Editors' ChoiceStructural Biology

Pumping Uphill

Science's STKE  11 Sep 2001:
Vol. 2001, Issue 99, pp. tw328
DOI: 10.1126/stke.2001.99.tw328

The ABC transporters, one of the largest classes of membrane proteins engaged in active (energetically uphill) transport, contain a cytoplasmically disposed adenosine triphosphate (ATP)-binding cassette linked to what has been predicted to be a bundle of transmembrane helices (see the Perspective by Higgins and Linton). The subgroup of multidrug resistance (MDR) transporters use the energy from ATP hydrolysis to pump a broad spectrum of hydrophobic drugs out of cells. Chang and Roth have determined the crystal structure at 4.5 angstroms of MsbA, a bacterial ABC transporter that has strong sequence similarity with MDR proteins. Two six-helix bundles form an inverted V-shaped, intramembrane transport chamber. The authors propose that accessibility to this chamber is regulated cyclically via hydrolysis of ATP at the two globular ABC domains.

C. F. Higgins, K. J. Linton, The xyz of ABC transporters. Science 293, 1782-1784 (2001). [Full Text]

G. Chang, C. B. Roth, Structure of MsbA from E. coli: A homolog of the multidrug resistance ATP binding cassette (ABC) transporters. Science 293, 1793-1800 (2001). [Abstract] [Full Text]

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