino Acid Sequence; Bacterial Proteins; Binding Sites; Cations; Cell Membrane; Crystallography, X-Ray; Hydantoins; Ion Transport; Models, Molecular; Molecular Sequence Data; Nucleobase Transport Proteins; Protein Conformation; Protein Structure, Secondary; Sodium; Symporters
- Former Faculty of Pharmaceutical Sciences
Research areas
ID: 10488112