Stoichiometry of lipid–protein interaction assessed by hydrophobic photolabeling

• Published in: FEBS letters 2006-01, Vol.580 (2), p.607-612
• Main Authors: Giraldo, Ana María Villamil, Castello, Pablo Raúl, Flecha, F. Luis González, Moeller, Jesper V., Delfino, José María, Rossi, Juan Pablo F.C.
• Format: Article
• Language: English
• Subjects: Animals; Calcium-Transporting ATPases - metabolism; Cation Transport Proteins - metabolism; Detergents - chemistry; Humans; Light; Lipids - chemistry; Lipid–protein interactions; Molecular Structure; P-type ATPases; Phosphatidylcholines - metabolism; Photoactivatable phospholipid; Plasma membrane calcium pump; Plasma Membrane Calcium-Transporting ATPases; PMCA; Rabbits; sarcoplasmic reticulum calcium pump; Sarcoplasmic Reticulum Calcium-Transporting ATPases; SERCA; Sodium pump; Sodium-Potassium-Exchanging ATPase - metabolism; Staining and Labeling - methods; Swine
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/j.febslet.2005.12.078

Here we undertook a comparative study of the composition of the lipid annulus of three ATPases pertaining to the P-type family: plasma membrane calcium pump (PMCA), sarcoplasmic reticulum calcium pump (SERCA) and Na,K-ATPase. The photoactivatable phosphatidylcholine analogue [ 125I]TID-PC/16 was incorporated into mixtures of dimyristoyl phosphatidylcholine (DMPC) and each enzyme with the aid of the nonionic detergent C 12E 10. After photolysis, the extent of the labeling reaction was assessed to determine the lipid:protein stoichiometry: 17 for PMCA, 18 for SERCA, 24 for the Na,K-ATPase (α-subunit) and 5.6 mol PC/mol protein for the Na,K-ATPase (β-subunit).