Biomaterial Database

Intersubunit and intrasubunit contact regions of Na+/K(+)-ATPase revealed by controlled proteolysis and chemical cross-linking. 1995

N A Sarvazyan, and N N Modyanov, and A Askari

Department of Pharmacology, Medical College of Ohio, Toledo 43699-0008, USA.

To identify interfaces of alpha- and beta-subunits of Na+/K(+)-ATPase, and contact points between different regions of the same alpha-subunit, purified kidney enzyme preparations whose alpha-subunits were subjected to controlled proteolysis in different ways were solubilized with digitonin to disrupt intersubunit alpha,alpha-interactions, and oxidatively cross-linked. The following disulfide cross-linked products were identified by gel electrophoresis, staining with specific antibodies, and N-terminal analysis. 1) In the enzyme that was partially cleaved at Arg438-Ala439, the cross-linked products were an alpha,beta-dimer, a dimer of N-terminal and C-terminal alpha fragments, and a trimer of beta and the two alpha fragments. 2) From an extensively digested enzyme that contained the 22-kDa C-terminal and several smaller fragments of alpha, two cross-linked products were obtained. One was a dimer of the 22-kDa C-terminal peptide and an 11-kDa N-terminal peptide containing the first two intramembrane helices of alpha (H1-H2). The other was a trimer of beta, the 11-kDa, and the 22-kDa peptides. 3) The cross-linked products of a preparation partially cleaved at Leu266-Ala267 were an alpha,beta-dimer and a dimer of beta and the 83-kDa C-terminal fragment. Assuming the most likely 10-span model of alpha, these findings indicate that (a) the single intramembrane helix of beta is in contact with portions of H8-H10 intramembrane helices of alpha; and (b) there is close contact between N-terminal H1-H2 and C-terminal H8-H10 segments of alpha; with the most probable interacting helices being the H1,H10-pair and the H2,H8-pair.

UI	MeSH Term	Description	Entries
D007679	Kidney Medulla	The internal portion of the kidney, consisting of striated conical masses, the renal pyramids, whose bases are adjacent to the cortex and whose apices form prominent papillae projecting into the lumen of the minor calyces.	Kidney Papilla,Kidney Medullas,Kidney Papillas,Medulla, Kidney,Medullas, Kidney,Papilla, Kidney,Papillas, Kidney
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
D010446	Peptide Fragments	Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.	Peptide Fragment,Fragment, Peptide,Fragments, Peptide
D010450	Endopeptidases	A subclass of PEPTIDE HYDROLASES that catalyze the internal cleavage of PEPTIDES or PROTEINS.	Endopeptidase,Peptide Peptidohydrolases
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D003300	Copper	A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.	Copper-63,Copper 63
D003432	Cross-Linking Reagents	Reagents with two reactive groups, usually at opposite ends of the molecule, that are capable of reacting with and thereby forming bridges between side chains of amino acids in proteins; the locations of naturally reactive areas within proteins can thereby be identified; may also be used for other macromolecules, like glycoproteins, nucleic acids, or other.	Bifunctional Reagent,Bifunctional Reagents,Cross Linking Reagent,Crosslinking Reagent,Cross Linking Reagents,Crosslinking Reagents,Linking Reagent, Cross,Linking Reagents, Cross,Reagent, Bifunctional,Reagent, Cross Linking,Reagent, Crosslinking,Reagents, Bifunctional,Reagents, Cross Linking,Reagents, Cross-Linking,Reagents, Crosslinking
D004285	Dogs	The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)	Canis familiaris,Dog
D000254	Sodium-Potassium-Exchanging ATPase	An enzyme that catalyzes the active transport system of sodium and potassium ions across the cell wall. Sodium and potassium ions are closely coupled with membrane ATPase which undergoes phosphorylation and dephosphorylation, thereby providing energy for transport of these ions against concentration gradients.	ATPase, Sodium, Potassium,Adenosinetriphosphatase, Sodium, Potassium,Na(+)-K(+)-Exchanging ATPase,Na(+)-K(+)-Transporting ATPase,Potassium Pump,Sodium Pump,Sodium, Potassium ATPase,Sodium, Potassium Adenosinetriphosphatase,Sodium-Potassium Pump,Adenosine Triphosphatase, Sodium, Potassium,Na(+) K(+)-Transporting ATPase,Sodium, Potassium Adenosine Triphosphatase,ATPase Sodium, Potassium,ATPase, Sodium-Potassium-Exchanging,Adenosinetriphosphatase Sodium, Potassium,Pump, Potassium,Pump, Sodium,Pump, Sodium-Potassium,Sodium Potassium Exchanging ATPase,Sodium Potassium Pump