Premium
Structure of the extra‐membranous domain of the β‐subunit of (Na,K)‐ATPase revealed by the sequences of its tryptic peptides
Author(s) -
Ohta Toshiko,
Yoshida Masasuke,
Nagano Kei,
Hirano Hideyasu,
Kawamura Masaru
Publication year - 1986
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(86)80832-8
Subject(s) - trypsin , protein subunit , biochemistry , peptide sequence , chemistry , atpase , sequence (biology) , peptide , enzyme , biology , microbiology and biotechnology , gene
Membrane bound dog kidney (Na,K)‐ATPase was digested with trypsin. The peptides that were recovered in the supernatant were purified and sequenced. By comparing these results with the sequence of α‐ and human β‐subunits, the location of each of the peptides could be allotted. Both accessibility to trypsin and the facility of release into the water phase indicated that these peptides were derived from the exposed surface of the intact enzyme. The sequence, GXGXXG, reported in the Torpedo californica β‐subunit [(1986) FEBS Lett. 196, 315‐319] was likely a mere coincidence with the sequence of the dinucleotide‐binding site, since the last glycine was replaced by proline in the sequence of the dog β‐subunit. A disulfide bridge was found within a peptide derived from the β‐subunit. A possible model for the β‐subunit structure is proposed.