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Reconstitution of the solubilized cardiac sarcoplasmic reticulum potassium channel Identification of a putative M r ∼80 kDa polypeptide constituent
Author(s) -
Liu Qi-Yi,
Lai F.Anthony,
Shen Win K.,
Meissner Gerhard,
Strauss Harold C.
Publication year - 1991
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(91)81092-m
Subject(s) - solubilization , endoplasmic reticulum , potassium , chemistry , potassium channel , biochemistry , identification (biology) , biophysics , biology , organic chemistry , botany
Recent evidence has indicated that potassium ion movement through sarcoplasmic reticulum (SR) K + channels is an important countercurrent for Ca 2+ release from SR. We used Chaps‐solubilized SR vesicles and sucrose density gradient centrifugation to identify components of the canine cardiac SR K + channel. To overcome the difficulty of the absence of a high‐affinity specific ligand, we have successfully applied the planar lipid bilayer reconstitution technique to identify and functionally assay for the solubilized SR K + channel. We found that Chaps solubilization of the channel did not change the protein's functional properties. The cardiac SR K + channel sediments as a 15–20S protein complex. A polypeptide of M r ∼80 kDa was found to specifically comigrate with the 15–20S gradient fractions and might be a major constituent of the cardiac SR K + channel.