Caldesmon from rabbit liver: molecular weight and length by analytical ultracentrifugation.
Caldesmon from rabbit liver: molecular weight and length by analytical ultracentrifugation.
复制标题
来自兔肝脏的卡尔德蒙：通过分析超速离心得到的分子量和长度。
DOI：
10.1016/0003-9861(90)90413-s
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发表时间：
1990
影响因子：
3.9
通讯作者：
Graceffa,P
中科院分区：
文献类型：
--
作者：
Stafford,WF;Jancso,A;Graceffa,P
虽然在十二烷基硫酸钠凝胶电泳过程中，平滑肌caldesmon以140- 150 kDa的蛋白质迁移，但通过沉降平衡测定，其分子质量约为93 kDa。王亚平，王志强，1988，J。医学杂志。Chem.263, 14196 - 14202)。非肌肉caldesmon在电泳过程中迁移，分子量接近77 kDa，约为肌肉同种异构体的一半。然而，非肌肉蛋白caldesmon的分子量是否与肌肉蛋白相同或远小于肌肉蛋白的分子量一直存在争议。因此，我们现在用沉降平衡法测定了兔肝胼胝体的分子质量，发现其值为66±2 kDa，远小于肌肉胼胝体的分子质量。这个新的分子量值加上2.49±0.02 S的沉降系数，使肝蛋白的表观长度为53±2 nm，直径为1.7 nm。我们先前估计肌肉胼胝体的长度为74 nm，直径为1.7 nm。我们还测定了肝磷脂的氨基酸组成，发现它与肌肉蛋白的氨基酸组成相似。总之，肌肉和非肌肉caldesmons似乎具有相似的整体氨基酸组成和三级结构，较小的非肌肉蛋白具有相应的较小长度。E. H. Ball和T. Kovala, 1988, biochemical 27,6093 - 6098指出，这两种caldesmons的分子量差异与非肌肉蛋白缺乏肌肉异构体的中心肽一致。
Although smooth muscle caldesmon migrates as a 140- to 150-kDa protein during sodium dodecyl sulfate-gel electrophoresis, its molecular mass is around 93 kDa as determined by sedimentation equilibrium (P. Graceffa, C-L. A. Wang, and W. F. Stafford, 1988,J. Biol. Chem.263, 14,196-14,202). Nonmuscle caldesmon migrates during electrophoresis with a molecular mass close to 77 kDa, about half that of the muscle isoform. However, it is controversial whether the molecular weight of nonmuscle caldesmon is the same or much less than that of the muscle protein. Therefore we have now determined the molecular mass of rabbit liver caldesmon by sedimentation equilibrium and found a value of 66 ± 2 kDa, a value much smaller than that of muscle caldesmon. This new value of the molecular weight, together with a sedimentation coefficient of 2.49 ± 0.02 S, yields an apparent length of 53 ± 2 nm and a diameter of 1.7 nm for the liver protein. We previously estimated a length of 74 nm and a diameter of 1.7 nm for the muscle caldesmon. We have also determined the amino acid composition of liver caldesmon and found it to be similar to that of the muscle protein. In conclusion, muscle and nonmuscle caldesmons appear to have similar overall amino acid composition and tertiary structure with the smaller nonmuscle protein having a correspondingly smaller length. The difference in molecular weight between the two caldesmons is consistent with the nonmuscle protein lacking a central peptide of the muscle isoform, as suggested by E. H. Ball, and T. Kovala, 1988,Biochemistry27, 6093–6098.