NMR studies of the fifth transmembrane segment of Na+,K+-ATPase reveals a non-helical ion-binding region

Jarl Underhaug, Louise Odgaard Jakobsen, Mikael Esmann, Anders Malmendal, Niels Chr Nielsen

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review


The structure of a synthetic peptide corresponding to the fifth membrane-spanning segment (M5) in Na(+),K(+)-ATPase in sodium dodecyl sulfate (SDS) micelles was determined using liquid-state nuclear magnetic resonance (NMR) spectroscopy. The spectra reveal that this peptide is substantially less alpha-helical than the corresponding M5 peptide of Ca(2+)-ATPase. A well-defined alpha-helix is shown in the C-terminal half of the peptide. Apart from a short helical stretch at the N-terminus, the N-terminal half contains a non-helical region with two proline residues and sequence similarity to a non-structured transmembrane element of the Ca(2+)-ATPase. Furthermore, this region spans the residues implicated in Na(+) and K(+) transport, where they are likely to offer the flexibility needed to coordinate Na(+) as well as K(+) during active transport.

TidsskriftF E B S Letters
Udgave nummer20
Sider (fra-til)4777-83
Antal sider7
StatusUdgivet - 4 sep. 2006
Udgivet eksterntJa

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