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NMR studies of the fifth transmembrane segment of Na + ,K + ‐ATPase reveals a non‐helical ion‐binding region
Author(s) -
Underhaug Jarl,
Jakobsen Louise Odgaard,
Esmann Mikael,
Malmendal Anders,
Nielsen Niels Chr.
Publication year - 2006
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2006.07.063
Subject(s) - chemistry , peptide , transmembrane protein , crystallography , transmembrane domain , peptide sequence , nuclear magnetic resonance spectroscopy , sodium dodecyl sulfate , helix (gastropod) , stereochemistry , n terminus , amino acid , biochemistry , biology , ecology , receptor , snail , gene
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 α‐helical than the corresponding M5 peptide of Ca 2+ ‐ATPase. A well‐defined α‐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.