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

TY - JOUR

T1 - NMR studies of the fifth transmembrane segment of Na+,K+-ATPase reveals a non-helical ion-binding region

AU - Underhaug, Jarl

AU - Jakobsen, Louise Odgaard

AU - Esmann, Mikael

AU - Malmendal, Anders

AU - Nielsen, Niels Chr

PY - 2006/9/4

Y1 - 2006/9/4

N2 - 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.

AB - 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.

KW - Amino Acid Sequence

KW - Humans

KW - Ions

KW - Models, Molecular

KW - Molecular Sequence Data

KW - Nuclear Magnetic Resonance, Biomolecular

KW - Peptides

KW - Potassium

KW - Protein Structure, Secondary

KW - Protein Structure, Tertiary

KW - Sodium

KW - Sodium-Potassium-Exchanging ATPase

U2 - 10.1016/j.febslet.2006.07.063

DO - 10.1016/j.febslet.2006.07.063

M3 - Journal article

C2 - 16904671

SN - 0014-5793

VL - 580

SP - 4777

EP - 4783

JO - F E B S Letters

JF - F E B S Letters

IS - 20

ER -