title: Common folds and transport mechanisms of secondary active transporters.
abstract: Secondary active transporters exploit the electrochemical potential of solutes to shuttle specific substrate molecules across biological membranes, usually against their concentration gradient. Transporters of different functional families with little sequence similarity have repeatedly been found to exhibit similar folds, exemplified by the MFS, LeuT, and NhaA folds. Observations of multiple conformational states of the same transporter, represented by the LeuT superfamily members Mhp1, AdiC, vSGLT, and LeuT, led to proposals that structural changes are associated with substrate binding and transport. Despite recent biochemical and structural advances, our understanding of substrate recognition and energy coupling is rather preliminary. This review focuses on the common folds and shared transport mechanisms of secondary active transporters. Available structural information generally supports the alternating access model for substrate transport, with variations and extensions made by emerging structural, biochemical, and computational evidence.
authors: Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Joint Center for Life Sciences, Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China. shi-lab@tsinghua.edu.cn
authors: Yigong
authors: Y
authors: Shi
mesh_terms: D000818:Animals; D001419:Bacteria / Q000737:chemistry / Q000378:metabolism; D001671:Biochemistry / Q000379:methods; D001692:Biological Transport; D006801:Humans; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D017510:Protein Folding
chemical_list: D026901:Membrane Transport Proteins