Structural Biology

Proton/Protein Transport

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Science  06 Jul 2001:
Vol. 293, Issue 5527, pp. 17
DOI: 10.1126/science.293.5527.17b

In eukaryotic cells, F-type ATPases convert a mitochondrial proton gradient into ATP (the final stage in extracting energy from the oxidation of carbon compounds) while V-type ATPases use ATP to transport protons across internal membranes, notably in the acidification of lysosomes. Although these enzymes are similar in composition and function, there are specific components, such as the H subunit of the yeast V-ATPase, whose crystal structure Sagermann et al. describe. Much of the H subunit, an essential regulator of catalytic activity, is composed of a right-handed superhelix of α-helices that bears similarity to the importins (or karyopherins), which bind to proteins containing nuclear localization signals (NLS) and mediate transport of them into the nucleus. One end of the H subunit sits within what corresponds to the NLS peptide binding site of the importins; whether this relates to its regulatory role or to its interaction with other proteins is unclear. — GJC

Proc. Natl. Acad. Sci. U.S.A.98, 7134 (2001).

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