Functional significance of quaternary organization of the sarcoplasmic reticulum Ca2+-ATPase.
There is both structural and functional evidence for protein-protein interaction between Ca2+-ATPase polypeptide chains in the sarcoplasmic reticulum membrane. Studies on detergent solubilized ATPase indicate that the monomeric form is capable of performing a normal cycle of ATP hydrolysis, but some of the modulatory effects of the substrates disappear after detergent solubilization. However, the necessity of protein-protein interactions for the Ca2+ transport function remains unclarified. A new approach is described, employing ATPase reconstituted with a large excess of phospholipid, which may help to resolve this question.
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001693:Biological Transport, Active; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D007700:Kinetics; D046911:Macromolecular Substances; D010713:Phosphatidylcholines / Q000494:pharmacology; D011487:Protein Conformation; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*
D046911:Macromolecular Substances; D010713:Phosphatidylcholines; D000255:Adenosine Triphosphate; D000252:Calcium-Transporting ATPases; D002118:Calcium