cDNA cloning and membrane topology of the rabbit gastric H+/K(+)-ATPase alpha-subunit.
We have cloned and sequenced a cDNA for the rabbit gastric proton-potassium pump (H+/K(+)-ATPase) alpha-subunit. The deduced peptide contains 1035 amino acids (Mr 114,201) and shows 97% sequence identity with the respective rat and hog proteins. A monoclonal antibody 146-14 has been shown previously to react with the extracytoplasmic side of the catalytic H+/K(+)-ATPase subunit and here we show that the epitope is in the region between amino acids 855 and 902 (the numbering of the H+/K(+)-ATPase catalytic subunit throughout the paper refers to the rabbit sequence). The localization of this epitope in conjunction with previously observed trypsin cleavage sites in the C-terminal one third of the enzyme and the hydrophobicity plot of the deduced peptide sequence are evidence for a structural model for the alpha-subunit of the H+/K(+)-ATPase which contains at least ten membrane spanning segments, similar to that deduced for the Ca(2+)-ATPase of sarcoplasmic reticulum.
Bamberg
K
K
Department of Physiology, School of Medicine, UCLA.
Mercier
F
F
Reuben
M A
MA
Kobayashi
Y
Y
Munson
K B
KB
Sachs
G
G
D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D004247:DNA / Q000096:biosynthesis*; D015342:DNA Probes; D005753:Gastric Mucosa / Q000737:chemistry / Q000201:enzymology*; D015723:Gene Library; D017506:H(+)-K(+)-Exchanging ATPase; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis; D016133:Polymerase Chain Reaction; D011817:Rabbits; D051381:Rats; D013552:Swine; D014357:Trypsin
D015342:DNA Probes; D010446:Peptide Fragments; D004247:DNA; D014357:Trypsin; D000251:Adenosine Triphosphatases; D017506:H(+)-K(+)-Exchanging ATPase