Chimeric rat Na,K-ATPase alpha 1/alpha 3* isoforms. Analysis of the structural basis for differences in Na+ requirements in the alpha 1 and alpha 3* isoforms.
Na,K-ATPase molecules containing the alpha 1, alpha 2*, and alpha 3* isoforms expressed in HeLa cells exhibit a two- to threefold difference in their K0.5 for Na+ (alpha 1 = alpha 2* < alpha 3*). To investigate the structural basis for this difference, chimeric alpha 1/alpha 3* isoform cDNAs were constructed and expressed in HeLa cells. Na,K-ATPase containing each alpha isoform chimera was analyzed for its Na+ dependence properties. Results of these experiments do not reveal a region in the alpha 1 or alpha 3* isoform that is clearly responsible for the apparent affinity for Na+. It is possible that molecular interactions involving amino acids that span virtually the entire Na,K-ATPase molecule contribute to the determination of this parameter.
Jewell
E A
EA
Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Ohio 45267-0524.
Lingrel
J B
JB
D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D003001:Cloning, Molecular; D006367:HeLa Cells; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D015202:Protein Engineering; D017433:Protein Structure, Secondary; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D015183:Restriction Mapping; D012964:Sodium / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
D011993:Recombinant Fusion Proteins; D012313:RNA; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase