The behaviors of Ca(2+)-ATPase embedded in interdigitated bilayer.
We investigated the behavior of a membrane protein, Ca(2+)-ATPase, in interdigitated phospholipid bilayers. The results showed that Ca(2+)-ATPase does not cause significant alterations in the interdigitation of 16:0 LPC/DPPC (27.0 mol% LPC) vesicles when it is reconstituted with lipids. Intrinsic fluorescence, acrylodan fluorescent adducts, and CD spectra indicated that Ca(2+)-ATPase, when embedded in interdigitated bilayer structures, is more exposed to the hydrophilic environment and has a looser structure than when embedded in non-interdigitated bilayers. The interdigitation of acyl chains induces a rapid loss of enzyme activity. It is suggested that interdigitated bilayer structures may play an important role as negative regulatory factors in physiological functions.
Lu
J Z
JZ
National Laboratory of Biomacromolecules, Institute of Biophysics, Academia Sinica, Beijing, 100101, China.
Huang
F
F
Chen
J W
JW
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry; D000818:Animals; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002942:Circular Dichroism; D005454:Fluorescence Polarization; D008051:Lipid Bilayers / Q000378:metabolism*; D011510:Proteolipids / Q000378:metabolism; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology; D013050:Spectrometry, Fluorescence; D013696:Temperature
D008051:Lipid Bilayers; D011510:Proteolipids; C020485:proteoliposomes; D015060:1,2-Dipalmitoylphosphatidylcholine; D000252:Calcium-Transporting ATPases