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Science 305 (5690): 1573-1574

Copyright © 2004 by the American Association for the Advancement of Science

The Atomic Architecture of a Gas Channel

Mark A. Knepper and Peter Agre

Both prokaryotic and eukaryotic cells need to be able to transport ammonia gas. In their Perspective, Knepper and Agre discuss an exciting study (Khademi et al.) that reports resolution of the crystallographic structure of a bacterial ammonia transport channel, AmtB, to an astonishing 1.35 angstroms, an amazing feat for an integral membrane protein. The structure reveals how ammonia is transported in bacteria and sheds light on how related ammonia transport proteins work in eukaryotic cells.

M. A. Knepper is in the Laboratory of Kidney and Electrolyte Metabolism, National Institutes of Health, Bethesda, MD 20892, USA. E-mail: pagre{at}

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