Download MendeleyAlternating access in maltose transporter mediated by rigid-body rotations.
Khare, D., Oldham, M.L., Orelle, C., Davidson, A.L., Chen, J.(2009) Mol Cell 33: 528-536
- PubMed: 19250913
- DOI: https://doi.org/10.1016/j.molcel.2009.01.035
- Primary Citation of Related Structures:
3FH6 - PubMed Abstract:
ATP-binding cassette transporters couple ATP hydrolysis to substrate translocation through an alternating access mechanism, but the nature of the conformational changes in a transport cycle remains elusive. Previously we reported the structure of the maltose transporter MalFGK(2) in an outward-facing conformation in which the transmembrane (TM) helices outline a substrate-binding pocket open toward the periplasmic surface and ATP is poised for hydrolysis along the closed nucleotide-binding dimer interface. Here we report the structure of the nucleotide-free maltose transporter in which the substrate binding pocket is only accessible from the cytoplasm and the nucleotide-binding interface is open. Comparison of the same transporter crystallized in two different conformations reveals that alternating access involves rigid-body rotations of the TM subdomains that are coupled to the closure and opening of the nucleotide-binding domain interface. The comparison also reveals that point mutations enabling binding protein-independent transport line dynamic interfaces in the TM region.
Organizational Affiliation:
Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA.
