Rubtsov A M, Iang L, Lopina O D, MacStay D, Quinn P J, Boldyrev A A
Department of Applied Sciences, Robert Gordon University, Aberdeen, Scotland.
Biokhimiia. 1994 Dec;59(12):1900-9.
The rotational mobility of E1 and E2 conformers of duck salt gland Na,K-ATPase labelled with eosine-5'-isothiocyanate (EITC) was studied using a time-resolved phosphorescence anisotropy approach. For each conformer, two types of the rotational mobility were found. The rotational correlation time of the faster component equal to about 15 microseconds at 20 degrees for the both conformers, was ascribed to the rotation of the (alpha beta) protomer with an apparent radius 2.4 nm. The slower component (100-500 microseconds depending on experimental conditions) was suggested to reflect the presence in the bilayer of associates between Na,K-ATPase molecules or those with other protein constituents of the membrane bilayer. A rise in temperature tends to decrease the fast component with a subsequent increase in the slow component of the experimental curve, apparently due to oligomerisation of the protomers into oligomers. The size of the oligomers depends on pH and temperature and under favourable conditions may come up to octamers.
利用时间分辨磷光各向异性方法研究了用异硫氰酸荧光素（EITC）标记的鸭盐腺钠钾-ATP酶E1和E2构象体的旋转流动性。对于每种构象体，发现了两种类型的旋转流动性。两种构象体在20℃时较快成分的旋转相关时间约为15微秒，这归因于（αβ）原聚体以2.4nm的表观半径旋转。较慢的成分（根据实验条件为100 - 500微秒）被认为反映了钠钾-ATP酶分子之间或与膜双层其他蛋白质成分在双层中的缔合存在。温度升高往往会使实验曲线的快速成分降低，随后慢速成分增加，这显然是由于原聚体寡聚成寡聚物所致。寡聚物的大小取决于pH值和温度，在有利条件下可能达到八聚体。
