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Binding of monovalent cations induces large changes in the secondary structure of Na + ,K + ‐ATPase as probed by Raman spectroscopy
Author(s) -
Nabiev I.R.,
Dzhandzhugazyan K.N.,
Efremov R.G.,
Modyanov N.N.
Publication year - 1988
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 - 10.1016/0014-5793(88)80321-1
Subject(s) - chemistry , crystallography , raman spectroscopy , enzyme , protein subunit , atpase , stereochemistry , biochemistry , physics , optics , gene
Raman spectra of active Na + ,K + ‐ATPase from pig kidney in media containing Na + (E 1 ), K + (E 2 ) or without exogenous ions (E 1 conformation) were recorded in order to calculate the changes in the enzyme's secondary structure induced by binding of monovalent cations. It is demonstrated that: (i) K + binding to the E 1 form of the enzyme leads to conversion of100 peptide groups from the β‐structure to α‐helical conformation; (ii) the transition is reversible and fully reproducible in the E 1 →E 2 →E 1 and E 2 →E 1 →E 2 experimental schemes. Predictional calculations revealed polypeptide chain segments involved in the α ↔ β transformations. These segments reside mainly in the two highly conserved regions of the α‐subunit in the cytoplasmic domain of Na + ,K + ‐ATPase. A possible role for the β‐subunit is discussed.