Calcium ATPase and Beryllium Fluoride
Sarco(endo)plasmic reticulum Ca2+-ATPase, calcium pump, catalyzes Ca2+ transport coupled with ATP hydrolysis into the lumen against ∼10,000 time concentration gradient. The ATPase is activated by high-affinity binding of two cytoplasmic Ca2+ ions at the transport sites in the transmembrane region and forms an autophosphorylated intermediate by transferring ATP γ-phosphate to a catalytic aspartate (Asp351) in the cytoplasmic region. The subsequent large conformational change disrupts the Ca2+ binding sites and releases Ca2+ into the lumen and produces the catalytic site for hydrolysis of the Asp351-phosphate bond. Beryllium in beryllium fluoride (BeF3−) compound is directly ligated with the catalytic aspartyl oxygen, producing a very stable analog of the covalently bound phosphate at Asp351 with an equivalent tetrahedral structure and bond lengths. The biochemical studies of the Ca2+-ATPase/BeF3− complexes with and without bound Ca2+at the transport...
- Danko S, Yamasaki K, Daiho T, Suzuki H (2004) Distinct natures of beryllium fluoride-bound, aluminum fluoride-bound, and magnesium fluoride-bound stable analogues of an ADP-insensitive phosphoenzyme intermediate of sarcoplasmic reticulum Ca2+-ATPase CHANGES IN CATALYTIC AND TRANSPORT SITES DURING PHOSPHOENZYME HYDROLYSIS. J Biol Chem 279:14991–14998CrossRefPubMedGoogle Scholar